APPENDIX - Data Set Information Files
Project No: 165
Name: Naval Petroleum Reserve No. 4
Date Flown: 07/1945-08/1945 & 07/1946-08/1946
Altitude: 1000 feet Above Ground
Spacing: 2-4 miles, NE-SW
Merge Priority: 45
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Payne, T.G., and others, 1952, Aeromagnetic map of Naval Petroleum
Reserve No. 4 (Alaska), in Geology of the Arctic slope of Alaska: U.S.
Geological Survey Map OM-126, 3 sheets, scale 1:1,000,000.
2) Keller, Fred, Jr., and Henderson, J.R., 1954, Aeromagnetic survey of
Naval Petroleum Reserve No. 4 and adjacent areas, 1947: U.S. Geological
Survey Report RR10, 15 p.
3) Woolson, J.R., and others, 1962, Seismic and gravity surveys of Naval
Petroleum Reserve No. 4 and adjoining areas, Alaska: U.S. Geological
Survey Professional Paper 304-A, 125 p., aeromagnetic map scale
1:1,000,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 45/07/01 date and FLTSURF channel for elevation.
3) Processing Notes:
-247 nT datum shift applied
Tilt removed: 149.56,-0.000203548,0.0000419138
Decorrugation: None
Original "Info" file (edited):
Project no.: 165
Name: Naval Pet. Reserve No. 4
Flown by: U.S. Navy
Approximate number of line miles: 12,600
Instrument: An/ASQ-3A fluxgate magnetometer
Digitized by: Esther Castellanos, June, 1995
Map scale: 1:500,000
Datum: DGRF corrected (see USGS Open-file 95-835 for details)
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Total Field (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
Residual grid of Tien Grauch converted to XYZ points
NPRA data prepared for open-file release by Tien Grauch.
Released as:
Grauch, V.J.S., and Castellanos, Esther, 1995, Revised digital aeromagnetic
data for areas in and adjacent to the National Petroleum Reserve area
(NPRA), North Slope, Alaska: U.S. Geological Survey Open-File Rept.
95-835, 11 p.
"anonymous" ftp://greenwood.cr.usgs.gov/pub/open-file-reports/ofr-95-0835/
Digitized from map printed on linen (USGS Geophysics Files)
Map labeled as follows:
Aeromagnetic Map of Part of Naval Petroleum Reserve No. 4 and Adjacent
Areas, Alaska
Prepared in cooperation with the office of Naval Petroleum and
Oil Shale Reserves
Alaska General Report No. 10, Plate 1
magnetic base relative to arbitrary datum
scale 1:500,000
contour interval 10 gammas
1947
Area inside heavy boundary (center of map) flown 1945, compiled in
1945-46. Area outside heavy boundary (borders) flown in 1946, compiled
in 1946-47.
Maximum and minimum intensity values given on map.
This aeromagnetic map was prepared in 1946 and 1947 as a reconnaissance
aid to geological and geophysical exploration for petroleum in northern Alaska.
It was originally released in restricted reports to the U.S. Navy,
which has now approved publication in the present form.
Field data were measured with an An/ASQ-3A magnetometer installed in a PBY-5A
airplane flown 1,000 feet above the ground using a radar altimeter
for elevation measurement. Operation of the aircraft was by the
U.S. Navy. Traverses were made two to four miles apart as shown on the map.
U.S. Army Trimetrogon photographs were used for pilot guidance, and
final plotting was done on 1:500,000 scale World Aeronautical Charts.
A ground magnetometer station was maintained at Point Barrow to detect
magnetic storms, which occasionally prevented aeromagnetic surveying.
The magnetic anomalies appearing on the map are attributed mainly to
susceptibility changes in the crystalline basement rocks rather than to
basement topography. A good correlation exists between the magnetic map and
subsequent gravity surveys.
Note (from note attached to map)
Aeromagnetic data are obtained and compiled along a continuous line,
whereas ground mangetic surveys are made at separate points. Errors within
the normal limits of any magnetic measurement may cause slight
discrepancies between flight lines in an aeromagnetic map,
which would be more obvious than similar discrepancies between
points in a ground magnetic map.
For this reason as much care should be exercised in evaluating
magnetic features that appear as elongations along a single
aeromagnetic traverse as in interpreting an anomaly indicated
by a single ground station.
All flights at 1,000 feet above ground.
(map text entered by Rick Saltus, 22 June 1995)
***********************************************************
Project No: 0173 & 0193
Name: Copper River
Date Flown: 06/1954 & 06/1955
Altitude: 1200 feet Barometric
Spacing: 2 miles, N-S, and 1 mile, N-S
Merge Priority:
References:
1) G.E. Andreasen, and others, 1958; Aeromagnetic map of the
Copper River Basin, Alaska, USGS Geophysical Investigations
Map GP-156, scale 1:125,000.
Notes:
1) This is an integrated data set consisting of 2 original parts:
Survey 0173 in 1954 and Survey 193 in 1955. It has been redigitized along
contours as one survey.
3) As it is a barometric survey, the grid was draped to 1000' mean terrain
surface.
4) IGRF removed in original grid.
5) We have provided two distinct data bases in this case, one with the
originally digitized data 173_193.gdb, and one with data extracted from a
regular grid:
As data delivered to us were digitized along contours, the corresponding
profile data base 173_193.gdb is not of much practical use. We have
produced a new data base 173_193g.gdb, by gridding the digitized data
at 250 m grid cell size, tranposing the resulting grid in order to sample
in the actual flight line direction, and then extracting that grid to a new
database, with all relevant channels. MAG_COMP and MAG_MERGE were both
extracted from their corresponding grids.
Original "Info" file (edited):
Project no.: 173 & 193
Name: Copper River '54 and Copper River '55
Flown by: USGS
Number of line miles: 5550
Instrument: An/ASQ-3A fluxgate magnetometer
Digitized by: Esther Castellanos, August 1993
Publication: USGS Map GP-156
Map scale: 1:125,000
Datum: arbitrary datum
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Total Field (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
Background: These data digitized under supervision of Rick Saltus, USGS,
for inclusion in grid compilation for Interior Alaska
(for published USGS Map GP-1014). Work done in cooperation
with John Meyer, State of Alaska, Division of Oil and Gas.
***********************************************************
Project No: 174
Name: Fairbanks
Date Flown: 07/1954
Altitude: 2000 feet Barometric
Spacing: 1 mile, N-S
Merge Priority:
References:
1) Andreasen, G.E., Wahrhaftig, Clyde, and Zietz, Isidore, 1964, Aeromagnetic
reconnaissance of the east-central Tanana Lowland, Alaska: USGS Geophysical
Investigations Map GP-447, scale 1:125,000.
Notes:
1) Residual Total Field digitized from 1:125,000 scale contour maps-GP447
2) This survey was flown at 2000' barometric height. The residual channel
mag_raw in this case was draped to the 1000' height of the merged grid
(MAG_DRAPE channel)
3) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid:
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the merged grid.
*By subtracting from the profile data, the first order trend of the difference
between profile data and data extracted from the composite grid.
Where composite data were missing on the whole length of the profiles, a first
order trend of the profile data was removed in the final composite channel.
Original "Info" file:
Project no: 174
Name: Fairbanks
Flown by: USGS
Number of line miles: 1065
Instrument: An/ASQ-3A fluxgate magnetometer
Digitized from the 1:125,000-scale map.
Publication: USGS Map GP-447
Map scale: 1:125,000
Datum: arbitrary datum
***********************************************************
Project No: 177
Name: Nushagak Basin
Date Flown: 06/1954
Altitude: 1500 feet Barometric
Spacing: 2 miles, E-W
Merge Priority: 7
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Henderson, John R., and others, 1963, Aeromagnetic map of part of
the Dillingham Quadrangle, Alaska: USGS Geophysical Investigations
Map GP-352, 1:125,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 54/07/01 date, and FLTSURF channel for elevation.
3) Processing Notes:
-3502 nT datum shift applied
Decorrugation: None
Tilt Removed: 1141.82837,0.0002568769,-0.002122303
Original "Info" file (edited):
Project no.: 177
Name: Nushagak Basin
Flown by: USGS
Number of line miles: 1130
Instrument: An/ASQ-3A fluxgate magnetometer
Digitized by: DIGIMAP (Esther Castellanos, January 1997)
Publication: USGS Map GP-352
Map scale: 1:125,000
Datum: arbitrary datum
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Total Field (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
***********************************************************
Project No: 204A & 204B
Name: Ugashik North and South
Date Flown: 05/1955
Altitude: 1000-1300 feet Barometric
Spacing: 2 miles, N-S and NW-SE
Merge Priority: 55
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Andreasen, G.E., and others, 1963, Aeromagnetic map of part of the
Naknek quadrangle, Alaska: U.S. Geological Survey Geophysical
Investigations Map GP-353, scale 1:125,000.
2) G.E., Andreasen, and others, 1963, Aeromagnetic map of parts of the
Ugashik and Karluk quadrangles, Alaska: U.S. Geological Survey
Geophysical Investigations Map GP-354, scale 1:125,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 55/05/01 date.
3) Merged data from 204A & 204B, processed as one survey; constant barometric
altitude of 1150 ft. used for DGRF calculation.
4) Processing Notes:
-3193 nT datum shift applied
Decorrugation: None
Original "Info" file (edited):
Project no.: 204A and 204B
Name: Ugashik North and South
Flown by: USGS
Number of line miles: 2200
Instrument: An/ASQ-3A fluxgate magnetometer
Digitized by: Esther Castellanos, 1992
Publication: USGS GP-353 and GP-354
Map scale: 1:125,000
Datum: Arbitrary
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Total Field (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
***********************************************************
Project No: 550
Name: Alaska Regional (Aeromagnetic Map of Northeastern Alaska)
Date Flown: 07/1965-08/1965 (also includes data from 1954 and 1958)
Altitude: mostly 5000 ft barometric (higher in some mountainous
regions).
Spacing: Approximately 10.0 mi., N-S
Merge Priority: 95
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Brosge, W.P., Brabb, E.E., and King, E.R., 1970, Geologic
interpretation of reconnaissance aeromagnetic survey of north-eastern
Alaska: U.S. Geological Survey Bulletin 1271-F, 14 p., scale 1:1,000,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 55/05/01 date, and FLTSURF channel for elevation.
3) All values < 100 meters in the HEIGHT channel were set to 100 meters.
4) Processing Notes:
-237 nT datum shift applied
Decorrugation: None
Original "Info" file (edited):
Project no.: 550
Name: Alaska Regional
Flown by: USGS
Number of line miles: 9000
Instrument: continuous recording flux-gate magnetometer (analog)
Digitized by: DIGIMAP (Esther Castellanos, December 1996)
Map scale: 1:1,000,000
Datum: arbitrary datum, no diurnal corrections, regional field removed
("The gradient removed was represented by linear contours trend-
ing N 25 W so spaced that the gradient decreased from about
4 gammas per mile at the southwest corner of the map to about
3 gammas per mile at the northeast corner."
USGS Bulletin 1271-F, p. F5)
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Total Field (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
***********************************************************
Project No.: 3000
Name: Rat Island
Date Flown: 12/1966-01/1967
Altitude: 1600 feet Barometric
Spacing: 0.5 and 1 mile, NNE-SSW and WSW-ENE
Merge Priority:
References:
1) Bath, G.D., and others, 1972, Interpretation of an aeromagnetic survey of
the Amchitka Island area, Alaska: U.S. Geological Survey Professional
Paper 707, 25 p., scale 1:100,000.
Notes:
1) This data set was digitized along the original flight path at PGW from
USGS maps
2) Since it is an Aleutian island far S-W off shore from the mainland, it has
never been included in the compilation grids. That's why there are no
MAG_COMP and MAG_MERGE channels, and the USE_FLAG has all been set to 0.
Original "Info" file (edited):
Project no.: 3000
Name: Amchitka Island
Flown by: Aero Service Corp.
Number of line miles: 2300
Instrument: unknown
Digitized by: Paterson, Grant, and Watson
Publication: USGS Prof. Paper 707
Map scale: 1:100,000
***********************************************************
Project No: 3005H
Name: Hogatza Trend
Date Flown: 08/1968-10/1968
Altitude: 400 feet Above Ground
Spacing: 1 mile, E-W
Merge Priority: 23
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Miller, T.P., and Anderson, L.A., 1969, Airborne radioactivity and total
intensity magnetic survey of the southern Kobuk-Selawik Lowland,
western Alaska: U.S. Geological Survey Open-File Report 69-170, 6 p., 10
sheets, scale 1:63,360.
(Report includes 4 profiles to the northwest of area shown).
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 68/09/15 date, and FLTSURF channel for elevation.
3) Processing Notes:
-1755 nT datum shift applied
Decorrugation: None
Original "Info" file (edited):
Project no.: 3005H
Name: Hogatza Trend
Flown by: LKB
Number of line miles: 1450
Instrument: Gulf Mark III fluxgate magnetometer
Digitized by: DIGIMAP (Esther Castellanos) 1997
Publication: USGS OF 69-170
Map scale: 1:63,360 (20, 100, 500 nT contour intervals)
Datum: Arbitrary (No regional gradient removed)
Estimated total intensity of field 55,500 nT
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Total Field (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
***********************************************************
Project No: 3005J
Name: Southern Alaska Range (Lime Hills)
Date Flown: 08/1968-10/1968
Altitude: 7000, 7500 & 10000 feet barometric
Spacing: 1 mile, E-W
Merge Priority:
References:
1) Reed, B.L., and Anderson, L.A., 1969, Aeromagnetic maps of part of the
southern Alaska Range, U.S. Geological Survey Open-File Report 69-215,
6 p., scale 1:63,360.
Notes:
1) These are data digitized along actual flight path. There are three parts
flown at different barometric elevations: 7000', 7500' and 10000'.
2) Quality very poor.
3) Digitized data were first gridded (400m grid cell size) and the resulting
grids were draped at 1000' AG (Merged grid).
4) MAG_RAW would be the digitized data at actual barometric flight height.
MAG_DRAPE would be extracted from the corresponding draped grids at 1000'
AG, with a grid cell size of 400m.
5) Decorrugation applied to resulting grid.
6) Composite and merged grid directly extracted to the profile data base.
Original "Info" file (edited):
Project no: 3005J
Name: Southern Alaska Range
Flown by: LKB
Number of line miles: 1980
Instrument: Gulf Mark III fluxgate magnetometer
Digitized from the original 1:63,360-scale map
Publication: USGS OF 69-215
Map scale: 1:63,360
Datum: Arbitrary
***********************************************************
Project No: 3019
Name: North East Alaska '72 (Tanana & Livengood)
Date Flown: 07/1972-08/1972
Altitude: 1000 feet Above Ground
Spacing: 1.2 mile, N-S
Merge Priority:
References:
1) U.S. Geological Survey, 1973, Aeromagnetic survey, eastern part of
the Bettles Quadrangle, northeast Alaska, U.S. Geological Survey Open-File
Report 73-305, scale 1:250,000.
2) U.S. Geological Survey, 1973, Aeromagnetic survey, eastern part of
Wiseman Quadrangle, northeast Alaska, U.S. Geological Survey Open-File
Report 73-306, scale 1:250,000.
3) U.S. Geological Survey, 1973, Aeromagnetic survey, Melozitna A-1
Quadrangle, northeast Alaska, U.S. Geological Survey Open-File Report
73-307, scale 1:63,360.
4) U.S. Geological Survey, 1973, Aeromagnetic survey, Tanana Quadrangle,
northeast Alaska, U.S. Geological Survey Open-File Report 73-308,
scale 1:250,000.
5) U.S. Geological Survey, 1973, Aeromagnetic survey, western half of Beaver
Quadrangle, northeast Alaska, U.S. Geological Survey Open-File Report
73-309, scale 1:250,000.
6) U.S. Geological Survey, 1973, Aeromagnetic survey, western half of
Chandalar Quadrangle, northeast Alaska, U.S. Geological Survey Open-File
Report 73-310, scale 1:250,000.
7) U.S. Geological Survey, 1973, Aeromagnetic survey, western half of
Livengood Quadrangle, northeast Alaska, U.S. Geological Survey Open-File
Report 73-311, scale 1:250,000.
Notes:
1) IGRF removed in original data set.
2) Microlevelling was applied with the following parameters:
* Amplitude limit 20 nT
* Naudy filter lengh 4000 m.
Channel MAG_IGRF
3) Residual data were missing totally or partly on some of the lines, while raw
data were present and coherent. In these parts we do not have values for the
mag_merge and mag_comp channels, except for lines 1590, 1941 and ties 2560,
2550 where we levelled the raw data to the composite and merged grids.
4) The flight surface was calculated as DEM+ 305 m which was the nominal
flight height, since the radar altimeter data were not available in this
data set. Fltsurf=fltsurf_m because the survey height is the same as the
merged grid one.
5) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid :
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the corresponding grid.
Where composite data were missing on the whole length of the profiles, a first
order trend of the profile data was removed in the final composite channel.
Original "Info" file (edited):
Project no: 3019
Name: Northeast Alaska '72
Flown by: Aero Service
Number of line miles: 17,300
Instrument: Gulf Mark III fluxgate magnetometer
Notes: by Rick Saltus, USGS, Denver, 29 July 1993
The file f3019.ascii contains all the data with positions converted to
latitude and longitude. Inverse projection of the UTM coordinates was done
with Mike Webring's xyzprjrec program using standard USGS projection routines.
File f3019.ascii has the following format:
flightline (a4)
space (a1)
longitude (deg) f10.5
latitude (deg) f10.5
observed mag (nT) f8.1
adjusted mag (nT) f8.1
The adjusted mag field includes both IGRF (1965 updated to 1972.66) and
tie-line corrections made by Aero Service.
***********************************************************
Project No: 3020
Name: SE Alaska (Granite Fiords)
Date Flown: 08/1972-09/1972
Altitude: 6000 feet Barometric
Spacing: 1 mile, NE-SW
Merge Priority: 28
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1976, Aeromagnetic maps of Granite Fiords
Wilderness Study Area, Ketchikan and Bradfield Canal quadrangles,
southeastern Alaska: U.S. Geological Survey Open-File Report No.
76-558, 15 sheets, scale 1:63,360.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 72/08/15 date, and FLTSURF channel for elevation.
3) IGRF used 1965 model year, updated to 72/08/15, and 1828.8m (6000') for
elevation.
4) All values < 100 meters in the HEIGHT channel were set to 100 meters.
5) Processing Notes:
-307 nT datum shift applied
Decorrugation: None
Original "Info" file (edited):
Project no.: 3020
Name: Southeast Alaska (Granite Fiords)
Flown by: Aero Service
Number of line miles: 1700
Instrument: Gulf Mark III fluxgate magnetometer
Digitized by: Esther Castellanos, 8/1996
Publication: USGS OF 76-558
Map scale: 1:63,360
Datum: IGRF65
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Total Field (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
***********************************************************
Project No: 3029
Name: North East Alaska '73
Date Flown: 08/1973-09/1973
Altitude: 1000 feet Above Ground
Spacing: 1 mile, N-S
Merge Priority:
References:
1) U.S. Geological Survey, 1974, Aeromagnetic map of the Circle Quadrangle,
northeastern Alaska, U.S. Geological Survey Open-File Report 74-1101, scale
1:250,000.
2) U.S. Geological Survey, 1974,Aeromagnetic map of eastern half of the Beaver
Quadrangle, northeastern Alaska, U.S. Geological Survey Open-File Report
74-1102, scale 1:250,000.
3) U.S. Geological Survey, 1974, Aeromagnetic map of the eastern half of the
Chandalar Quadrangle, northeastern Alaska, U.S. Geological Survey Open-File
Report 74-1103, scale 1:250,000.
4) U.S. Geological Survey, 1974, Aeromagnetic map of eastern half of the
Livengood Quadrangle, northeastern Alaska, U.S. Geological Survey
Open-File Report 74-1104, scale 1:250,000.
Notes:
1) IGRF removed in original data set.
2) Microlevelling was applied with the following parameters:
* Amplitude limit 40 nT
* Naudy filter lengh 4000 m.
Channel MAG_IGRF
3) The flight surface was calculated as DEM+ 305 m which was the nominal flight
height, since the radar altimeter data were not available in this data set.
Fltsurf=fltsurf_m because the survey height is the same as the merged grid.
4) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid:
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the merged grid.
Since the merge grid exhibited flight line noise, we had to first remove that
noise by microlevelling the merge data extracted from the merged grid, and then
level our microlevelled data to the merged grid.
Where composite data were missing on the whole length of the profiles, a first
order trend of the profile data was removed in the final composite channel.
*By subtracting from the profile data, the first order trend of the difference
between profile data and data extracted from the composite grid.
Where composite data were missing on the whole length of the profiles, a first
order trend of the profile data was removed in the final composite channel.
Original "Info" file (edited):
Project no: 3029
Name: North East Alaska '73
Flown by: GeoMetrics
Number of lines miles: 15,562
Instrument: GeoMetrics G803 proton magnetometer
Datum: IGRF65, 56954 nT
Format: USGS 4, 94 wide
General: This format data is 94 characters/record. There is an 94 wide header
record which was added by NGDC to conform to other USGS standards.
Contents:
Columns Format Description
Header Record
1 - 25 A25 Project Name
26 - 41 A16 State and/or Country Project was flown in.
42 - 55 A14 Contractor
56 - 69 A14 Funding Agency
70 - 80 A11 NGDC Project Number(04 represents AEROMAGNETICS)
81 - 94 A4 Padding to end of record
Flight Line Record
none
Data Records
1 - 6 A6 Line number, within block
7 - 12 A6 Date of flight
13 - 24 F12.2 UTM easting(x), meters (False Easting 500,000 meters)
25 - 36 F12.2 UTM northing(y), meters (False Northing 3,000,000 meters)
37 - 48 F12.2 Sample number, corresponds to camera fiducial number
times ONC hom\nored, ie a sample number of 5800 = fiducial number 58.
49 - 60 F12.2 Total Field Magnetics in nT.
61 - 72 F12.2 Residual Magnetics in nT.
73 - 82 F12.6 Latitude in decimal degrees
83 - 94 F12.6 Longitude in decimal degrees
***********************************************************
Project No: 3030
Name: Southeast Alaska 1973
Date Flown: 08/1993-09/1973
Altitude: 6000 feet Barometric
Spacing: 1 mile, N63E
Merge Priority: 29
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey and U.S. Bureau of Mines,1984, Mineral resources
of the Tracy Arm-Fords Terror Wilderness Study Area and vicinity, Alaska
with a section on Interpretation of aeromagnetic data by R.C. Jachens:
U.S. Geological Survey Bulletin 1525, 308 p., scale 1:125,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 73/08/15 date, and FLTSURF channel for elevation.
3) IGRF used 1965 model year, updated to 73/08/15, and 1828.8m (6000') for
elevation.
4) All values < 100 meters in the HEIGHT channel were set to 100 meters.
5) Processing Notes:
-91 nT datum shift applied
Decorrugation: None
Original "Info" file (edited):
Project no.: 3030
Name: Southeast Alaska '73
Flown by: GeoMetrics
Instrument: GeoMetrics G-803 proton magnetometer
Digitized by: Esther Castellanos, 6/1996
Publication: unpublished 1:63,360 maps
Map scale: 1:63,360
Datum: data have IGRF 1965 updated to 1973 applied,
(This was evidently applied as a planar surface within each
15'x20' 1:63,360 quad)
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Total Field (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
***********************************************************
Project No: 3053
Name: McCarthy
Date Flown: 09/1974-02/1975
Altitude: 1000 feet Above Ground
Spacing: 1 mile, N-S
Merge Priority: 8
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1976, Aeromagnetic map of the McCarthy
1:250,000 (1¡ x 3¡) quadrangle, Alaska: U.S. Geological Survey
Open-File Report 76-170, scale 1:250,000.
2) Case, J.E., and MacKevett, E.M., Jr., 1976, Aeromagnetic map and
geologic interpretation of aeromagnetic map, McCarthy quadrangle, Alaska:
U.S. Geological Survey Miscellaneous Field Investigations Map MF-773-D,
2 sheets, scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 75/02/01 date, and FLTSURF channel for elevation.
3) All values < 100 meters in the HEIGHT channel were set to 100 meters.
4) Processing Notes:
-50 nT datum shift applied
Decorrugation:
BTWR 0.000155
DCOS-Dir 82
DCOS-Deg 0.5
Original "Info" file (edited):
Project no: 3053
Name: McCarthy
Flown by: Exploration Technology
Number of line miles: 7300
Instrument: Varian 4937A proton magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS3053TG04-0260-925 F R 840000USGS - Contractor: Exploration Technology01
USA Excalibur Beechcraft 3PLANE USGS Branch of Geophysics 02
McCarthy, Alaska ~7300 Traverse Miles 03
740900 750200 04
N-S: 1.0 Miles VARIAN 4937A 05
1000 Ft AG 01 IGRF-65 43738 < 2.0 nT06
FLIGHT-LINE-NUM(I6),DIR-FLOWN(I5),FID-NUM(F8.0),TIME(I7),X-MAP-POS(F10.3),
07
Y-MAP-POS(F10.3),TOTL-MAG-FIELD-INT-nT(F7.0),TOTL-CORR-MAG-FIELD-INT-
nT(F7.0),08
LONG-DEG(F11.6),LAT-DEG(F11.6),LAST-CARD(I2)| 09
10
11
1 7614,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +63+60-145-14116
W07363 17
Publication(s): Open-File Rept. 76-170 18
19
***********************************************************
Project No: 3054
Name: Talkeetna
Date Flown: 01/1975-02/1975
Altitude: 1000 feet Above Ground
Spacing: 1 mile, N-S
Merge Priority:
References:
1) Griscom, Andrew, 1979, Aeromagnetic and geologic interpretation
maps of the Talkeetna Quadrangle, Alaska, MF-870-B, scale 1:250,000.
Notes:
1) No "Flight elevation" data; no MAG_BASE data
2) IGRF removed in original data set.
3) Due to extreme high frequency noise in the profile data, a 3 fiducial's non
linear filter was applied to the data prior to levelling them to the
composite and merged grid.
4) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid :
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the merged grid.
*By subtracting from the profile data, the first order trend of the difference
between profile data and data extracted from the composite grid.
Where composite data were missing on the whole length of the profiles, a first
order trend of the profile data was removed in the final composite channel.
Original "Info" file (edited):
Project no: 3054
Name: Talkeetna
Flown by: Exploration Technology
Number of line miles: 800
Instrument: Varian 4937A proton magnetometer
This project was flown as a "fill-in" for State of Alaska project AK11.
National Geophysical Data Center (NGDC) data header:
cruise frmt NGDC Num fxdro_date contributing institution
4USGS3054ARO880260-907 F R 19840000USGS-Contractor:Exploration Technology 01
country platform pl.typ chief scientist(s)
USA Excalibur Beechcraft 3PLANE USGS Branch of Geophysics 02
project, cruise and leg
Talkeetna, Alaska ~800 Traverse Miles 03
date departure airport date arrival airport
19750100 19750200 04
flight line spacings magnetometer(s) used
N-S: 1.0 Miles Varian 4937A 05
aircraft altitude aircraft vel. samp tow-dist ref.field tot-obs mag sensitivi
1000 Ft AG 01 IGRF-65 18264 < 2.0 nT06
data parameter format (in Fortran) and units description
BLNK(1X),FLIGHT-LINE-NUM(I5),BLNK(1X),FID-NUM(I7),X-MAP-POSITION(F10.3),
07
Y-MAP-POSITION(F10.3),TOTL-COR-MAG-FIELD-nT(I7),TOTL-CALC-MAG-FIELD-
nT(I7), 08
LONG-DEG(F11.6),LAT-DEG(F11.6),LAST-CARD(I2)| 09
10
11
no. 10 degree area identifiers
1 7615,9999, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,12
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 13
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 14
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 15
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, +64+62-153-15116
tape locations
W00342 17
additional documentation
Publication(s): MF-870-B 18
This project was flown as a "fill-in" for State of Alaska project AK11. 19
***********************************************************
Project no: 3055
Name: Ruby
Date Flown: 01/1975-03/1975
Altitude: 1000 feet Above Ground
Spacing: 1 mile, N-S
Merge Priority:
References:
1) U.S. Geological Survey, 1976, Aeromagnetic map of the west one-half
of the Ruby 1:250,000 (1¡ x 3¡) Quadrangle, Alaska, OF Rept. 76-188,
scale 1:250,000.
Notes:
1) No "Flight elevation" data. No MAG_BASE data.
2) IGRF removed in original data set.
3) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid:
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the merged grid.
*By subtracting from the profile data, the first order trend of the difference
between profile data and data extracted from the composite grid.
Where composite data were missing on the whole length of the profiles, a first
order trend of the profile data was removed in the final composite channel.
Original "Info" file (edited):
Project no: 3055
Name: Ruby
Flown by: Exploration Technology
Number of line miles: 3300
Instrument: Varian 4937A proton magnetometer
National Geophysical Data Center (NGDC) data header:
cruise frmt NGDC Num fxdro_date contributing institution
4USGS3055ARO880260-928 F R 19840000USGS-Contractor:Exploration Technology 01
country platform pl.typ chief scientist(s)
USA Excalibur Beechcraft 3PLANE USGS Branch of Geophysics 02
project, cruise and leg
Ruby, Alaska ~3300 Traverse Miles 03
date departure airport date arrival airport
19750100 19750300 04
flight line spacings magnetometer(s) used
N-S: 1.0 Mile Varian 4937A 05
aircraft altitude aircraft vel. samp tow-dist ref.field tot-obs mag sensitivi
1000 Ft AG 01 IGRF-65 16172 < 2.0 nT06
data parameter format (in Fortran) and units description
FLIGHT-LINE-NUM(I6)
DIR-FLOWN(I5)
FID-NUM(F8.0)
TIME(I7)
X-MAP-POS(F10.3),
Y-MAP-POS(F10.3)
TOTL-MAG-FIELD-INT-nT(F7.0)
TOTL-CORR-MAG-FIELD-INT-nT(F7.0)
LONG-DEG(F11.6)
LAT-DEG(F11.6)
LAST-CARD(I2)|
no. 10 degree area identifiers
1 7615,9999, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,12
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 13
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 14
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 15
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, +66+63-157-15416
tape locations
W07363 17
additional documentation
Publication(s): Open-File Rept. 76-188 18
19
***********************************************************
Project No: 3069a
Name: Prince William Sound
Date Flown: 06/1975-09/1977
Altitude: 1000 feet Above Ground
Spacing: 1 mile, N-S
Merge Priority: 3
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1979, Aeromagnetic map of parts of the Cordova and
Middleton Island 1¡ x 3¡ quadrangles, Alaska: U.S. Geological Survey
Open-File Report 79-223, scale 1:250,000.
2) J.E., Case, and others, 1978, Geologic interpretation of aeromagnetic
map of the Seward and Blying Sound quadrangles, Alaska: U.S. Geological
Survey Miscellaneous Field Investigations Map MF-880-D, scale 1:250,000.
3) U.S. Geological Survey, 1978, Aeromagnetic map of Seward quadrangle,
Alaska: U.S. Geological Survey Open-File Report 78-1080, scale 1:250,000.
4) U.S. Geological Survey, 1978, Aeromagnetic map of Seward quadrangle,
Alaska, U.S. Geological Survey Open-File Report 78-1081, 32 sheets,
scale 1:63,360.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 76/06/30 date, and a constant of 304.8 (1000') for elevation.
3) Processing Notes:
+17 nT datum shift applied
Decorrugation:
BTWR 0.000155
DCOS-Dir 86.44
DCOS-Deg 0.5
Original "Info" file (edited):
Project No: 3069A
Name: Prince William Sound
Flown by: GeoMetrics
Number of line miles: 17,100
Instrument: GeoMetrics G-803 proton magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS3069TG04-0260-911 F R 840000USGS - Contractor: GeoMetrics, Inc. 01
USA Piper PA31 Navajo 3PLANE USGS Branch of Geophysics 02
Prince William Sound, Alaska ~17785 Traverse Miles 03
750600 770900 04
N-S: 1.0 Mile GeoMetrics G-803 05
1000 Ft AG 01 IGRF-75 534684 1.0 nT06
FLIGHT-LINE-NUM(A6),MONTH(A4),YR(A2),UTM-NORTH-M(F12.2),UTM-EAST-
M(F12.2), 07
FID-NUM(F12.2),TOTL-MAG-INT-nT(F12.2),RE-MAG-INT-nT(F12.2),DEG-LAT(F10.2), 08
DEG-LONG(F12.2)| 09
10
11
6 7513,7514,7515,7613,7614,7615,9999, , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +62+58-151-13816
W00342, 00330 17
Publication(s): Open-File Rept. 78-1080, 78-1081, 79-223, & F-880-D (#3069A) 18
79-224 (profiles) (#3069B) 19
20
***********************************************************
Project No: 3092
Name: Ketchikan
Date Flown: 05/1976-07/1976
Altitude: 6000 feet Barometric
Spacing: 1 mile, NE-SW
Merge Priority: 27
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1979, Aeromagnetic maps of parts of Ketchikan,
Prince Rupert, and Craig quadrangles, southeastern Alaska: U.S. Geological
Survey Open-File Report 79-937, 19 sheets, scale 1:63,360.
Notes:
1) Base station is NOT available for this survey.
2) IGRF used 1965 model year, updated to 76/06/01, and 1828.8m (6000') for
elevation.
3) DGRF used 76/06/01 date, and FLTSURF channel for elevation.
4) Processing Notes:
-352 nT datum shift applied
Decorrugation:
BTWR 0.000155
DCOS-Dir 280
DCOS-Deg 0.5
Original "Info" file (edited):
Project no.: 3092
Name: Ketchikan
Flown by: LKB Resources, Inc.
Number of line miles: 5300
Instrument: Modified ASQ-10 fluxgate magnetometer
Digitized by: Esther Castellanos, DIGIMAP, 3/1997
Publication: USGS OF 79-937
Map scale: 1:63,360
Datum: Arbitrary datum, regional field removed (IGRF 1965 updated to 1976)
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Total Field (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
***********************************************************
Project No: 3093b
Name: Glacier Bay-(middle section)
Date Flown: 01/1975-08/1976
Altitude: 15000 feet Barometric
Spacing: 1 mile, N35E
Merge Priority: 57
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Brew, D.A., and others, 1978, Mineral resources of the Glacier Bay
National Wilderness Study Area, Alaska: U.S. Geological Survey Open-
File Report 78-494, scale 1:125,000.
Notes:
1) Base station is NOT available for this survey.
2) Split 3093 into 3 surveys (m,n,s) due to different elevations.
3) DGRF used 75/07/17 date, and FLTSURF channel for elevation.
4) Barometric elevations were NOT available for this survey. Only 582
out of 18,613 HEIGHT (radar alt.) were present. Interpolation and
assumptions were used to fill in. Assumed missing HEIGHT > 5,200 ft. &
FLTSURF <2,200 meters. This processing was not applied in original
ACG and AMG compilation.
5) Processing Notes:
+1270 nT datum shift applied
Decorrugation: Middle
BTWR 0.000155
DCOS-Dir 110
DCOS-Deg 0.5
Original "Info" file (edited):
Project no: 3093B
Name: Glacier Bay West
Flown by: LKB Resources
Number of line miles: 1220
Instrument: Modified ASQ-10 fluxgate magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS3093TG04-0260-930 F R 850000USGS: Contractor - LK & B Resources Inc. 01
USA Cessna 310 Twin Eng. 3PLANE USGS Branch of Geophysics 02
Glacier Bay, Alaska ~5,447 Traverse Miles 03
750109 760719 04
NE - SW & NW - SE: 1.0 Miles Modified ASQ 10 Fluxgate 05
8 - 15,000 BARO 1STINGERIGRF65 Upd.77 189076 0.1 nT06
FLIGHT-LINE-NUMBER(I4),LINE-AZIMUTH(I4),FIDUCIAL-
NUMBER(I5),YEAR(I3),JULIAN- 07
DATE(I4),TIME-OF-SAMPLE(I7),UTM-EASTING-METERS(I8),UTM-NORTHING-
METERS(I8), 08
RADAR-ALTITUDE-FEET(I8),BAROMETRIC-ALTITUDE-FEET(I8),GROUND-STATION-
TOTAL-MAG-09
FIELD-nT(F11.2),OBSERVED-TOTAL-MAG-FIELD-nT(F11.2),ADJUSTED-TOTAL-MAG-
FIELD- 10
nT(F11.2),LATITUDE(F12.6),LONGITUDE(F12.6)| 11
2 7513,7613,9999, , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +61+58-139-13516
W07346 17
Publications: Open File Report OF78-494 18
Central Meridian = 135 W, False UTM Easting = 500 KM, False UTM Northing = 0. 19
The above mentioned UTM projection parameters were used to process LAT/LON 20
coordinates using the Clark 1866 spheroid. These projection figures are 21
ASSUMPTIONS used after every effort was made to obtain specifics relating to 22
the projection and coordinate system. PLEASE NOTE: The original UTM 23
coordinates are still present in the *.inp data set. 24
***********************************************************
Project No: 3093a
Name: Glacier Bay-(north section)
Date Flown: 01/1975-08/1976
Altitude: 8000 feet Barometric
Spacing: 1.0 mile, N35E
Merge Priority: 31
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Brew, D.A., and others, 1978, Mineral resources of the Glacier Bay
National Wilderness Study Area, Alaska: U.S. Geological Survey Open-
File Report 78-494, scale 1:125,000.
Notes:
1) Base station is NOT available for this survey.
2) Split 3093 into 3 surveys (m,n,s) due to different elevations.
3) DGRF used 75/06/12 date, and FLTSURF channel for elevation.
4) Barometric elevations were NOT available for this survey. Only 16,294
out of 54,526 HEIGHT (radar alt.) were present. Interpolation and
assumptions were used to fill in. Assumed missing HEIGHT > 5,200 ft.
except for lines in southeast. Southeast lines were HEIGHT ~= 1,000ft.
5) Processing Notes:
+1210 nT datum shift applied
Decorrugation: North
BTWR 0.000155
DCOS-Dir 110
DCOS-Deg 0.5
Original "Info" file (edited):
Project no: 3093A
Name: Glacier Bay East
Flown by: LKB Resources
Number of line miles: 3850
Instrument: Modified ASQ-10 fluxgate magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS3093TG04-0260-930 F R 850000USGS: Contractor - LK & B Resources Inc. 01
USA Cessna 310 Twin Eng. 3PLANE USGS Branch of Geophysics 02
Glacier Bay, Alaska ~5,447 Traverse Miles 03
750109 760719 04
NE - SW & NW - SE: 1.0 Miles Modified ASQ 10 Fluxgate 05
8 - 15,000 BARO 1STINGERIGRF65 Upd.77 189076 0.1 nT06
FLIGHT-LINE-NUMBER(I4),LINE-AZIMUTH(I4),FIDUCIAL-
NUMBER(I5),YEAR(I3),JULIAN- 07
DATE(I4),TIME-OF-SAMPLE(I7),UTM-EASTING-METERS(I8),UTM-NORTHING-
METERS(I8), 08
RADAR-ALTITUDE-FEET(I8),BAROMETRIC-ALTITUDE-FEET(I8),GROUND-STATION-
TOTAL-MAG-09
FIELD-nT(F11.2),OBSERVED-TOTAL-MAG-FIELD-nT(F11.2),ADJUSTED-TOTAL-MAG-
FIELD- 10
nT(F11.2),LATITUDE(F12.6),LONGITUDE(F12.6)| 11
2 7513,7613,9999, , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +61+58-139-13516
W07346 17
Publications: Open File Report OF78-494 18
Central Meridian = 135 W, False UTM Easting = 500 KM, False UTM Northing = 0. 19
The above mentioned UTM projection parameters were used to process LAT/LON 20
coordinates using the Clark 1866 spheroid. These projection figures are 21
ASSUMPTIONS used after every effort was made to obtain specifics relating to 22
the projection and coordinate system. PLEASE NOTE: The original UTM 23
coordinates are still present in the *.inp data set. 24
***********************************************************
Project No: 3093c
Name: Glacier Bay-(south section)
Date Flown: 01/1975-08/1996
Altitude: 5000 feet Barometric
Spacing: 1.0 mile, N35W
Merge Priority: 56
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Brew, D.A., and others, 1978, Mineral resources of the Glacier Bay
National Wilderness Study Area, Alaska: U.S. Geological Survey Open-
File Report 78-494, scale 1:125,000.
Notes:
1) Base station is NOT available for this survey.
2) Split 3093 into 3 surveys (m,n,s) due to different elevations.
3) DGRF used 76/06/21 date, and FLTSURF channel for elevation.
4) Removed Tie Lines T661, T662, T663, & T664
5) Barometric elevations were NOT available for this survey. 5,137
out of 6,258 HEIGHT (radar alt.) were present. Interpolation and
assumptions were used to fill in.
6) Processing Notes:
+1205 nT datum shift applied
Decorrugation: South
BTWR 0.000155
DCOS-Dir 40
DCOS-Deg 0.5
Original "Info" file (edited):
Project no: 3093C
Name: Glacier Bay West Coast
Flown by:LKB Resources
Number of line miles: 375
Instrument: Modified ASQ-10 fluxgate magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS3093TG04-0260-930 F R 850000USGS: Contractor - LK & B Resources Inc. 01
USA Cessna 310 Twin Eng. 3PLANE USGS Branch of Geophysics 02
Glacier Bay, Alaska ~5,447 Traverse Miles 03
750109 760719 04
NE - SW & NW - SE: 1.0 Miles Modified ASQ 10 Fluxgate 05
8 - 15,000 BARO 1STINGERIGRF65 Upd.77 189076 0.1 nT06
FLIGHT-LINE-NUMBER(I4),LINE-AZIMUTH(I4),FIDUCIAL-
NUMBER(I5),YEAR(I3),JULIAN- 07
DATE(I4),TIME-OF-SAMPLE(I7),UTM-EASTING-METERS(I8),UTM-NORTHING-
METERS(I8), 08
RADAR-ALTITUDE-FEET(I8),BAROMETRIC-ALTITUDE-FEET(I8),GROUND-STATION-
TOTAL-MAG-09
FIELD-nT(F11.2),OBSERVED-TOTAL-MAG-FIELD-nT(F11.2),ADJUSTED-TOTAL-MAG-
FIELD- 10
nT(F11.2),LATITUDE(F12.6),LONGITUDE(F12.6)| 11
2 7513,7613,9999, , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +61+58-139-13516
W07346 17
Publications: Open File Report OF78-494 18
Central Meridian = 135 W, False UTM Easting = 500 KM, False UTM Northing = 0. 19
The above mentioned UTM projection parameters were used to process LAT/LON 20
coordinates using the Clark 1866 spheroid. These projection figures are 21
ASSUMPTIONS used after every effort was made to obtain specifics relating to 22
the projection and coordinate system. PLEASE NOTE: The original UTM 23
coordinates are still present in the *.inp data set. 24
***********************************************************
Project No: 3102
Name: Phillip Smith Mountains
Date Flown: 10/1976-11/1976
Altitude: 1000 feet Above Ground
Spacing: 1.0 mile, N-S
Merge Priority: 32
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1977, Aeromagnetic map of the Philip Smith
Mountains quadrangle, Alaska: U.S. Geological Survey Open-File
Report 77-572, scale 1:250,000.
2) Cady, J.W., 1978, Aeromagnetic map and interpretation of the Philip
Smith Mountains quadrangle, Alaska: U.S. Geological Survey
Miscellaneous Field Investigations Map MF-879-E, scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 76/10/15 date, and HEIGHT channel for elevation.
3) Processing Notes:
+10 nT datum shift applied
Decorrugation:
BTWR 0.0001
DCOS-Dir 88
DCOS-Deg 1.0
Original "Info" file (edited):
Project no: 3102
Name: Phillip Smith Mountains
Flown by: GeoMetrics
Number of line miles: 5755
Instrument: GeoMetrics G-803 proton magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS3102TG04-0260-903 F R 840000USGS - Contractor: GeoMetrics, Inc. 01
USA Grumman Tracker S2F 3PLANE USGS Branch of Geophysics 02
Phillip Smith Mountains, Alaska ~5755 Traverse Miles 03
761000 761100 04
N-S: 1.0 Mile GeoMetrics G-803 05
1000 Ft AG 01 IGRF-65 203397 < 2.0 nT06
FLIGHT-LINE-NUM(A6),MONTH(A4),YR(A2),UTM-NORTH-M(F12.2),UTM-EAST-
M(F12.2), 07
FID-NUM(F12.2),TOTL-MAG-INT-nT(F12.2),RES-MAG-INT-nT(F12.2),DEG-LAT(F10.2),
08
DEG-LONG(F12.2)| 09
10
11
2 7614,7615,9999, , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +70+67-153-14616
W00314 17
Publications(s): Open-File Rept. 77-572 18
19
***********************************************************
Project No: 3103
Name: Chignik/Sutwik Island
Date Flown: 05/1977-07/1977
Altitude: 1000 feet Above Ground
Spacing: 1.0 mile, NW-SE
Merge Priority: 20
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1978, Aeromagnetic map of Chignik and Sutwik
Island quadrangles, Alaska: U.S. Geological Survey Open-File Report 78-262,
scale 1:250,000.
2) U.S. Geological Survey, 1978, Aeromagnetic maps of Chignik and Sutwik
Island quadrangles, Alaska: U.S. Geological Survey Open-File Report 78-263,
11 sheets, scale 1:63,360.
3) J.E., Case, and others, 1981, Maps showing aeromagnetic survey and
geologic interpretation of the Chignik and Sutwik Island quadrangles,
Alaska: U.S. Geological Survey Miscellaneous Field Invetigations Map
MF-1053-B, 2 sheets, scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 77/06/12 date, and a constant of 304.8m (1000') for elevation.
3) All "dropouts" (zero values) in the original HEIGHT channel were
changed to dummys for processing.
4) All "dropouts" (<= 51,000 nT) in the original MAG_RAW channel were
changed to dummys for processing.
5) Processing Notes:
-2178 nT datum shift applied
Decorrugation:
BTWR 0.000155
DCOS-Dir 52
DCOS-Deg 0.5
Original "Info" file (edited):
Project no: 3103
Name: Chignik/Sutwik
Flown by: LKB Resources
Number of line miles: 7380
Instrument: Modified ASQ-10 fluxgate magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS3103TG04-0260-920 F R 850000USGS: Contractor - LK & B Resources 01
USA Cessna 310 Twin Eng. 3PLANE USGS Branch of Geophysics 02
Chignik/Sutwik Island, Alaska ~18,314 Traverse Miles 03
770509 770724 04
NW - SE: 1.0 Miles Modified ASQ 10 Fluxgate 05
1000 FT AG 1STINGERIGRF65 Upd.77 337205 0.1 nT06
FLIGHT-LINE-NUMBER(I4),LINE-AZIMUTH(I4),FIDUCIAL-
NUMBER(I5),YEAR(I3),JULIAN- 07
DATE(I4),TIME-OF-SAMPLE(I7),UTM-EASTING-METERS(I8),UTM-NORTHING-
METERS(I8), 08
RADAR-ALTIMETER-FEET(I8),BAROMETRIC-ALTITUDE-FEET(I8),GROUND-STATION-
TOTAL- 09
MAGNETIC-FIELD-nT(F11.2),OBSERVED-TOTAL-MAG-FIELD-nT(F11.2),ADJUSTED-
TOTAL- 10
MAG-FIELD-nT(F11.2),LATITUDE(F12.6),LONGITUDE(F12.6)| 11
2 7515,7516,9999, , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +58+55-161-15616
W07348 17
Publications: Open File Report 78-262, 78-263 and MF-1053B 18
Central Meridian = 159 W, UTM False Easting = 500 KM, UTM False Northing = 0. 19
The above mentioned UTM projection parameters were used to process LAT/LON 20
coordinates using the Clark 1866 spheroid. These projection figures are 21
ASSUMPTIONS used after every effort was made to obtain specifics relating to 22
the projection and coordinate system. PLEASE NOTE: The original UTM 23
coordinates are still present in the *.inp data set. 24
***********************************************************
Project No: 3106
Name: Lake Clark
Date Flown: 7/1977-8/1978
Altitude: 1000 feet Above Ground
Spacing: 1.0 mile, NW-SE
Merge Priority: 2
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1978, Aeromagnetic map of the Lake Clark
1¡ x 3¡ quadrangle, Alaska: U.S. Geological Survey Open-File
Report 78-1086, scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 78/02/13 date, and a constant of 304.8m (1000') for elevation.
3) Processing Notes:
+35 nT datum shift applied
Decorrugation:
BTWR 0.000155
DCOS-Dir 47
DCOS-Deg 0.5
4) Original data file missing 33% of records. Reconstructed using NGA archive.
5) Line 472 was not in the NGA archive file, it was reconstructed from the
original 3106.dat file from USGS. Thus, it is discontinuous, missing 33
records out of every 100. It is included as one line, and these gaps
should be taken into account if it is to be used in further processing.
Original "Info" file(s) (edited):
Project no: 3106
Name: Lake Clark
Flown by: Aero Service
Number of line miles: 7555
Instrument: unknown
National Geophysical Data Center (NGDC) data header:
1USGS3106TG04-0260-910 F 840000USGS - Contractor: Aero Service, Inc. 01
USA Piper Navajo 3PLANE USGS Branch of Geophysics 02
Lake Clark, Alaska ~7555 Traverse Miles 03
770700Homer, Alaska, USA 780823Homer, Alaska, USA 04
NW-SE: 1.0 Mile 05
1000 Ft AG 01 IGRF-65 190321 < 2.0 nT06
FLIGHT-LINE-NUMBER(I8),FIDUCIAL-NUMBER(I8),UTM-EASTING-METERS(F10.0),
07
UTM-NORTHING-METERS(F10.0),RECORDED-TOTAL-FIELD-nT(I10),ADJUSTED-
TOTAL-FIELD- 08
nT(I10),RADAR-ALTITUDE-METERS(F10.1),BAROMETRIC-ALTITUDE-
METERS(I7),BLANK(5X),09
LATITUDE(F12.6),LONGITUDE(F12.6)| 10
11
2 7515,7615,9999, , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +62+59-157-15216
W00307 17
Publication(s): Open-File Rept. 78-1086 18
19
20
21
22
23
24
NGA NOTES:
File 3106.dat as received by NGA from the USGS was missing 33 of every 100
records, possibly due to a bad blocking-factor used when writing the tape.
Several of the fields present in the original file are absent from NGA's
archives. Line 472 is absent from NGA's archives; therefore, the available
records for Line 472 were recovered from 3106.dat.
Several errors were made in the original header file. Magnetics values must be
divided by 50 to recover total-field values. The fields in new3106.dat are:
FLIGHT-LINE-NUMBER(I8)
FIDUCIAL-NUMBER(I8)
UTM-EASTING-METERS(F10.0) available for Line 472 only
UTM-NORTHING-METERS(F10.0) available for Line 472 only
RECORDED-TOTAL-FIELD-nTx50(I10) available for Line 472 only, nTx50
ADJUSTED-TOTAL-FIELD-nTx50(I10) nTx50
RADAR-ALTITUDE-FEET(F10.1) to the nearest 10 feet, except Line 472
BAROMETRIC-ALTITUDE-FEET(I7)
BLANK(5X)
LATITUDE(F12.6)
LONGITUDE(F12.6)
***********************************************************
Project No: 3121
Name: Medfra
Date Flown: 06/1978-07/1978
Altitude: 1000 feet Above Ground
Spacing: 1 mile, N35W
Merge Priority:
References:
1) U.S. Geological Survey, 1979, Aeromagnetic map of the Medfra 1¡ x 3¡
Quadrangle, Alaska, U.S. Geological Survey Open-File Report 79-380,
scale 1:250,000.
Notes:
1) No MAG_BASE data
2) IGRF removed in original data set.
3) Decorrugation done prior to gridding
4) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid:
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the merged grid.
*By subtracting from the profile data, the first order trend of the difference
between profile data and data extracted from the composite grid.
Where composite data were missing on the whole length of the profiles, a first
order trend of the profile data was removed in the final composite channel.
Original "Info" file (edited):
Project no: 3121
Name: Medfra
Flown by: LKB Resources
Number of line miles: 6650
Instrument: Modified ASQ-10 fluxgate magnetometer
National Geophysical Data Center (NGDC) data header:
cruise frmt NGDC Num fxdro_date contributing institution
4USGS3121ARO880260-906 F R 19840000USGS-Contractor: LK&B Resources, Inc. 01
country platform pl.typ chief scientist(s)
USA Cessna 310B 3PLANE USGS Branch of Geophysics 02
project, cruise and leg
Medfra, Alaska ~6650 Traverse Miles 03
date departure airport date arrival airport
19780611McGrath, Alaska 19780709McGrath, Alaska 04
flight line spacings magnetometer(s) used
N35W: 1.0 Mile Modified ASQ-10 Fluxgate 05
aircraft altitude aircraft vel. samp tow-dist ref.field tot-obs mag sensitivi
1000 Ft AG 01STINGERIGRF-75 146561 < 1.0 nT06
data parameter format (in Fortran) and units description
FLIT-NUM(I4)
DIR-FLOWN(A2)
FID-NUM(I7)
YR&DAY(I5)
LAT-DEG(F8.4)
LONG-DEG(F9.4)07
ALT-M(I4)
BARO-ALT-M(I5)
TOTL-MAG-INT-nT(F8.2)
RES-TOTL-MAG-INT-nT(F8.2) 08
BLNK(4I5)| 09
10
no. 10 degree area identifiers 11
2 7614,7615,9999, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,12
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 13
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 14
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 15
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, +65+62-157-14516
tape locations
W00291 17
additional documentation
Publication(s): Open-File Rept. 79-380 18
***********************************************************
Project No: 3122
Name: Valdez
Date Flown: 07/1978-08/1978
Altitude: 1000 feet Above Ground
Spacing: 1 mile, N-S
Merge Priority:
References:
1) U.S. Geological Survey, 1979, Aeromagnetic map of part of the Valdez 1¡ x
3¡ Quadrangle, Alaska, U.S. Geological Survey Open-File Report 79-381,
scale 1:250,000.
Notes:
1) No MAG_BASE data
2) IGRF removed in original data set.
3) We have two flight line directions in this data set: one N_S and one
slightly NE-SW. Microlevelling was thus done separately for different flight
line directions, but with the same parameters:
Amplitude limit: 25 nT
Naudy filter length: 3000m
4) Line 151 was separated into 151 and 151.1, since those are two distinct
lines.
5) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid:
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the merge grid.
*By subtracting from the profile data, the first order trend of the difference
between profile data and data extracted from the composite grid.
Where composite data were missing on the whole length of the profiles, a first
order trend of the profile data was removed in the final composite channel.
Original "Info" file (edited):
Project No: 3122
Name: Valdez
Flown by: LKB Resources
Number of line miles: 6465
Instrument: Modified ASQ-10 fluxgate magnetometer
Files transferred from Natl Geophysical Data Center on 7/23/93.
File 0260-909.inp (3122)
10 data values (plus 4 zero columns) per line:
1. Line Number (I4)
2. Direction of line (A2)
3. Sample (fiducial) number (I7)
4. Year and Julian day of data collection (I5)
5. Latitude (F8.4)
6. Longitude (F9.4)
7. Height above terrain (radar altimeter) to nearest meter (I4)
8. Barometric altitude to nearest meter (I4)
9. Total field magnetic intensity to .01 gamma (nT) - datum corrected (F8.2)
10.Residual total magnetic field (IGRF removed). Datum of 56,000 nT added
(F8.2)
11.-14. Blank data fields (4I5)
First three lines of file:
VALDEZ ALASKA LKB RESOURCES 1978
201 N 3161078210 60.9795-146.9963 0 056833.2056825.23 0 0 0 0
201 N 3161178210 60.9801-146.9963 0 056832.3556824.21 0 0 0 0
***********************************************************
Project No: 3123
Name: Sitka (Yakobi & Chichagof Islands)
Date Flown: 08/1978
Altitude: 1000 feet Above Ground
Spacing: 0.5-1.0 mile, N60E (Azimuth 060)
Merge Priority: 16
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1979, Aeromagnetic map of Yakobi and Chichagof
Islands, Alaska: U.S. Geological Survey Open-File Report 79-529,
scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 78/08/22 date, and a constant of 304.8m (1000') for elevation.
3) All "dropouts" (defined as < 50000 nT) in the original MAG_RAW were
changed to dummys for processing.
4) Processing Notes:
-540 nT datum shift applied
Decorrugation:
None
Original "Info" file (edited):
Project No: 3123
Name: Sitka (Yakobi & Chichagof Islands)
Flown by: LKB Resources
Number of line miles: 3440
Instrument: Modified ASQ-10 fluxgate magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS3123TG04-0260-913 F R 840000USGS - Contractor: LKB Resources, Inc. 01
USA Cessna 310B 3PLANE USGS Branch of Geophysics 02
Sitka (Yakobi & Chichagof Islands), Alaska ~3440 Traverse Miles 03
780819Sitka, AK 780825Sitka, AK 04
N60E: 0.5-1.0 Mile Modified ASQ-10 Fluxgate 05
1000 Ft AG 01STINGERIGRF-75 62410 < 1.0 nT06
FLIT-NUM(I4),DIR-FLOWN(A2),FID-NUM(I7),YR&DAY(I5),LAT-DEG(F8.4),LONG-
DEG(F9.4)07
,ALT-M(I4),BARO-ALT-M(I5),TOTL-MAG-INT-nT(F8.2),RES-TOTL-MAG-INT-nT(F8.2),
08
BLNK(4I5) 09
10
11
3 7512,7513,9999, , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +59+57-137-13516
W00291 17
Open File Reports: OF79-529, OF79-1694 18
This survey was done along with the Medfra (3121) and Valdez (3122) quad- 19
rangles. The entire survey was done between 780606 and 780825 and consisted 20
of 52 flights and 16,555 linear miles. 21
22
***********************************************************
Project No: 3138
Name: Petersburg
Date Flown: 08/1978
Altitude: 1000 feet Above Ground
Spacing: 1.0 mile, N60E (Azimuth 060)
Merge Priority: 17
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1979, Aeromagnetic map of the Petersburg area,
Alaska: U.S. Geological Survey Open-File Report 79-832, scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 78/08/22 date, and a constant of 304.8m (1000') for elevation.
3) All "dropouts" (zero values) in the original HEIGHT channel were
changed to dummys for processing.
4) Processing Notes:
-720 nT datum shift applied
Decorrugation:
BTWR 0.000167
DCOS-Dir 315
DCOS-Deg 0.5
Original "Info" file (edited):
Project no: 3138
Name: Petersburg
Flown by: LKB Resources
Number of line miles: 8650
Instrument: Modified ASQ-10 fluxgate magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS3138TG04-0260-914 F R 840000USGS - Contractor: LKB Resources, Inc. 01
USA Cessna & Aerocmdr 3PLANE USGS Branch of Geophysics 02
Petersburg, Alaska ~8650 Traverse Miles 03
780803Petersburg, AK 780908Petersburg, AK 04
N60E: 1 Mile Modified ASQ 10 Fluxgate 05
1000 Ft AG 01STINGERIGRF-75 197772 < 1.0 nT06
FLIT-NUM(I4),DIR-FLOWN(A2),FID-NUM(I7),YR&DAY(I5),LAT-DEG(F8.4),LONG-
DEG(F9.4)07
,ALT-M(I4),BARO-ALT-M(I5),TOTL-MAG-INT-nT(F8.2),RES-TOTL-MAG-INT-nT(F8.2),
08
BLNK(4I5)| 09
10
11
1 7513,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +58+55-135-13016
W00327 17
Publication(s): Open-File Rept. 79-832 18
19
***********************************************************
Project No: 3177
Name: Chugach
Date Flown: 06/79-07/79
Altitude: 1000 feet Above Ground
Spacing: 1 mile, N50W
Merge Priority:
References:
1) U.S. Geological Survey, 1980, Aeromagnetic map of the Chugach area,
Alaska, U.S. Geological Survey Open-File Report 80-058, scale 1:250,000.
Notes:
1) This is a data set from the original grid. The actual profiles are roughly
E-W while the original flight line direction is N50W.
2) Quality very poor.
3) IGRF removed in original data set.
4) A great deal of line to line levelling noise present in the data, as well
as groups of lines poorly levelled with respect to the rest of the grid.
This was taken care of by applying two consecutive decorrugations respecting
the original flight line direction, and using two different central wave
numbers for the Butterworth filter, namely, one correponding to the flight
line spacing, and one approximately five times the flight line spacing.
Since the resulting maximum amplitudes of the noise grids did not exceed
20 nT, no further microlevelling was applied.
5) The resulting decorrugated grid was then extracted to the data base as
mag_dcor channel, which was subsequently used to obtain the mag_merge and
mag_comp channels.
6) Since the survey was was flown at 1000' above ground, fltsurf=fltsuf_m.
The height channel missing, fltsurf was calculated as dem+305m (here dem is
the channel extracted from the available digital elevation model grid).
7) In order to preserve the higher resolution of the digitized data, we have
levelled the final residual magnetic field to the composite or to the merged
grid:
*By subtracting from the profile data(in this case the mag_dcor channel), a
long wave lengh component (i.e. low pass filtered) of the difference between
profile data and data extracted from the merged grid.
*By subtracting from the profile data, the first order trend of the difference
between profile data and data extracted from the composite grid.
Where composite data were missing on the whole length of the profiles, a first
order trend of the profile data was removed in the final composite channel.
Original "Info" file (edited):
Project No: 3177
Name: Chugach
Flown by: LKB Resources
Number of line miles: 1705
Instrument: Modified ASQ-10 fluxgate magnetometer
After examining corresponding profiles columns 5 and 6 should be
interchanged. - Rick Saltus 9/29/93)
Gridded data from contractor. Row 1, Col 1 is in SW corner of area.
1. Row number (I5)
2. Column number (I5)
3. UTM Easting to the nearest meter (F10.0)
4. UTM Northing to the nearest meter (F10.0)
Guess on UTM coordinates: Central meridian = -147 degrees (?)
False easting = 500000 m (?)
Guess on meaning of two mag values:
5. Adjusted (IGRF removed, but 56,000 nT added back) magnetic intensity value,
in nT (F10.2)
6. Gridded magnetic intensity value before IGRF removal, in nT (F10.2)
First three lines of file:
ANCHORAGE ALASKA LKB RESOURCESUNIVAC1108
23 351 473700. 6759900. 56321.73 57385.32
23 352 474000. 6759900. 56318.66 57381.46
***********************************************************
Project No: 3178
Name: Afognak
Date Flown: 06-07/79
Altitude: 1000 feet Above Ground
Spacing: 1.0 mi. N50W
Merge Priority: 25
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1980, Aeromagnetic map of Afognak Island and
vicinity, Alaska: U.S. Geological Survey Open-File Report 80-057,
scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 79/06/15 date, and a constant of 304.8m (1000') for elevation.
3) All "dropouts" (zero values) in the original HEIGHT channel were
changed to dummys for processing.
4) Processing Notes:
+310 nT datum shift applied
Decorrugation:
BTWR 0.0001
DCOS-Dir 042
DCOS-Deg 1.0
Original "Info" file (edited):
Project No: 3178
Name: Afognak
Flown by: LKB Resources
Number of line miles: 1845
Instrument: Modified ASQ-10 fluxgate magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS3178TG04-0260-917 F R 840000USGS - Contractor: LKB Resources, Inc. 01
USA 3PLANE USGS Branch of Geophysics 02
Afognak, Alaska ~1845 Traverse Miles 03
790600 790700 04
N50W: 1.0 Mile Modified ASQ-10 Fluxgate 05
1000 Ft AG 01 IGRF-75 41331 0.1 nT06
FLIT-NUM(I4),DIR-FLOWN(A2),FID-NUM(I7),YR&DAY(I5),LAT-DEG(F8.4),LONG-
DEG(F9.4)07
,ALT-M(I4),BARO-ALT-M(I5),TOTL-MAG-INT-nT(F8.2),RES-TOTL-MAG-INT-nT(F8.2),
08
BLNK(4I5)| 09
10
11
2 7514,7515,9999, , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +59+57-154-14316
W00327 17
Publications(s): Open-File Rept. 80-057 18
19
***********************************************************
Project No: 4038
Name: Ugashik-Karluk
Date Flown: 10/1980
Altitude: 1000 feet Above Ground
Spacing: 1.0 mile, NW-SE
Merge Priority: 22
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1981, Aeromagnetic map of the Ugashik-Karluk
area, Alaska: U.S. Geological Survey Open-File Report 81-1158,
scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 80/10/01 date, and a constant of 304.8m (1000') for elevation.
3) All "dropouts" (zero values) in the original HEIGHT channel were
changed to dummys for processing.
4) All "dropouts" (<= 50,000 nT) in the original MAG_RAW channel were
changed to dummys for processing.
5) Processing Notes:
+92 nT datum shift applied
Decorrugation:
BTWR 0.000155
DCOS-Dir 050
DCOS-Deg 0.5
Original "Info" file (edited):
Project no: 4038
Name: Ugashik-Karluk
Flown by: Fugro GeoMetrics
Number of line miles: 3423
Instrument: GeoMetrics G-803 proton magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS4038TG04-0260-918 F R 840000USGS - Contractor: Fugro GeoMetrics, Inc.01
USA TE AeroCommander 680E3PLANE USGS Branch of Geophysics 02
Ugashik-Karluk, Alaska ~3423 Traverse Miles 03
801000King Salmon, AK 801000King Salmon, AK 04
NW-SE: 1.0 Mile GeoMetrics G-803 05
1000 Ft AG 01STINGERIGRF-75 80800 1.0 nT06
FLIT-NUM(I4),DIR-FLOWN(A2),FID-NUM(I7),YR&DAY(I5),LAT-DEG(F8.4),LONG-
DEG(F9.4)07
08
BLNK(4I5) 09
10
11
1 7515,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +59+56-159-15516
W00317 17
Publication(s): Open-File Rept. 81-1158 18
19
***********************************************************
Project No: 4092a (North)
Name: Killik River-Chandler Lake
Date Flown: 06/1982
Altitude: 4000 feet Barometric
Spacing: 2 miles, E-W
Merge Priority: 43
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1983, Aeromagnetic map of the Killik River and
Chandler Lake 1¡ by 3¡ quadrangles, Alaska: U.S. Geological Survey
Open-File Report 83-607, scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) "Flight elevation" listed below in original info is height above ground.
3) DGRF used 82/06/15 date, and due to some spikes in the barometric elevation
channel, a constant value of 1219.14 meters, (4000 feet).
4) Processing Notes:
-104 nT datum shift applied
Decorrugation:
BTWR 0.00003
DCOS-Dir 3
DCOS-Deg 1.0
Original "Info" files (edited):
Project no: 4092A
Name: Killik River-Chandler Lake North
Flown by: Diversified Technical Service
Number of line miles: 3360
Instrument: GeoMetrics G-803 H.P. proton magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS4092TG04-0260-902 F R 840000USGS - Contractor: Diversified Tech Serv 01
USA Hunting-Pembroke 3PLANE USGS Branch of Geophysics 02
Killik River-Chandler Lake, Alaska ~6720 Traverse Miles 03
820619 820625 04
E-W: 2.0 Miles GeoMetrics G-803 H.P. 05
N-4000;S-8000 Ft BAR 01 IGRF-75 133769 0.25 nT06
FLIT-NUM(I4),DIR-FLOWN(A2),FID-NUM(I7),YR&DAY(I5),LAT-DEG(F8.4),LONG-
DEG(F9.4)07
,ALT-M(I4),BARO-ALT-M(I5),TOTL-MAG-INT-nT(F8.2),RES-TOTL-MAG-INT-nT(F8.2),
08
BLNK(4I5)| 09
10
11
2 7614,7615,9999, , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +70+68-157-14916
W00321 17
Publication(s): Open-File Rept. 83-607 18
19
20
Data records are Longitude (degrees), Latitude (degrees), Mag (nT), Flight
elevation (meters).
Mag values are total field in nanoTeslas.
***********************************************************
Project No: 4092b (South)
Name: Killik River-Chandler Lake
Date Flown: 06/1982
Altitude: 8000 feet Barometric
Spacing: 2 miles, E-W
Merge Priority: 44
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1983, Aeromagnetic map of the Killik River and
Chandler Lake 1¡ by 3¡ quadrangles, Alaska: U.S. Geological Survey
Open-File Report 83-607, scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) "Flight elevation" listed below in original info is height above ground.
3) DGRF used 82/06/15 date, and due to some spikes in the barometric elevation
channel, a constant value of 2726.4 meters, (8000 feet).
4) Processing Notes:
-127 nT datum shift applied
Decorrugation:
BTWR 0.0000777
DCOS-Dir 1
DCOS-Deg 1.0
Original "Info" file (edited):
Project no: 4092B
Name: Killik River-Chandler Lake South
Flown by: Diversified Technical Services
Number of line miles: 3360
Instrument: GeoMetrics G-803 H.P. proton magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS4092TG04-0260-902 F R 840000USGS - Contractor: Diversified Tech Serv 01
USA Hunting-Pembroke 3PLANE USGS Branch of Geophysics 02
Killik River-Chandler Lake, Alaska ~6720 Traverse Miles 03
820619 820625 04
E-W: 2.0 Miles GeoMetrics G-803 H.P. 05
N-4000;S-8000 Ft BAR 01 IGRF-75 133769 0.25 nT06
FLIT-NUM(I4),DIR-FLOWN(A2),FID-NUM(I7),YR&DAY(I5),LAT-DEG(F8.4),LONG-
DEG(F9.4)07
,ALT-M(I4),BARO-ALT-M(I5),TOTL-MAG-INT-nT(F8.2),RES-TOTL-MAG-INT-nT(F8.2),
08
BLNK(4I5)| 09
10
11
2 7614,7615,9999, , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +70+68-157-14916
W00321 17
Publication(s): Open-File Rept. 83-607 18
19
20
21
Data records are Longitude (degrees), Latitude (degrees), Mag (nT), Flight
elevation (meters).
Mag values are total field in nanoTeslas.
***********************************************************
Project No: 4093
Name: Healy
Date Flown: 06/1982
Altitude: 1000 feet Above Ground
Spacing: 1 mile, N-S
Merge Priority:
References:
1) U.S. Geological Survey, 1984, Aeromagnetic map of the western part
of the Healy, 1¡ by 3¡ Quadrangle, Alaska, U.S. Geological Survey
Open-File Report 84-295, scale 1:250,000.
Notes:
1) The original data file is extracted from a grid, along E-W lines, while the
original flight line direction is N-S.
2) IGRF removed in original data set.
3) Decorrugation done prior to gridding.
4) Because of the very poor quality of the grid, and of extremely large
discrepancies with other surveys in overlapping areas, in this case the
mag_comp and mag_merge channels were merely extracted from the corre-
sponding grids.
Original "Info" file (edited):
Project no: 4093
Name: Healy
Flown by: Diversified Technical Services
Number of line miles: 2470
Instrument: GeoMetrics G-803 H.P. proton magnetometer
File healy.grd (4093):
Gridded data from contractor. Row 1, Col 1 is in SW corner of area.
1. Row number (I5)
2. Column number (I5)
3. UTM Easting to the nearest meter (F10.0)
4. UTM Northing to the nearest meter (F10.0)
Note on UTM coordinates: Central meridian = -141 degrees
False easting = 500000 m
5. Gridded magnetic intensity value before IGRF removal, in nT (F10.2)
6. Adjusted (IGRF removed) magnetic intensity value, in nT (F10.2)
First three lines of file:
HEALY, ALASKA ALASKA HIGH LIFE - QEB-147500000
1 1 349000. 6982000.-999999.99 -70.86
1 2 349500. 6982000.-999999.99 -62.87
The actual file healy.grd had all dummies in item # 5 (namely the gridded
magnetic intensity value before IGRF removal)
***********************************************************
Project No: 4094
Name: Anchorage
Date Flown: 07/1982
Altitude: 1000 feet Above Ground
Spacing: 1 mile, N30W
Merge Priority:
References:
1) U.S. Geological Survey, 1984, Aeromagnetic map of part of the
Anchorage 1¡ by 3¡ Quadrangle, Alaska, U.S. Geological Survey
Open-File Report 84-352, scale 1:250,000.
Notes:
1) IGRF removed in original data set.
2) Microlevelling was applied with the following parameters:
* Naudy filter length 5000 m.
No amplitude limiting applied. Channel MAG_IGRF
3) Radar altimeter data (height channel) are of very poor quality and were
clipped at a value of 673 m, certainly on around 60% of the area.
Fltsurf=fltsurf_m because the survey height is the same as the merged grid.
4) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid:
*By subtracting from the profile data, a long wave length component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the corresponding grid.
Where composite data were missing on the whole length of the profiles, a first
order trend of the profile data was removed in the final composite channel.
Original "Info" file (edited):
Project no. 4094
Name: Anchorage
Flown by: Diversified Technical Services
Number of line miles: 3970
Instrument: GeoMetrics G-803 H.P. proton magnetometer
National Geophysical Data Center (NGDC) data header:
cruise frmt NGDC Num fxdro_date contributing institution
4USGS4094ARO880260-908 F R 19840000USGS - Contractor: Diversified Tech Ser01
country platform pl.typ chief scientist(s)
USA Hunting-Pembroke 3PLANE USGS Branch of Geophysics 02
project, cruise and leg
Anchorage, Alaska ~3970 Traverse Miles 03
date departure airport date arrival airport
19830700Anchorage, AK 19830700Anchorage, AK 04
flight line spacings magnetometer(s) used
N30W: 1.0 Mile Geometrics G-803 H.P. 05
aircraft altitude aircraft vel. samp tow-dist ref.field tot-obs mag sensitivi
1000 Ft AG 01 IGRF-75 96876 0.25 nT06
data parameter format (in Fortran) and units description
FLIT-NUM(I4)
DIR-FLOWN(A2)
FID-NUM(I7)
YR&DAY(I5),LAT-DEG(F8.4)
LONG-DEG(F9.4)07
ALT-N(I4)
BARO-ALT-M(I5)
TOTL-MAG-INT-nT(F8.2)
RES-TOTL-MAG-INT-nT(F8.2),
BLNK(9I5)| 09
10
11
no. 10 degree area identifiers
2 7614,7615,9999, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,12
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 13
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 14
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 15
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, +62+60-151-14716
tape locations
W00321 17
additional documentation
Publication(s): Open-File Rept. 84-352 18
19
***********************************************************
Project No: 4095a
Name: Craig
Date Flown: 08/1982-09/1982
Altitude: 1000 feet Above Ground
Spacing: 1.0 mile, N-S
Merge Priority: 18
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1984, Aeromagnetic map of the Craig area,
Alaska: U.S. Geological Survey Open-File Report 84-666, 3 sheets,
scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 82/08/22 date, and a constant of 304.8m (1000') for elevation.
3) All "dropouts" (<= zero values) in the original HEIGHT channel were
changed to dummys for processing.
4) Processing Notes:
-132 nT datum shift applied
Decorrugation:
BTWR 0.000155
DCOS-Dir 79
DCOS-Deg 0.5
Original "Info" file (edited):
Project no. 4095A
Name: Craig
Flown by: Diversified Technical Services
Number of line miles: 5730
Instrument: GeoMetrics G-803 H.P. proton magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS4095TG04-0260-921 F R 840000USGS - Contractor: Diversified Tech Serv 01
USA Hunting-Pembroke 3PLANE USGS Branch of Geophysics 02
Craig, Alaska ~6710 Traverse Miles 03
820815 820903 04
N-S,E-W,N68E: 1 Mile GEOMETRICS G-803 H.P. 05
1000 Ft AG 01 IGRF-75 153555 0.25 nT06
FLIT-NUM(I4),DIR-FLOWN(A2),FID-NUM(I7),YR&DAY(I5),LAT-DEG(F8.4),LONG-
DEG(F9.4)07
,ALT-M(I4),BARO-ALT-M(I5),TOTL-MAG-INT-nT(F8.2),RES-TOTL-MAG-INT-nT(F8.2),
08
BLNK(4I5)| 09
10
11
1 7513,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +57+54-135-13116
W00317 17
Publication(s): Open-File Rept. 84-666 18
The USGS considers this project to be three seperate surveys. 19
20
21
***********************************************************
Project No: 4095b
Name: Northwest Craig
Date Flown: 08/1982-09/1982
Altitude: 1000 feet Above Ground
Spacing: 1.0 mile, E-W
Merge Priority: 19
"Merge Priorirty" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1984, Aeromagnetic map of the Craig area,
Alaska: U.S. Geological Survey Open-File Report 84-666, 3 sheets,
scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 82/08/22 date, and a constant of 304.8m (1000') for elevation.
3) All "dropouts" (<= zero values) in the original HEIGHT channel were
changed to dummys for processing.
4) Processing Notes:
-87 nT datum shift applied
Decorrugation:
BTWR 0.000155
DCOS-Dir 349
DCOS-Deg 0.5
Original "Info" file (edited):
Project no. 4095B
Name: Northwest Craig
Flown by: Diversified Technical Services
Number of line miles: 630
Instrument: GeoMetrics G-803 H.P. proton magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS4095TG04-0260-921 F R 840000USGS - Contractor: Diversified Tech Serv 01
USA Hunting-Pembroke 3PLANE USGS Branch of Geophysics 02
Craig, Alaska ~6710 Traverse Miles 03
820815 820903 04
N-S,E-W,N68E: 1 Mile GEOMETRICS G-803 H.P. 05
1000 Ft AG 01 IGRF-75 153555 0.25 nT06
FLIT-NUM(I4),DIR-FLOWN(A2),FID-NUM(I7),YR&DAY(I5),LAT-DEG(F8.4),LONG-
DEG(F9.4)07
,ALT-M(I4),BARO-ALT-M(I5),TOTL-MAG-INT-nT(F8.2),RES-TOTL-MAG-INT-nT(F8.2),
08
BLNK(4I5)| 09
10
11
1 7513,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +57+54-135-13116
W00317 17
Publication(s): Open-File Rept. 84-666 18
The USGS considers this project to be three seperate surveys. 19
20
21
***********************************************************
Project No: 4095c
Name: Southern Craig
Date Flown: 08/1982-09/1982
Altitude: 1000 feet Above Ground
Spacing: 1.0 mile, N68E
Merge Priority: 26
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1984, Aeromagnetic map of the Craig area,
Alaska: U.S. Geological Survey Open-File Report 84-666, 3 sheets,
scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 82/08/22 date, and a constant of 304.8m (1000') for elevation.
3) All "dropouts" (<= zero values) in the original HEIGHT channel were
changed to dummys for processing.
4) Processing Notes:
-93 nT datum shift applied
Decorrugation:
BTWR 0.000155
DCOS-Dir 325
DCOS-Deg 0.5
Original "Info" file (edited):
Project no. 4095C
Name: Southern Craig
Flown by: Diversified Technical Services
Number of line miles: 350
Instrument: GeoMetrics G-803 H.P. proton magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS4095TG04-0260-921 F R 840000USGS - Contractor: Diversified Tech Serv 01
USA Hunting-Pembroke 3PLANE USGS Branch of Geophysics 02
Craig, Alaska ~6710 Traverse Miles 03
820815 820903 04
N-S,E-W,N68E: 1 Mile GEOMETRICS G-803 H.P. 05
1000 Ft AG 01 IGRF-75 153555 0.25 nT06
FLIT-NUM(I4),DIR-FLOWN(A2),FID-NUM(I7),YR&DAY(I5),LAT-DEG(F8.4),LONG-
DEG(F9.4)07
,ALT-M(I4),BARO-ALT-M(I5),TOTL-MAG-INT-nT(F8.2),RES-TOTL-MAG-INT-nT(F8.2),
08
BLNK(4I5)| 09
10
11
1 7513,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +57+54-135-13116
W00317 17
Publication(s): Open-File Rept. 84-666 18
The USGS considers this project to be three seperate surveys. 19
20
***********************************************************
Project No: 4096a
Name: Ugashik Northwest
Date Flown: 07/1982
Altitude: 1000 feet Above Ground
Spacing: 1.0 mile, NW-SE
Merge Priority: 21
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1984, Aeromagnetic map of parts of the Ugashik
and Karluk 1¡ by 2¡ quadrangles, Alaska: U.S. Geological Survey
Open-File Report 84-351, 2 sheets, scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 82/07/15 date, and a constant of 304.8m (1000') for elevation.
3) Processing Notes:
-46 nT datum shift applied
Decorrugation: None
4) Tie lines 181, 182, & 183 were not use in the gridding.
Original "Info" file (edited):
Project no. 4096A
Name: Ugashik Northwest
Flown by: Diversified Technical Services
Number of line miles: 2475
Instrument: GeoMetrics G-803 H.P. proton magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS4096TG04-0260-919 F R 840000USGS - Contractor: Diversified Tech Serv 01
USA Hunting-Pembroke 3PLANE USGS Branch of Geophysics 02
Ugashik, Alaska ~3335 Traverse Miles 03
820709 820720 04
NW-SE: 1.0 Mile GeoMetrics G-803 H.P. 05
1000 Ft AG 01 IGRF-75 68574 0.25 nT06
FLIT-NUM(I4),DIR-FLOWN(A2),FID-NUM(I7),YR&DAY(I5),LAT-DEG(F8.4),LONG-
DEG(F9.4)07
,ALT-M(I4),BARO-ALT-M(I5),TOTL-MAG-INT-nT(F8.2),RES-TOTL-MAG-INT-nT(F8.2),
08
BLNK(4I5)| 09
10
11
1 7515,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +59+56-158-15416
W00321 17
Publication(s): Open-File Rept. 84-351 18
The USGS considers this project to be three separate surveys. 19
20
***********************************************************
Project No: 4096b
Name: Ugashik South
Date Flown: 07/1982
Altitude: 1000 feet Above Ground
Spacing: 1.0 mile, NW-SE
Merge Priority: 21
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1984, Aeromagnetic map of parts of the Ugashik
and Karluk 1¡ by 2¡ quadrangles, Alaska: U.S. Geological Survey
Open-File Report 84-351, 2 sheets, scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 82/07/15 date, and a constant of 304.8m (1000') for elevation.
3) Processing Notes:
-62 nT datum shift applied
Decorrugation: None
4) Tie lines 187, & 188 were not used in the gridding.
Original "Info" file (edited):
Project no. 4096B
Name: Ugashik South
Flown by: Diversified Technical Services
Number of line miles: 350
Instrument: GeoMetrics G-803 H.P. proton magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS4096TG04-0260-919 F R 840000USGS - Contractor: Diversified Tech Serv 01
USA Hunting-Pembroke 3PLANE USGS Branch of Geophysics 02
Ugashik, Alaska ~3335 Traverse Miles 03
820709 820720 04
NW-SE: 1.0 Mile GeoMetrics G-803 H.P. 05
1000 Ft AG 01 IGRF-75 68574 0.25 nT06
FLIT-NUM(I4),DIR-FLOWN(A2),FID-NUM(I7),YR&DAY(I5),LAT-DEG(F8.4),LONG-
DEG(F9.4)07
,ALT-M(I4),BARO-ALT-M(I5),TOTL-MAG-INT-nT(F8.2),RES-TOTL-MAG-INT-nT(F8.2),
08
BLNK(4I5)| 09
10
11
1 7515,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +59+56-158-15416
W00321 17
Publication(s): Open-File Rept. 84-351 18
The USGS considers this project to be three separate surveys. 19
20
***********************************************************
Project No: 4096c
Name: Ugashik Northeast
Date Flown: 07/1982
Altitude: 1000 feet Above Ground
Spacing: 1.0 mile, NW-SE
Merge Priority: 21
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1984, Aeromagnetic map of parts of the Ugashik
and Karluk 1¡ by 2¡ quadrangles, Alaska: U.S. Geological Survey
Open-File Report 84-351, 2 sheets, scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 82/07/15 date, and a constant of 304.8m (1000') for elevation.
3) Processing Notes:
-101 nT datum shift applied
Decorrugation: None
4) Tie lines 184, 185, & 186 were not used in the gridding.
Original "Info" file (edited):
Project no. 4096C
Name: Ugashik Northeast
Flown by: Diversified Technical Services
Number of line miles: 510
Instrument: GeoMetrics G-803 H.P. proton magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS4096TG04-0260-919 F R 840000USGS - Contractor: Diversified Tech Serv 01
USA Hunting-Pembroke 3PLANE USGS Branch of Geophysics 02
Ugashik, Alaska ~3335 Traverse Miles 03
820709 820720 04
NW-SE: 1.0 Mile GeoMetrics G-803 H.P. 05
1000 Ft AG 01 IGRF-75 68574 0.25 nT06
FLIT-NUM(I4),DIR-FLOWN(A2),FID-NUM(I7),YR&DAY(I5),LAT-DEG(F8.4),LONG-
DEG(F9.4)07
,ALT-M(I4),BARO-ALT-M(I5),TOTL-MAG-INT-nT(F8.2),RES-TOTL-MAG-INT-nT(F8.2),
08
BLNK(4I5)| 09
10
11
1 7515,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +59+56-158-15416
W00321 17
Publication(s): Open-File Rept. 84-351 18
The USGS considers this project to be three separate surveys. 19
20
***********************************************************
Project No: 4097
Name: Juneau
Date Flown: 07/1982-08/1982
Altitude: 7000 feet Barometric
Spacing: 1.0 mile, N50E
Merge Priority: 30
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1984, Aeromagnetic map of the Juneau area,
Alaska: U.S. Geological Survey Open-File Report 84-296, scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 82/08/09 date, and FLTSURF channel for elevation.
3) Original HEIGHT channel was clearly bad so we used FLTSURF
(BARO-ALT-M in original data) minus topo extracted from 300 meter
grid for HEIGHT.
3) Processing Notes:
+32 nT datum shift applied
Decorrugation:
BTWR 0.000155
DCOS-Dir 305
DCOS-Deg 0.5
Original "Info" file (edited):
Project no. 4097
Name: Juneau
Flown by: Diversified Technical Services
Number of line miles: 3360
Instrument: GeoMetrics G-803 H.P. proton magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS4097TG04-0260-912 F R 840000USGS - Contractor: Diversified Tech Serv 01
USA Hunting-Pembroke 3PLANE USGS Branch of Geophysics 02
Juneau, Alaska ~4100 Traverse Miles 03
820726 820814 04
N50E: 1.0 Mile GeoMetrics G-803 H.P. 05
7000 Ft BAR 01 IGRF-75 92067 0.25 nT06
FLIT-NUM(I4),DIR-FLOWN(A2),FID-NUM(I7),YR&DAY(I5),LAT-DEG(F8.4),LONG-
DEG(F9.4)07
,ALT-M(I4),BARO-ALT-M(I5),TOTL-MAG-INT-nT(F8.2),RES-TOTL-MAG-INT-nT(F8.2),
08
BLNK(4I5)| 09
10
11
1 7513,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +60+57-136-13316
W00321 17
Publication(s): Open-File Rept. 84-296 (4094), Healy (4093)-gridded, Killik 18
River/Chandler Lake (4092), Ugashik (4096), and Craig (4095). 19
20
NOTES:
Dummied out a spike in Line 60.1, fid 1371, in barometric alt., and height.
Dummied out spikes in Line 61, fids 4-6 in height.
Dummied out spikes in Line 62, fid 806 in baro, height; 1010,
1035, 1169-1171, 1182, 1253-1255 in height.
Dummied out spikes in Line 63, fid 432 in Height.
Dummied out spikes in height in:
Line 65, fids 233, 471
Line 66, fids 933, 981
Line 69, fid 171
Line 71, fids 61-64, 66-68
***********************************************************
Project No: 4123
Name: Wrangell Mountains
Date Flown: 08/1984
Altitude: 1000 feet Above Ground
Spacing: 1 mile, E-W
Merge Priority:
References:
1) U.S. Geological Survey, 1985, Aeromagnetic map of part of the Wrangell
Mountains, Alaska, U.S. Geological Survey Open-File Report 85-605,
scale 1:250,000.
Notes:
1) No MAG_BASE channel present in original data
2) Although in the original header file the radar altimeter channel is labeled
to be in meters, the data range indicates that it probably is in feet, so
that it has been accordingly rescaled by multiplying it by 0.3048.
3) IGRF removed in original data set.
4) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid :
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted
from the merge grid.
*By subtracting from the profile data, the first order trend of the difference
between profile data and data extracted from the composite grid.
Where composite data were missing on the whole (or most of the) length of the
profiles, a first order trend of the profile data was removed in the final
composite channel.
Original "Info" file (edited):
Project no. 4123
Name: Wrangell Mountains
Flown by: Airborne Geophysics
Number of line miles: 2500
Instrument: GeoMetrics G-813 magnetometer
National Geophysical Data Center (NGDC) data header:
cruise frmt NGDC Num fxdro_date contributing institution
4USGS4123ARO880260-923 F R 19840000USGS-Contractor:Airborne Systems, Inc. 01
country platform pl.typ chief scientist(s)
USA Piper Chieftain 3PLANE USGS Branch of Geophysics 02
project, cruise and leg
Wrangel Mountains, Alaska ~2500 Traverse Miles 03
date departure airport date arrival airport
19840805Gulkana, AK 19840813Gulkana, AK 04
flight line spacings magnetometer(s) used
E-W: 1.0 Mile GeoMetrics G-813 05
aircraft altitude aircraft vel. samp tow-dist ref.field tot-obs mag sensitivi
1000 Ft AG 01STINGERIGRF-80 67734 0.1 nT06
data parameter format (in Fortran) and units description
FLIT-NUM(I4)
DIR-FLOWN(A2)
FID-NUM(I7)
YR&DAY(I5)
LAT-DEG(F8.4)
LONG-DEG(F9.4)07
ALT-M(I4)
BARO-ALT-M(I5)
TOTL-MAG-INT-nT(F8.2)
RES-TOTL-MAG-INT-nT(F8.2)
BLNK(4I5)| 09
10
11
no. 10 degree area identifiers
1 7614,9999, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,12
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 13
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 14
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 15
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, +63+61-146-14216
tape locations
W04788 17
additional documentation Publication(s): Open-File Rept. 85-605 18
19
***********************************************************
Project No: 4150
Name: Middleton Island
Date Flown: 10/1987-11/1987
Altitude: 500 feet Above Ground
Spacing: 1.0 mile, N-S
Merge Priority: 9
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) U.S. Geological Survey, 1988, Aeromagnetic map of part of the Middleton
Island quadrangle, and vicinity, Alaska: U.S. Geological Survey Open-File
Report 88-505, scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 87/09/17 date, and FLTSURF channel for elevation.
3) Processing Notes:
-11 nT datum shift applied
Decorrugation:
BTWR 0.000167
DCOS-Dir 85
DCOS-Deg 0.5
Original "Info" file (edited):
Project no. 4150
Name: Middleton Island
Flown by: Aero Service
Number of line miles: 8000
Instrument: Cesium magnetometer
National Geophysical Data Center (NGDC) data header:
1USGS4150TG04-0260-927 F R 900000USGS - Contractor: Aero Services 01
USA Cessna 320?? 3PLANE USS Branch of Geophysics 02
Middleton Island, Alaska ~8000 Traverse Miles 03
871001 871119 04
N-S: 1.0 Mile Cesium Magnetometer 05
500 Ft AG 01yes IGRF-85 324480 0.01 nT06
FLIGHT-LINE-NUM(I4),DIR-FLOWN(A2),FID-
NUM(I7),YR(I2),JDATE(I3),HR(I2),MIN(I2),07
SEC(I2),LAT-DEG(F8.4),LONG-DEG(F9.4),ALT-M(I4),BAR-ALT-M(I5),TOTL-MAG-INT-
nT 08
(F8.2),RES-TOTL-MAG-INT-nT(F8.2)| 09
10
11
2 7514,7614,9999, , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +61+58-148-14316
W01244 17
Publication(s): Open-File Rept. 88-505 18
19
***********************************************************
Project No: 4160A, 4160B
Name: Annette Island
Date Flown: 07/1986-08/1986
Altitude: 60 meters Above Ground
Spacing: 200 meters, 400 meters, NE-SW
Merge Priority: 15
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Horton, R. J., Long, C. L., and Senterfit, R. M., 1988, Helicopter-borne
geophysical survey of the Annette Island Indian Reservation, Southeast
Alaska: U.S. Geological Survey Administrative Report, BIA-88-1.
2) Griscom, A., and Sauer, P. E., 1993, Annette Island aeromagnetic studies:
in Mineral assessment project, Annette Islands Reserve, project summary
and mineral resource assessment, U. S. Geological Survey Administrative
Report 93-84-II, p. 21-30.
3) Godwin, L.H., and Smith, B.D.,editors, 1993, Economic mineral resources
of the Annette Islands Reserve, Alaska: Northwest Mining Association,
136 p.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used FLTSURF and 86/08/03 date.
3) Processing Notes:
+140 nT datum shift applied
Decorrugation: None
* MAG_COMP = MAG_DGRF - 53.92; 53.92 is difference between mean of MAG_DGRF
and COMP_GRID.
* MAG_MERGE is the upward-continued MAG_DGRF data with the linear
trend of the difference between the "Merged" grid and upward-continued,
MAG_DGRF grid removed. That trend was:
C0=-115.40
Cx=0.0099408162
Cy=0.0036183278
* Line 2480 has major problems and does not appear to fit with adjacent lines.
Line 2480 was excluded from most of the processing but is included here for
completeness.
Original "Info" files (edited):
Project no. 4160A and 4160B
Name: Annette Island
Flown by: Aerdat
Number of line miles: 620
Instrument: unknown
Annette Island aeromagnetic survey data fields:
Flightline number
Longitude
Latitude
Total field anomaly = total field = IGRF
Total field
Height above terrain (meters)
Barometric altitude (meters)
Fiducial number
Year and dat (YYMMDD.0)
Fortran format:
(a8,f10.4,f9.4,f8.2,f9.2,3f8.2,f11.3)
***********************************************************
Project No: 5006
Name: Four Corners
Date Flown: 09/1979
Altitude: 400 feet Above Ground
Spacing: 1 mile, N-S
Merge Priority:
References:
1) Aero Service Corporation, 1980, Airborne gamma-ray spectrometer and
magnetometer survey; Four Corners detail area, portions of Kantishna
River, Mt.McKinley Medfra and Ruby quadrangles, by U.S. Department of
Energy, Grand Junction Office Report GJBX-116(80), scale 1:125,000.
Notes:
1) "Flight elevation" listed below in original info is height above ground.
2) IGRF removed in original data set.
3) Quality OK. No microlevelling required prior to merging.
4) Since the survey was flown at 400' nominal height, and the merged grid was
merged at 1000 feet, profile data for the MAG_MERGE channel were accordingly
upward continued before adjusting them to the merged grid.
5) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid :
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the merged grid.
*By subtracting from the profile data, the first order trend of the difference
between profile data and data extracted from the composite grid.
Where composite data were missing on the whole length of the profiles, a first
order trend of the profile data was removed in the final composite channel.
Original "Info" file (edited):
Project no.: 5006
Name: Four Corners
Flown by: Aero Service
Number of line miles: 688
Instrument: GeoMetrics G-803 proton magnetometer
NOTES 29 July 1993:
The original ascii data file mtmckinley.nure containing NURE mag data for the
5006 survey (Aero Services, 1979) was provided by Richard W. Saltus (USGS).
The original data file contained the following:
FORMAT: N.U.R.E. #1, (NATIONAL URANIUM RESOURCE EVALUATION)
Format for Magnetic Data Records
Columns Format Description
1 I1 Aerial System Identification Code
2 I4 Flight Line Number
3 I6 Record Identification Number
4 I6 GMT Time of Day (HHMMSS)
5 F8.4 Latitude to Four Decimal Places in Degrees
6 F8.4 Longitude to Four Decimal Places in Degrees
7 F6.1 Terrain Clearance to One Decimal Place in Meters
8 F5.1 Outside Air Pressure to One Decimal Place in MMHG
9 A8 Surface Geologic Map Unit Code
10 F7.1 Total Magnetic Field Intensity to One Decimal Place
in Gammas
11 F7.1 Residual (IGRF Removed) Magnetic Field Intensity to
One Decimal Place in Gammas
12 F7.1 Diurnal Magnetic Intensity Variation to One Decimal
Place in Gammas
13 F7.1 Magnetic Depth-To-Basement to One Decimal Place in
Meters (if Required) (not available)
***********************************************************
Project No: 6008
Name: Seward-Selawik
Date Flown: 06/1975-07/1975
Altitude: 400 feet Above Ground
Spacing: 6 miles, E-W
Merge Priority: 47
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Texas Instruments, Inc. 1975, Airborne geophysical survey , Copper River
and Seward-Selawik areas, Alaska: U.S. Energy Research and Development
Administration, Grand Junction Office Report GJO-1653, 2 vols., scales
1:250,000 and 1:500,000.
Notes:
1) Base station is NOT available for this survey.
2) "Flight elevation" listed below in original info is height above ground.
3) Line 56 was not used in preparation of grids and was removed from this data
set.
4) This is a very poor data set.
5) DGRF used FLTSURF and 75/07/01 date.
6) Processing Notes:
+76 nT datum shift applied
Decorrugation: None
Original "Info" file (edited):
Project no. 6008
Name: Seward-Selawik
Flown by: Texas Instruments
Number of line miles: 7630
Instrumentation: Geometrics G-803 magnetometer
NOTES 3 September 1996:
6008.XYZZ contains NURE mag data for the 6008 survey (Texas Instruments, 1975).
Data file "ti003r.1o" obtained from Fred Riggle, USGS, Reston. File
converted to ascii format. Only those records with non-zero mag value that
fell within the area of the 6008 survey were retained (about 80% of the
original data file).
Data records are Longitude (degrees), Latitude (degrees), Mag (nT), Flight
elevation (ft)
Mag values are total field in nanoTeslas.
***********************************************************
Project No: 6016 West
Name: Yukon
Date Flown: 05/1976-08/1976
Altitude: 400 feet Above Ground
Spacing: 6 miles, E-W
Merge Priority:
References:
1) Texas Instruments, Inc., 1977,Aerial gamma-ray and magnetic survey
of the Bethel and Yukon areas, Alaska: U.S. Energy Research and
Development Administration, Grand Junction Office Report GJBX-005(77),
16 vols.
Notes:
1) This is an integrated data set consisting in 2 original parts:
Melozitna and Kateel River. Data have been all imported into one gdb, namely
6016.gdb.
2) "Flight elevation" listed below in original info is height above ground.
3) Quality poor.
4) Data were filtered with a 3.5 km. low pass filter prior to gridding.
5) Since the survey was flown at 400' nominal height, and the merged grid was
merged at 1000 feet, profile data for the MAG_MERGE channel were accordingly
upward continued before adjusting them to the merged grid.
6) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid :
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the merged grid.
*By subtracting from the profile data, the first order trend of the difference
between profile data and data extracted from the composite grid.
Where composite data were missing on the whole length of the profiles, a first
order trend of the profile data was removed in the final composite channel.
The original Kateel River data file kateel.Nure was heavily desampled, so
that a new one had to be obtained in 1996 from the USGS: 0420-544.dat
Original "Info" file (edited):
Project no. 6016
Name: Yukon
Flown by: Texas Instruments
Number of line miles: 9700 (total for all quadrangles)
Instrument: GeoMetrics G-803 proton magnetometer
NOTES:
Melozitna 29 July 1993
Kateel River April 1996
The original ascii data file Melozitna.nure containing NURE mag data for this
6016 survey (Texas Instruments, 1977) was provided by Richard W. Saltus (USGS).
The original data file contained the following:
FORMAT: N.U.R.E. #1, (NATIONAL URANIUM RESOURCE EVALUATION)
Format for Magnetic Data Records
Columns Format Description
1 I1 Aerial System Identification Code
2 I4 Flight Line Number
3 I6 Record Identification Number
4 I6 GMT Time of Day (HHMMSS)
5 F8.4 Latitude to Four Decimal Places in Degrees
6 F8.4 Longitude to Four Decimal Places in Degrees
7 F6.1 Terrain Clearance to One Decimal Place in Meters
8 F5.1 Outside Air Pressure to One Decimal Place in MMHG
9 A8 Surface Geologic Map Unit Code
10 F7.1 Total Magnetic Field Intensity to One Decimal Place
in Gammas
11 F7.1 Residual (IGRF Removed) Magnetic Field Intensity to
One Decimal Place in Gammas
12 F7.1 Diurnal Magnetic Intensity Variation to One Decimal
Place in Gammas (not available for these data sets)
13 F7.1 Magnetic Depth-To-Basement to One Decimal Place in
Meters (if Required) (not available)
***********************************************************
Project No: 6016 East
Name: Yukon
Date Flown: 07/1976
Altitude: 400 feet Above Ground
Spacing: 6 miles, E-W
Merge Priority: 46
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Texas Instruments, Inc., 1977,Aerial gamma-ray and magnetic survey
of the Bethel and Yukon areas, Alaska: U.S. Energy Research and
Development Administration, Grand Junction Office Report GJBX-005(77),
16 vols.
Notes:
1) Three quadrangle areas, 6016a, 6016b, and 6016c, were combined and
processed as one survey (Coleen, Black River, and Ft. Yukon).
2) DGRF used FLTSURF and 76/07/12 date.
3) Processing Notes:
+25 nT datum shift applied
Decorrugation: None
Original "Info" files (edited):
Project no. 6016
Name: Yukon
Flown by: Texas Instruments
Number of line miles: 9700 (total for all quadrangles)
Instrument: GeoMetrics G-803 proton magnetometer
National Geophysical Data Center (NGDC) data headers:
1NUR6016ATG04-0420-616 F R 890000DOE - Flown by Texas Instruments 01
USA Douglas Super DC-3 3PLANE DOE - Bendix Field Engineering 02
Coleen, Alaska 03
760706 760712 04
E-W: 6 miles proton precession 05
400 ft. AG 150 mph 1.8100 ft.IGRF 14168? 06
AERIAL-SYS-ID-CODE(I1),FLIGHT-LINE-NUM(I4),RECORD-ID-NUM(I6),GMT-TIME-OF-
DAY- 07
HHMMSS(I6),LAT-DEG(F8.4),LONG-DEG(F8.4),TERRAINE-CLEAR-
METERS(F6.1),OUTSIDE 08
-AIR-PRESSURE-MMHG(F5.1),SURFACE-GEOLOGICAL-MAP-UNIT-CODE(A8),TOTAL-
MAG-FIELD-09
INTENSITY-nT(F7.1),RESIDUAL-MAG-FIELD-INTENSITY-nT(F7.1),DIURNAL-MAG-
INTENSITY10
-VARIATION-nT(F7.1),MAG-DEPTH-TO-BASEMENT-METERS(F7.1)| 11
1 7614,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +68+67-144-14116
W05157 17
Open file Report: GJBX-005(77) 18
Open file Contoured Map: GJM-045 19
Magnetic Data Tape: XS0591, file 15 20
Radiometric Data Tape: 464, file 3 TI 21
1NUR6016BTG04-0420-615 F R 890000DOE - Flown by Texas Instruments 01
USA Douglas Super DC-3 3PLANE DOE - Bendix Field Engineering 02
Black River, Alaska 03
760703 760719 04
E-W: 6 miles proton precession 05
400 ft. AG 150 mph 1.8100 ft.IGRF 14722? 06
AERIAL-SYS-ID-CODE(I1),FLIGHT-LINE-NUM(I4),RECORD-ID-NUM(I6),GMT-TIME-OF-
DAY- 07
HHMMSS(I6),LAT-DEG(F8.4),LONG-DEG(F8.4),TERRAINE-CLEAR-
METERS(F6.1),OUTSIDE 08
-AIR-PRESSURE-MMHG(F5.1),SURFACE-GEOLOGICAL-MAP-UNIT-CODE(A8),TOTAL-
MAG-FIELD-09
INTENSITY-nT(F7.1),RESIDUAL-MAG-FIELD-INTENSITY-nT(F7.1),DIURNAL-MAG-
INTENSITY10
-VARIATION-nT(F7.1),MAG-DEPTH-TO-BASEMENT-METERS(F7.1)| 11
1 7614,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +67+66-144-14116
W 17
Open file Report: GJBX-005(77) 18
Open file Contoured Map: GJM-041 19
Magnetic Data Tape: XS0664, file 3 20
Radiometric Data Tape: 464, file 4 TI 21
1NUR6016CTG04-0420-603 F R 890000DOE - Flown by Texas Instruments 01
USA Douglas Super DC-3 3PLANE DOE - Bendix Field Engineering 02
Fort Yukon, Alaska 03
760703 760721 04
E-W: 6 miles proton precession 05
400 ft. AG 150 mph 1.8100 ft.IGRF 14740? 06
AERIAL-SYS-ID-CODE(I1),FLIGHT-LINE-NUM(I4),RECORD-ID-NUM(I6),GMT-TIME-OF-
DAY- 07
HHMMSS(I6),LAT-DEG(F8.4),LONG-DEG(F8.4),TERRAINE-CLEAR-
METERS(F6.1),OUTSIDE 08
-AIR-PRESSURE-MMHG(F5.1),SURFACE-GEOLOGICAL-MAP-UNIT-CODE(A8),TOTAL-
MAG-FIELD-09
INTENSITY-nT(F7.1),RESIDUAL-MAG-FIELD-INTENSITY-nT(F7.1),DIURNAL-MAG-
INTENSITY10
-VARIATION-nT(F7.1),MAG-DEPTH-TO-BASEMENT-METERS(F7.1)| 11
1 7614,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +67+66-148-14416
W05237 17
Open file Report: GJBX-005(77) 18
Open file Contoured Map: GJM-040 19
Magnetic Data Tape: XS0588, file 13 20
Radiometric Data Tape: 464, file 2 TI 21
22
***********************************************************
Project No: 6017 and 6018
Name: Bethel and Nunivak Island
Date Flown: 05/1976-08/1976
Altitude: 400 AG
Spacing: 6 miles, E-W
Merge Priority: 34
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Texas Instruments, Inc., 1977,Aerial gamma-ray and magnetic survey
of the Bethel and Yukon areas, Alaska: U.S. Energy Research and
Development Administration, Grand Junction Office Report GJBX-005(77),
16 vols.
Notes:
1) Merged flight lines from 6017a-j & 6018, processed as one survey.
2) Base station is NOT available for this survey.
3) "Flight elevation" listed below in original info is height above ground.
4) HEIGHT was missing for lines L126.1, L127.1, L128.0, T600.1, and T601.1.
We inserted the nominal terrain separation of 122 meters (400 ft.) in those
lines.
5) These 5 line segments were not available for the first AKMAG compilation,
thus the MAG_COMP and MAG_MERGE channels have been changed to dummies.
6) DGRF used FLTSURF and 76/07/01 date.
7) Processing Notes:
+65 nT datum shift applied
Decorrugation: None
Original "Info" file(s) (edited):
Project no. 6017 and 6018
Name: Bethel and Nunivak Island
Flown by: Texas Instruments
Number of line miles: 7950 (both areas)
Instrument: GeoMetrics G-803 proton magnetometer
National Geophysical Data Center (NGDC) data header:
1NUR6017ATG04-0420-511 F R 890000DOE - Flown by Texas Instruments 01
USA Douglas Super DC-3 3PLANE DOE - Bendix Field Engineering 02
St. Michael, Alaska 03
760612 760614 04
E-W: 6 miles proton precession 05
400 ft. AG 150 mph 1.8100 ft.IGRF 3859? 06
AERIAL-SYS-ID-CODE(I1),FLIGHT-LINE-NUM(I4),RECORD-ID-NUM(I6),GMT-TIME-OF-
DAY- 07
HHMMSS(I6),LAT-DEG(F8.4),LONG-DEG(F8.4),TERRAINE-CLEAR-
METERS(F6.1),OUTSIDE 08
-AIR-PRESSURE-MMHG(F5.1),SURFACE-GEOLOGICAL-MAP-UNIT-CODE(A8),TOTAL-
MAG-FIELD-09
INTENSITY-nT(F7.1),RESIDUAL-MAG-FIELD-INTENSITY-nT(F7.1),DIURNAL-MAG-
INTENSITY10
-VARIATION-nT(F7.1),MAG-DEPTH-TO-BASEMENT-METERS(F7.1)| 11
1 7616,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +64+63-165-16216
W 17
Open file Report: GJBX-005(77) 18
Open file Contoured Map: GJM-007 19
Magnetic Data Tape: XS0595, file 18 20
Radiometric Data Tape: 464, file 10 TI 21
22
23
Editors Note: The above data header is for St. Michael Quadrangle. There are
similar headers for the other quadrangles in these projects. Those quadrangles
are: Black, Hooper Bay, Nunivak Island, Cape Mendenhall, Kwiguk, Marshall,
Baird Inlet, Kuskokwim Bay, Holy Cross, and Russian Mission.
FORMAT: N.U.R.E. #1, (NATIONAL URANIUM RESOURCE EVALUATION)
Contractor: Various Contractors
General: NOAA/NGDC has edited the NURE survey header records and flight line
header records so they conform to a similar format. No information has been
lost. Padded records were removed. No other changes have been made to the
data.
Contents:
Header Record
Columns Format Description
1 A40 Quadrangle Name as Project Identification
2 A20 Name of Subcontractor
3 I4 Approximate Date of Survey (Month,Year)
4 I3 Number of Flight Lines in Survey
Flight Line Records
Columns Format Description
1 I4 First Flight Line in Survey
2 I6 First Record Number of First Flight Line
3 I3 Julian Date(Day of Year) First Flight Line Data was
Collected
4 F8.4 Latitude of Ground Base Station to Four Decimal Places
in Degrees for First Flight Line
5 F8.4 Longitude of Ground Base Station to Four Decimal Places
in Degrees for First Flight Line
(SAME) (SAME) (SAME) Repeat of Items 1-5 for Second Flight Line in
Survey
(SAME) (SAME) (SAME) Repeat of items 1-5 for nth Flight Line in
Survey
Format for Magnetic Data Records
Columns Format Description
1 I1 Aerial System Identification Code
2 I4 Flight Line Number
3 I6 Record Identification Number
4 I6 GMT Time of Day (HHMMSS)
5 F8.4 Latitude to Four Decimal Places in Degrees
6 F8.4 Longitude to Four Decimal Places in Degrees
7 F6.1 Terrain Clearance to One Decimal Place in Meters
8 F5.1 Outside Air Pressure to One Decimal Place in MMHG
9 A8 Surface Geologic Map Unit Code
10 F7.1 Total Magnetic Field Intensity to One Decimal Place in
Gammas
11 F7.1 Residual (IGRF Removed) Magnetic Field Intensity to One
Decimal Place in Gammas
12 F7.1 Diurnal Magnetic Intensity Variation to One Decimal
Place in Gammas
13 F7.1 Magnetic Depth-To-Basement to One Decimal Place in
Meters (if Required)
Survey Number: NURE6018
Format Acronym: ARO8
NGDC File Number: 0420-499
Params: F R
Data Rec'd @NGDC (YYMMDD): 890000
Contributing Institution: DOE - Flown by Texas Instruments
Country: USA
Platform Name: Douglas Super DC-3
Code: 3
Platform Type: PLANE
Chief Scientist(s): DOE - Bendix Field Engineering
Project: Nunivak Island, Alaska
Start Date (YYMMDD): 760604
Survey Departure Airport:
End Date (YYMMDD): 760622
Survey Arrival Airport:
Flight Line Spacings: E-W: 6 miles
Magnetometor(s) Used: proton precession
Aircraft Altitude: 400 ft. AG
Aircraft Velocity: 150 mph
Sampling Rates Per Second: 1.8
Sensor Tow Distance: 100 ft.
Reference Field: IGRF
Total Observations: 3479
Magnetometor Sensitivity: ?
Bounding Limits:
Top Latitude : +61
Bottom Latitude: +60
Left Longitude : -168
Right Longitude: -165
Open file Report: GJBX-005(77)
Open file Contoured Map: GJM-011
Magnetic Data Tape: XS0595, file 13
Radiometric Data Tape: 464, file 14 TI
Data records are Longitude (degrees), Latitude (degrees), Mag (nT), Flight
elevation (meters).
Mag values are total field in nanoTeslas.
***********************************************************
Project No: 6019
Name: Taylor Mountains
Date Flown: 05/1976-08/1976
Altitude: 400 feet Above Ground
Spacing: 6 miles, E-W
Merge Priority: 35
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Texas Instruments, Inc., 1977,Aerial gamma-ray and magnetic survey
of the Bethel and Yukon areas, Alaska: U.S. Energy Research and
Development Administration, Grand Junction Office Report GJBX-005(77),
16 vols.
Notes:
1) Base station is NOT available for this survey.
2) Tie Line 612 was not used in preparation of grids and was removed from this
data set.
3) DGRF used FLTSURF and 76/06/21 date.
4) Processing Notes:
+55 nT datum shift applied
Decorrugation: None
Original "Info" file (edited):
Project no. 6019
Name: Taylor Mountains
Flown by: Texas Instruments
Number of line miles: 1400
Instrument: GeoMetric G-803 proton magnetometer
National Geophysical Data Center (NGDC) data header:
1NURE6019TG04-0420-539 F R 890000DOE - Flown by Texas Instruments 01
USA Douglas Super DC-3 3PLANE DOE - Bendix Field Engineering 02
Taylor Mountains, Alaska 03
760620 760625 04
E-W: 6 miles proton precession 05
400 ft. AG 150 mph 1.8100 ft.IGRF 18538? 06
AERIAL-SYS-ID-CODE(I1),FLIGHT-LINE-NUM(I4),RECORD-ID-NUM(I6),GMT-TIME-OF-
DAY- 07
HHMMSS(I6),LAT-DEG(F8.4),LONG-DEG(F8.4),TERRAINE-CLEAR-
METERS(F6.1),OUTSIDE 08
-AIR-PRESSURE-MMHG(F5.1),SURFACE-GEOLOGICAL-MAP-UNIT-CODE(A8),TOTAL-
MAG-FIELD-09
INTENSITY-nT(F7.1),RESIDUAL-MAG-FIELD-INTENSITY-nT(F7.1),DIURNAL-MAG-
INTENSITY10
-VARIATION-nT(F7.1),MAG-DEPTH-TO-BASEMENT-METERS(F7.1)| 11
1 7615,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +61+60-159-15616
W 17
Open file Report: GJBX-005(77) 18
Open file Contoured Map: GJM-029 19
Magnetic Data Tape: XS0595, file 19 20
Radiometric Data Tape: 464, file 22 TI 21
22
23
Data records are Longitude (degrees), Latitude (degrees), Mag (nT), Flight
elevation (ft)
Mag values are total field in nanoTeslas.
***********************************************************
Project No: 6020a, 6020b
Name: Nushagak Bay-Naknek
Date Flown: 05/1976-08/1976
Altitude: 400 feet Above Ground
Spacing: 6 miles, E-W
Merge Priority: 60
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Texas Instruments, Inc., 1977,Aerial gamma-ray and magnetic survey
of the Bethel and Yukon areas, Alaska: U.S. Energy Research and
Development Administration, Grand Junction Office Report GJBX-005(77),
16 vols.
Notes:
1) Base station is NOT available for these surveys.
2) Merged flightlines from 6020a & 6020b, processed as one survey.
3) DGRF used FLTSURF and 76/05/28 date.
4) Processing Notes:
-920 nT datum shift applied
Decorrugation: None
Original "Info" files (edited):
Project no. 6020
Name: Nushagak Bay
Flown by: Texas Instruments
Number of line miles: 1100
Instrument: GeoMetrics G-803 proton magnetometer
National Geophysical Data Center (NGDC) data headers:
1NUR6020ATG04-0420-552 F R 890000DOE - Flown by Texas Instruments 01
USA Douglas Super DC-3 3PLANE DOE - Bendix Field Engineering 02
Naknek, Alaska 03
760527 760528 04
E-W: 6 miles proton precession 05
400 ft. AG 150 mph 1.8100 ft.IGRF 10332? 06
AERIAL-SYS-ID-CODE(I1),FLIGHT-LINE-NUM(I4),RECORD-ID-NUM(I6),GMT-TIME-OF-
DAY- 07
HHMMSS(I6),LAT-DEG(F8.4),LONG-DEG(F8.4),TERRAINE-CLEAR-
METERS(F6.1),OUTSIDE 08
-AIR-PRESSURE-MMHG(F5.1),SURFACE-GEOLOGICAL-MAP-UNIT-CODE(A8),TOTAL-
MAG-FIELD-09
INTENSITY-nT(F7.1),RESIDUAL-MAG-FIELD-INTENSITY-nT(F7.1),DIURNAL-MAG-
INTENSITY10
-VARIATION-nT(F7.1),MAG-DEPTH-TO-BASEMENT-METERS(F7.1)| 11
1 7515,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +59+58-158-15616
W05157 17
Open file Report: GJBX-005(77) 18
Open file Contoured Map: GJM-022 19
Magnetic Data Tape: XS0591, file 13 20
Radiometric Data Tape: 464, file 18 TI 21
22
1NUR6020BTG04-0420-537 F R 890000DOE - Flown by Texas Instruments 01
USA Douglas Super DC-3 3PLANE DOE - Bendix Field Engineering 02
Nushagak Bay, Alaska 03
760527 760528 04
E-W: 6 miles proton precession 05
400 ft. AG 150 mph 1.8100 ft.IGRF 4515? 06
AERIAL-SYS-ID-CODE(I1),FLIGHT-LINE-NUM(I4),RECORD-ID-NUM(I6),GMT-TIME-OF-
DAY- 07
HHMMSS(I6),LAT-DEG(F8.4),LONG-DEG(F8.4),TERRAINE-CLEAR-
METERS(F6.1),OUTSIDE 08
-AIR-PRESSURE-MMHG(F5.1),SURFACE-GEOLOGICAL-MAP-UNIT-CODE(A8),TOTAL-
MAG-FIELD-09
INTENSITY-nT(F7.1),RESIDUAL-MAG-FIELD-INTENSITY-nT(F7.1),DIURNAL-MAG-
INTENSITY10
-VARIATION-nT(F7.1),MAG-DEPTH-TO-BASEMENT-METERS(F7.1)| 11
1 7515,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +59+58-160-15816
W 17
Open file Report: GJBX-005(77) 18
Open file Contoured Map: GJM-033 19
Magnetic Data Tape: XS0595, file 4 20
Radiometric Data Tape: 464, file 21 TI 21
22
Data records are Longitude (degrees), Latitude (degrees), Mag (nT), Flight
elevation (meters).
***********************************************************
Project No: 6023
Name: Cook Inlet (Tyonek)
Date Flown: 06/1976-07/1977
Altitude: 400 feet Above Ground
Spacing: 6 miles, E-W
Merge Priority:
References:
1) LK&B Resources, Inc., 1978, NURE aerial gamma-ray and magnetic
reconnaissance survey, Cook Inlet, Alaska: U.S. Department of Energy,
Grand Junction Office Report GJBX-108(78), 7 vols.
Notes:
1) "Flight elevation" listed below in original info is height above ground.
2) Quality poor.
3) Data were filtered with a 3.5 km. low pass filter prior to gridding.
4) Since the survey was flown at 400' nominal height, and the merged grid was
merged at 1000 feet, profile data for the MAG_MERGE channel were accordingly
upward continued before adjusting them to the merged grid.
5) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid:
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the corresponding grid.
Where composite data were missing on the whole length of the profiles, a first
order trend of the profile data was removed in the final composite channel.
Original "Info" file (edited):
Project no. 6023
Name: Cook Inlet (Toynek)
Flown by: LKB Resources
Number of line miles: 5753 (for all quadrangles)
Instrumentation: Modified ASQ-10 fluxgate magnetometer
NOTES 29 July 1993:
The original ascii data file tyonek.nure containing NURE mag data for the
6023 survey (LKB Resources, Inc) was provided by Richard W. Saltus (USGS).
The original data file contained the following:
FORMAT: N.U.R.E. #1, (NATIONAL URANIUM RESOURCE EVALUATION)
Format for Magnetic Data Records
Columns Format Description
1 I1 Aerial System Identification Code
2 I4 Flight Line Number
3 I6 Record Identification Number
4 I6 GMT Time of Day (HHMMSS)
5 F8.4 Latitude to Four Decimal Places in Degrees
6 F8.4 Longitude to Four Decimal Places in Degrees
7 F6.1 Terrain Clearance to One Decimal Place in Meters
8 F5.1 Outside Air Pressure to One Decimal Place in MMHG
9 A8 Surface Geologic Map Unit Code
10 F7.1 Total Magnetic Field Intensity to One Decimal Place
in Gammas
11 F7.1 Residual (IGRF Removed) Magnetic Field Intensity to
One Decimal Place in Gammas
12 F7.1 Diurnal Magnetic Intensity Variation to One Decimal
Place in Gammas (not available in this data set)
13 F7.1 Magnetic Depth-To-Basement to One Decimal Place in
Meters (if Required) (not available)
***********************************************************
Project No: 6023d, 6023e (combined)
Name: Cook Inlet (Seldovia, Kenai)
Date Flown: 06/1976-07/1976
Altitude: 400 feet Above Ground
Spacing: 6.0 miles, E-W
Merge Priority: 40 (6023d), 41 (6023e)
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) LK&B Resources, Inc., 1978, NURE aerial gamma-ray and magnetic
reconnaissance survey, Cook Inlet, Alaska: U.S. Department of Energy,
Grand Junction Office Report GJBX-108(78), 7 vols.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 76/07/04 date, and FLTSURF channel for elevation.
3) All "dropouts" (defined as < 50000 nT) in the original MAG_RAW were
changed to dummys for processing.)
4) Original 6023d & 6023e flight line data were combined and re-divided into
E(ast) and W(est) surveys for processing.
5) Processing Notes:
+70 nT datum shift applied
Tilted and upward continued
Decorrugation: None
Original "Info" files (edited):
Project no. 6023
Project name: Cook Inlet
Flown by: LKB Resources
Number of line miles: 5753 (for all quadrangles)
Instrument: Modified ASQ-10 fluxgate magnetometer
National Geophysical Data Center (NGDC) data headers:
1NUR6023DTG04-0420-572 F R 890000DOE - Flown by LKB Resources 01
USA Sikorsky S58T 3HELIO DOE - Bendix Field Engineering 02
Seldovia, Alaska 03
760704 760709 04
E-W: 6 miles ASQ-10 fluxgate modified 05
400 ft. AG 108 mph 2 stingerIGRF 65 133670.1nT 06
07
08
09
10
11
3 7514,7515,7615,9999, , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +61+59-154-14916
W 17
Open file Report: GJBX-108(78) 18
Open file Contoured Map: GJM-021 19
Magnetic Data Tape: XS0583, file 15 20
Radiometric Data Tape: 645, file 4 21
22
1NUR6023ETG04-0420-573 F R 890000DOE - Flown by LKB Resources 01
USA Sikorsky S58T 3HELIO DOE - Bendix Field Engineering 02
Kenai, Alaska 03
760630 760708 04
E-W: 6 miles ASQ-10 fluxgate modified 05
400 ft. AG 108 mph 2 stingerIGRF 65 216660.1nT 06
AERIAL-SYS-ID-CODE(I1),FLIGHT-LINE-NUM(I4),RECORD-ID-NUM(I6),RECORD-ID-
NUMBER 07
(I6),LAT-DEG(F8.4),LONG-DEG(F8.4),TERRAINE-CLEAR-METERS(F6.1),OUTSIDE 08
-AIR-PRESSURE-MMHG(F5.1),SURFACE-GEOLOGICAL-MAP-UNIT-CODE(A8),TOTAL-
MAG-FIELD-09
INTENSITY-nT(F7.1),RESIDUAL-MAG-FIELD-INTENSITY-nT(F7.1),DIURNAL-MAG-
INTENSITY10
-VARIATION-nT(F7.1),MAG-DEPTH-TO-BASEMENT-METERS(F7.1)| 11
3 7515,7614,7615,9999, , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +62+59-154-14916
W 17
Open file Report: GJBX-108(78) 18
Open file Contoured Map: GJM- 19
Magnetic Data Tape: XS0233, file 16 20
Radiometric Data Tape: 299, file 7 21
22
***********************************************************
Project No: 6025a
Name: Chugach-Yakutat (Yukutat)
Date Flown: 08/1976-08/1977
Altitude: 400 feet Above Ground
Spacing: 6 miles, E-W
Merge Priority: 38
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) LK&B Resources Inc., 1978, NURE aerial gamma-ray and magnetic
reconnaissance survey, Chugach/Yakutat area, Alaska: U.S. Department
of Energy, Grand Junction Office Report GJBX-127(78), 7 vols.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used FLTSURF and 77/08/02 date.
3) All "dropouts" (defined as < 50000 nT) in the original MAG_RAW were
changed to dummys for processing.
4) HEIGHT was missing for lines 52.1, 53.1, 55.1, and 56.1. We inserted
the nominal terrain separation of 122 meters (400 ft.) in those lines.
5) Processing Notes:
-3236 nT datum shift applied
Decorrugation: None
Original "Info" file (edited):
Project no. 6025
Name: Chugach-Yakutat
Flown by: LKB Resources
Number of line miles: 3680 (for all quadrangles)
Instrument: Modified ASQ-10 fluxgate magnetometer
National Geophysical Data Center (NGDC) data header:
1NUR6025ATG04-0420-620 F R 890000DOE - Flown by LKB Resources 01
USA Bell 205A-1&Sikorsky 3HELIO DOE - Bendix Field Engineering 02
Yakutak, Alaska 03
770731 770803 04
E-W: 6 miles V-85 Varian & ASQ-10 fluxgate modified05
400 ft. AG 108 mph 2 stingerIGRF 65 120220.1nT 06
AERIAL-SYS-ID-CODE(I1),FLIGHT-LINE-NUM(I4),RECORD-ID-NUM(I6),RECORD-ID-
NUMBER 07
(I6),LAT-DEG(F8.4),LONG-DEG(F8.4),TERRAINE-CLEAR-METERS(F6.1),OUTSIDE 08
-AIR-PRESSURE-MMHG(F5.1),SURFACE-GEOLOGICAL-MAP-UNIT-CODE(A8),TOTAL-
MAG-FIELD-09
INTENSITY-nT(F7.1),RESIDUAL-MAG-FIELD-INTENSITY-nT(F7.1),DIURNAL-MAG-
INTENSITY10
-VARIATION-nT(F7.1),MAG-DEPTH-TO-BASEMENT-METERS(F7.1)| 11
2 7513,7613,9999, , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +61+58-140-13716
W 17
Open file Report: GJBX-127(78) 18
Open file Contoured Map: GJM-026 19
Magnetic Data Tape: XS0233, file 17 20
Radiometric Data Tape: 403, file 3 21
22
Data records are Longitude (degrees), Latitude (degrees), Mag (nT), Flight
elevation (meters)
Mag values are total field in nanoTeslas.
***********************************************************
Project No: 6025c
Name: Chugach-Yukutat (Bering Glacier)
Date Flown: 08/1976-08/1977
Altitude: 400 feet Above Ground
Spacing: 6 miles, E-W
Merge Priority: 50
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) LK&B Resources Inc., 1978, NURE aerial gamma-ray and magnetic
reconnaissance survey, Chugach/Yakutat area, Alaska: U.S. Department
of Energy, Grand Junction Office Report GJBX-127(78), 7 vols.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used FLTSURF and 77/08/05 date.
3) Processing Notes:
+85 nT datum shift applied
Decorrugation: None
Original "Info" file (edited):
Project no. 6025
Name: Chugach-Yukutat
Flown by: LKB Resources
Number of line miles: 3680 (for all quadrangles)
Instrument: Modified ASQ-10 fluxgate magnetometer
National Geophysical Data Center (NGDC) data header:
1NUR6025CTG04-0420-609 F R 890000DOE - Flown by LKB Resources 01
USA Bell 205A-1&Sikorsky 3HELIO DOE - Bendix Field Engineering 02
Bering Glacier, Alaska 03
770721 770818 04
E-W: 6 miles V-85 Varian & ASQ-10 fluxgate modified05
400 ft. AG 108 mph 2 stingerIGRF 65 155340.1nT 06
AERIAL-SYS-ID-CODE(I1),FLIGHT-LINE-NUM(I4),RECORD-ID-NUM(I6),GMT-TIME-OF-
DAY- 07
HHMMSS(I6),LAT-DEG(F8.4),LONG-DEG(F8.4),TERRAINE-CLEAR-
METERS(F6.1),OUTSIDE 08
-AIR-PRESSURE-MMHG(F5.1),SURFACE-GEOLOGICAL-MAP-UNIT-CODE(A8),TOTAL-
MAG-FIELD-09
INTENSITY-nT(F7.1),RESIDUAL-MAG-FIELD-INTENSITY-nT(F7.1),DIURNAL-MAG-
INTENSITY10
-VARIATION-nT(F7.1),MAG-DEPTH-TO-BASEMENT-METERS(F7.1)| 11
2 7514,7614,9999, , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +62+59-145-14016
W 17
Open file Report: GJBX-127(78) 18
Open file Contoured Map: GJM-031 19
Magnetic Data Tape: XS0522, file 1 20
Radiometric Data Tape: 498, file 4 21
22
Data records are Longitude (degrees), Latitude (degrees), Mag (nT), Flight
elevation (meters)
Mag values are total field in nanoTeslas.
***********************************************************
Project No: 6026a
Name: Southeastern Alaska (Skagway)
Date Flown: 07/1977-09/1977
Altitude: 400 feet Above Ground
Spacing: 6.0 miles, E-W
Merge Priority: 51
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) LK&B Resources, Inc., 1979, NURE aerial gamma-ray and magnetic
reconnaissance survey, Southeastern area, Alaska: U.S. Department
of Energy, Grand Junction Office Report GJBX-048(79), 15 vols.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 77/08/21 date, and FLTSURF channel for elevation.
3) All "dropouts" (defined as < 50000 nT) in the original MAG_RAW were
changed to dummys for processing.
4) Lines 52.1, 53.1, 56.1, and Tie Lines 207.0, & 209.1 had zero values for
the entire MAG_RAW channel and were deleted from the database.
5) Line 54.0 has anomalous values for MAG_RAW from fid #504 to fid #530, these
values were retained, but are probably incorrect.
5) Processing Notes:
-216 nT datum shift applied
Decorrugation: None
Original "Info" file (edited):
Project no. 6026
Name: Souteastern Alaska
Flown by: LKB Resources
Number of line miles: 7683 (for all quadrangles)
Instrument: Modified ASQ-10 fluxgate magnetometer
National Geophysical Data Center (NGDC) data header:
1NUR6026ATG04-0420-623 F 890000DOE - Flown by LKB Resources 01
USA Bell 205A-1&Sikorsky 3HELIO DOE - Bendix Field Engineering 02
Skagway, Alaska 03
770731 770912 04
E-W: 6 miles V-85 Varian & ASQ-10 fluxgate modified05
400 ft. AG 108 mph 2 stingerIGRF 65 107540.1nT 06
07
08
09
10
11
1 7513,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +60+58-139-13416
W 17
Open file Report: GJBX-048(79) (includes contoured maps) 18
Magnetic Data Tape: XS0583, file 2 19
Radiometric Data Tape: 501, file 4 20
21
***********************************************************
Project No: 6026f, 6026g, 6026h (combined)
Name: Southeastern Alaska (Sitka, Sumdum, & Port Alexander)
Date Flown: 07/1977-09/1977
Altitude: 400 feet Above Ground
Spacing: 6.0 miles, E-W
Merge Priority: 51
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) LK&B Resources, Inc., 1979, NURE aerial gamma-ray and magnetic
reconnaissance survey, Southeastern area, Alaska: U.S. Department
of Energy, Grand Junction Office Report GJBX-048(79), 15 vols.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 77/08/29 date, and FLTSURF channel for elevation.
3) Combined areas 6026f, 6026g, and 6026h.
4) All "dropouts" (defined as < 50000 nT) in the original MAG_RAW were
changed to dummys for processing.
5) Lines 68.x-72.x, 73.1, 74.1, 75.1, & 75.2 had zero values for
the entire MAG_RAW channel and were deleted from the database.
6) Processing Notes:
+3665 nT datum shift applied
Decorrugation: None
Original "Info" files (edited):
Project no. 6026
Name: Southeastern Alaska
Flown by: LKB Resources
Number of lines miles: 7683 (for all quadrangles)
Instrument: Modified ASQ-10 fluxgate magnetometer
National Geophysical Data Center (NGDC) data header:
1NUR6026FTG04-0420-624 F 890000DOE - Flown by LKB Resources 01
USA Bell 205A-1&Sikorsky 3HELIO DOE - Bendix Field Engineering 02
Sitka, Alaska 03
770814 770923 04
E-W: 6 miles V-85 Varian & ASQ-10 fluxgate modified05
400 ft. AG 108 mph 2 stingerIGRF 65 219410.1nT 06
07
08
09
10
11
1 7513,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +59+56-137-13316
W 17
Open file Report: GJBX-048(79) (includes contoured maps) 18
Magnetic Data Tape: XS0565, file 6 19
Radiometric Data Tape: 503, file 4 20
21
1NUR6026GTG04-0420-631 F 890000DOE - Flown by LKB Resources 01
USA Bell 205A-1&Sikorsky 3HELIO DOE - Bendix Field Engineering 02
Sumdum, Alaska 03
770806 770908 04
E-W: 6 miles V-85 Varian & ASQ-10 fluxgate modified05
400 ft. AG 108 mph 2 stingerIGRF 65 122260.1nT 06
07
08
09
10
11
1 7513,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +58+56-135-13216
W 17
Open file Report: GJBX-048(79) 18
Open file Contoured Map: GJM-020 19
Magnetic Data Tape: XS0203, file 3 20
Radiometric Data Tape: 503, file 6 21
22
1NUR6026HTG04-0420-625 F R 890000DOE - Flown by LKB Resources 01
USA Bell 205A-1&Sikorsky 3HELIO DOE - Bendix Field Engineering 02
Port Alexander, Alaska 03
770805 770825 04
E-W: 6 miles V-85 Varian & ASQ-10 fluxgate modified05
400 ft. AG 108 mph 2stingerIGRF 65 9306 0.1nT06
AERIAL-SYS-ID-CODE(I1),FLIGHT-LINE-NUM(I4),RECORD-ID-NUM(I6),GMT-TIME-OF-
DAY- 07
HHMMSS(I6),LAT-DEG(F8.4),LONG-DEG(F8.4),TERRAINE-CLEAR-
METERS(F6.1),OUTSIDE 08
-AIR-PRESSURE-MMHG(F5.1),SURFACE-GEOLOGICAL-MAP-UNIT-CODE(A8),TOTAL-
MAG-FIELD-09
INTENSITY-nT(F7.1),RESIDUAL-MAG-FIELD-INTENSITY-nT(F7.1),DIURNAL-MAG-
INTENSITY10
-VARIATION-nT(F7.1),MAG-DEPTH-TO-BASEMENT-METERS(F7.1)| 11
1 7513,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +57+56-136-13316
W 17
Open file Report: GJBX-048(79) (includes contoured maps) 18
Magnetic Data Tape: XS0664, file 2 19
Radiometric Data Tape: 353, file 2 20
21
***********************************************************
Project No: 6035
Name: Eagle-Talkeetna (Mount McKinley)
Date Flown: 06/1977-09/1977
Altitude: 400 feet Above Ground
Spacing: 6 miles, E-W
Merge Priority:
References:
1) Texas Instruments, Inc., 1978, Aerial radiometric and magnetic
reconnaissance survey of the Eagle-Dillingham area, Alaska: U.S.
Department of Energy, Grand Junction Office Report GJBX-113(78),
14 vols.
Notes:
1) "Flight elevation" listed below in original info is height above ground.
2) Quality poor.
3) Data were filtered with a 3.5 km. low pass filter prior to gridding.
4) Since the survey was flown at 400' nominal height, and the merged grid was
merged at 1000 feet, profile data for the MAG_MERGE channel were accordingly
upward continued before adjusting them to the merged grid.
5) In order to preserve the much higher resolution along the measured
profiles, we have levelled the final residual magnetic field to the
composite or to the merged grid:
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the corresponding grid.
Original "Info" file (edited):
Project no. 6035
Name: Eagle-Talkeetna
Flown by: Texas Instruments
Number of lines miles: 12,392 (For all quadrangles)
Instrument: Proton magnetometer
Notes 29 July 1993:
The original ascii data file mtmckinley.nure containing NURE mag data for the
6035 survey (Texas Instruments, 1977) was provided by Richard W. Saltus
(USGS).
The original data file contained the following:
FORMAT: N.U.R.E. #1, (NATIONAL URANIUM RESOURCE EVALUATION)
Format for Magnetic Data Records
Columns Format Description
1 I1 Aerial System Identification Code
2 I4 Flight Line Number
3 I6 Record Identification Number
4 I6 GMT Time of Day (HHMMSS)
5 F8.4 Latitude to Four Decimal Places in Degrees
6 F8.4 Longitude to Four Decimal Places in Degrees
7 F6.1 Terrain Clearance to One Decimal Place in Meters
8 F5.1 Outside Air Pressure to One Decimal Place in MMHG
9 A8 Surface Geologic Map Unit Code
10 F7.1 Total Magnetic Field Intensity to One Decimal Place
in Gammas
11 F7.1 Residual (IGRF Removed) Magnetic Field Intensity to
One Decimal Place in Gammas
12 F7.1 Diurnal Magnetic Intensity Variation to One Decimal
Place in Gammas
13 F7.1 Magnetic Depth-To-Basement to One Decimal Place in
Meters (if Required) (not available)
***********************************************************
Project No: 6035j
Name: Eagle-Talkeetna (Charley River)
Date Flown: 06/1977-09/1977
Altitude: 400 feet Above Ground
Spacing: 6 miles, E-W
Merge Priority: 39
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Texas Instruments, Inc., 1978, Aerial radiometric and magnetic
reconnaissance survey of the Eagle-Dillingham area, Alaska: U.S.
Department of Energy, Grand Junction Office Report GJBX-113(78),
14 vols.
Notes:
1) DGRF used FLTSURF and 77/07/01 date.
2) Processing Notes:
+29 nT datum shift applied
Decorrugation: None
Original "Info" file (edited):
Project no. 6035
Name: Eagle-Talkeetna
Flown by: Texas Instruments
Number of lines miles: 12,392 (for all quadrangles)
Instrument: Proton magnetometer
National Geophysical Data Center (NGDC) data header:
1NUR6035JTG04-0420-614 F R 890000DOE - Flown by Texas Instruments 01
USA Bell 212 3HELIO DOE - Bendix Field Engineering 02
Charley River, Alaska 03
770623 770710 04
E-W: 6 miles proton precession 05
400 ft. AG 70 mph 1 60 ft. IGRF 44395? 06
AERIAL-SYS-ID-CODE(I1),FLIGHT-LINE-NUM(I4),RECORD-ID-NUM(I6),GMT-TIME-OF-
DAY- 07
HHMMSS(I6),LAT-DEG(F8.4),LONG-DEG(F8.4),TERRAINE-CLEAR-
METERS(F6.1),OUTSIDE 08
-AIR-PRESSURE-MMHG(F5.1),SURFACE-GEOLOGICAL-MAP-UNIT-CODE(A8),TOTAL-
MAG-FIELD-09
INTENSITY-nT(F7.1),RESIDUAL-MAG-FIELD-INTENSITY-nT(F7.1),DIURNAL-MAG-
INTENSITY10
-VARIATION-nT(F7.1),MAG-DEPTH-TO-BASEMENT-METERS(F7.1)| 11
1 7614,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +66+65-144-14116
W 17
Open file Report: GJBX-113(78) 18
Open file Contoured Map: GJM-043 19
Magnetic Data Tape: XS0588, file 8 20
Radiometric Data Tape: 779, file 1 TI 21
22
Data records are Longitude (degrees), Latitude (degrees), Mag (nT), Flight
elevation (meters).
Mag values are total field in nanoTeslas.
***********************************************************
Project No: 6036
Name: Lime Hills-Lake Clark
Date Flown: 06/1977-09/1977
Altitude: 400 feet Above Ground
Spacing: 6 miles, E-W
Merge Priority:
References:
1) Texas Instruments, Inc., 1978, Aerial radiometric and magnetic
reconnaissance survey of the Eagle-Dillingham area, Alaska: U.S.
Department of Energy, Grand Junction Office Report GJBX-113(78),
14 vols.
Notes:
1) "Flight elevation" listed below in original info is height above ground.
2) Quality poor.
3) Data were filtered with a 3.5 km. low pass filter prior to gridding.
4) Since the survey was flown at 400' nominal height, and the merged grid was
merged at 1000 feet, profile data for the MAG_MERGE channel were accordingly
upward continued before adjusting them to the merged grid.
5) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid:
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the merged grid.
*By subtracting from the profile data, the first order trend of the difference
between profile data and data extracted from the composite grid.
Where composite data were missing on the whole length of the profiles, a first
order trend of the profile data was removed in the final composite channel.
Original "Info" file (edited):
Project no. 6036
Name: Lime Hills-Lake Clark
Flown by: Texas Instruments
Number of line miles: 2775
Instrument: Proton magnetometer
Notes 29 July 1993:
The original ascii data file "limehills.nure" containing NURE mag data for the
6036 survey (Texas Instruments, 1977) was provided by Richard W. Saltus (USGS).
The original data file contained the following:
FORMAT: N.U.R.E. #1, (NATIONAL URANIUM RESOURCE EVALUATION)
Format for Magnetic Data Records
Columns Format Description
1 I1 Aerial System Identification Code
2 I4 Flight Line Number
3 I6 Record Identification Number
4 I6 GMT Time of Day (HHMMSS)
5 F8.4 Latitude to Four Decimal Places in Degrees
6 F8.4 Longitude to Four Decimal Places in Degrees
7 F6.1 Terrain Clearance to One Decimal Place in Meters
8 F5.1 Outside Air Pressure to One Decimal Place in MMHG
9 A8 Surface Geologic Map Unit Code
10 F7.1 Total Magnetic Field Intensity to One Decimal Place
in Gammas
11 F7.1 Residual (IGRF Removed) Magnetic Field Intensity to
One Decimal Place in Gammas
12 F7.1 Diurnal Magnetic Intensity Variation to One Decimal
Place in Gammas
13 F7.1 Magnetic Depth-To-Basement to One Decimal Place in
Meters (if Required) (not available)
***********************************************************
Project No: 6037
Name: Dillingham
Date Flown: 06/1977-09/1977
Altitude: 400 feet Above Ground
Spacing: 6 miles, E-W
Merge Priority: 37
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Texas Instruments, Inc., 1978, Aerial radiometric and magnetic
reconnaissance survey of the Eagle-Dillingham area, Alaska: U.S.
Department of Energy, Grand Junction Office Report GJBX-113(78),
14 vols.
Notes:
1) DGRF used FLTSURF and 77/06/14 date.
2) Processing Notes:
+45 nT datum shift applied
Decorrugation: None
Original "Info" file (edited):
Project no. 3037
Name: Dillingham
Flown by: Texas Instruments
Number of line miles: 1509
Instrument: Proton magnetometer
National Geophysical Data Center (NGDC) data header:
1NURE6037TG04-0420-538 F R 890000DOE - Flown by Texas Instruments 01
USA Bell 212 3HELIO DOE - Bendix Field Engineering 02
Dillingham, Alaska 03
770613 770615 04
E-W: 6 miles proton precession 05
400 ft. AG 70 mph 1 60 ft. IGRF 54199? 06
AERIAL-SYS-ID-CODE(I1),FLIGHT-LINE-NUM(I4),RECORD-ID-NUM(I6),GMT-TIME-OF-
DAY- 07
HHMMSS(I6),LAT-DEG(F8.4),LONG-DEG(F8.4),TERRAINE-CLEAR-
METERS(F6.1),OUTSIDE 08
-AIR-PRESSURE-MMHG(F5.1),SURFACE-GEOLOGICAL-MAP-UNIT-CODE(A8),TOTAL-
MAG-FIELD-09
INTENSITY-nT(F7.1),RESIDUAL-MAG-FIELD-INTENSITY-nT(F7.1),DIURNAL-MAG-
INTENSITY10
-VARIATION-nT(F7.1),MAG-DEPTH-TO-BASEMENT-METERS(F7.1)| 11
1 7515,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +60+59-159-15616
W05237 17
Open file Report: GJBX-113(78) 18
Open file Contoured Map: GJM-024 19
Magnetic Data Tape: XS0588, file 14 20
Radiometric Data Tape: 776, file 2 TI 21
22
***********************************************************
Project No: 6121
Name: West Central Alaska
Date Flown: 07/1979-09/1979
Altitude: 400 feet Above Ground
Spacing: 6 miles, E-W
Merge Priority:
References:
1) Aero Service Corp., 1980, Airborne gamma-ray spectrometer and
magnetometer survey, Nulato Quadrangle (Alaska): U.S. Department
of Energy, Grand Junction Office Report GJBX-073(80), 2 vols.
2) Aero Service Corp., 1980, Airborne gamma-ray spectrometer and
magnetometer survey, Ruby Quadrangle (Alaska): U.S. Department of
Energy, Grand Junction Office Report GJBX-075(80), 2 vols.
3) Aero Service Corp., 1980, Airborne gamma-ray spectrometer and
magnetometer survey, McGrath Quadrangle (Alaska): U.S. Department
of Energy, Grand Junction Office Report GJBX-077(80), 2 vols.
4) Aero Service Corp., 1980, Airborne gamma-ray spectrometer and
magnetometer survey, Ophir Quadrangle (Alaska): U.S. Department
of Energy, Grand Junction Office Report GJBX-078(80), 2 vols.
5) Aero Service Corp., 1980, Airborne gamma-ray spectrometer and
magnetometer survey, Sleetmute Quadrangle (Alaska):U.S. Department
of Energy, Grand Junction Office Report GJBX-079(80), 2 vols.
6) Aero Service Corp., 1980, Airborne gamma-ray spectrometer and
magnetometer survey, Iditarod Quadrangle (Alaska): U.S. Department
of Energy, Grand Junction Office Report GJBX-080(80), 2 vols.
7) Aero Service Corp., 1980, Airborne gamma-ray spectrometer and
magnetometer survey, Kantishna River Quadrangle (Alaska), U.S.
Department of Energy, Grand Junction Office Report GJBX-094(80),
2 vols.
Notes:
1) This is an integrated data set consisting in 7 original parts:
Sleemute, McGrath, Iditarod, Ophir, Nulato, Ruby and Kantishna River. Data
have been all imported into one gdb, namely 6121.gdb.
2) "Flight elevation" listed below in original info is height above ground.
3) Quality poor.
4) IGRF removed in original data set.
5) Data were filtered with a 3.5 km. low pass filter prior to gridding.
6) Since the survey was flown at 400' nominal height, and the merged grid was
merged at 1000 feet, profile data for the mag_merge channel were accordingly
upward continued before adjusting them to the merged grid.
6) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid:
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the merged grid.
*By subtracting from the profile data, the first order trend of the difference
between profile data and data extracted from the composite grid.
Where composite data were missing on the whole length of the profiles, a first
order trend of the profile data was removed in the final composite channel.
Original "Info" file (edited):
Project no. 6121
Name: West-central Alaska
Flown by: Aero Service
Number of line miles: 13,273 (for all quadrangles)
Instrument: Geometrics G-803 proton magnetometer
Notes 29 July 1993:
The original ascii data files containing NURE mag data for the seven parts of
the 6121 survey (Aero Service /1979) was provided by Richard W. Saltus (USGS).
The original data files contained the following:
FORMAT: N.U.R.E. #1, (NATIONAL URANIUM RESOURCE EVALUATION)
Format for Magnetic Data Records
Columns Format Description
1 I1 Aerial System Identification Code
2 I4 Flight Line Number
3 I6 Record Identification Number
4 I6 GMT Time of Day (HHMMSS)
5 F8.4 Latitude to Four Decimal Places in Degrees
6 F8.4 Longitude to Four Decimal Places in Degrees
7 F6.1 Terrain Clearance to One Decimal Place in Meters
8 F5.1 Outside Air Pressure to One Decimal Place in MMHG
9 A8 Surface Geologic Map Unit Code
10 F7.1 Total Magnetic Field Intensity to One Decimal Place
in Gammas
11 F7.1 Residual (IGRF Removed) Magnetic Field Intensity to
One Decimal Place in Gammas
12 F7.1 Diurnal Magnetic Intensity Variation to One Decimal
Place in Gammas
13 F7.1 Magnetic Depth-To-Basement to One Decimal Place in
Meters (if Required) (not available)
***********************************************************
Project No: 6121a, 6121c
Name: Norton Bay (6121a), Unalakleet (6121c)
Date Flown: 07/1979-09/1979
Altitude: 400 feet Above Ground
Spacing: 6 miles, E-W
Merge Priority: 35
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Aero Service Corp., 1980, Airborne gamma-ray spectrometer and
magnetometer survey, Norton Bay Quadrangle (Alaska): U.S. Department
of Energy, Grand Junction Office Report GJBX-072(80), 2 vols.
2) Aero Service Corp., 1980, Airborne gamma-ray spectrometer and
magnetometer survey, Unalakleet Quadrangle (Alaska): U.S. Department
of Energy, Grand Junction Office Report GJBX-075(80), 2 vols.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used FLTSURF and 79/07/22 (6121a) & 79/08/22 (6121c) dates.
3) Combined 6121a & 6121c, processed as one survey.
4) All "dropouts" (<= zero values) in the original HEIGHT channel were
changed to dummys for processing (Lines 284 & 360).
5) Processing Notes:
+54 nT datum shift applied
Decorrugation: None
Original "Info" file (edited):
Project no. 6121
Name: West-central Alaska
Flown by: Aero Service
Number of line miles: 13273 (for all quadrangles)
Instrument: Geometrics G-803 proton magnetometer
National Geophysical Data Center (NGDC) data headers:
NGDC
1NUR6121ATG04-0420-529 F R 890000DOE - Flown by Aero Service and Carson 01
USA Sikorsky S58T 3HELIO DOE - Bendix Field Engineering 02
Norton Bay, Alaska 03
790712Galena, Alaska 790803Manley, Alaska 04
E-W: 6 miles GeoMetrics G-803 05
400 ft. AG 60.92 mph 75 ft. IGRF 75 308490.25nT 06
AERIAL-SYS-ID-CODE(I1),FLIGHT-LINE-NUM(I4),RECORD-ID-NUM(I6),GMT-TIME-OF-
DAY- 07
HHMMSS(I6),LAT-DEG(F8.4),LONG-DEG(F8.4),TERRAINE-CLEAR-
METERS(F6.1),OUTSIDE 08
-AIR-PRESSURE-MMHG(F5.1),SURFACE-GEOLOGICAL-MAP-UNIT-CODE(A8),TOTAL-
MAG-FIELD-09
INTENSITY-nT(F7.1),RESIDUAL-MAG-FIELD-INTENSITY-nT(F7.1),DIURNAL-MAG-
INTENSITY10
-VARIATION-nT(F7.1),MAG-DEPTH-TO-BASEMENT-METERS(F7.1)| 11
2 7615,7616,9999, , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +65+64-162-15916
W05235 17
Open File Report: GJBX-072(80) 18
Open File Contoured Map: GJM-042 19
Magnetic Data Tape: XS0117, file 9 20
21
1NUR6121CTG04-0420-528 F R 890000DOE - Flown by Aero Service and Carson 01
USA Sikorsky S58T 3HELIO DOE - Bendix Field Engineering 02
Unalakleet, Alaska 03
790821Galena, Alaska 790823Manley, Alaska 04
E-W: 6 miles GeoMetrics G-803 05
400 ft. AG 60.92 mph 75 ft. IGRF 362870.25nT 06
AERIAL-SYS-ID-CODE(I1),FLIGHT-LINE-NUM(I4),RECORD-ID-NUM(I6),GMT-TIME-OF-
DAY- 07
HHMMSS(I6),LAT-DEG(F8.4),LONG-DEG(F8.4),TERRAINE-CLEAR-
METERS(F6.1),OUTSIDE 08
-AIR-PRESSURE-MMHG(F5.1),SURFACE-GEOLOGICAL-MAP-UNIT-CODE(A8),TOTAL-
MAG-FIELD-09
INTENSITY-nT(F7.1),RESIDUAL-MAG-FIELD-INTENSITY-nT(F7.1),DIURNAL-MAG-
INTENSITY10
-VARIATION-nT(F7.1),MAG-DEPTH-TO-BASEMENT-METERS(F7.1)| 11
2 7615,7616,9999, , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +64+63-162-15916
W 17
Open File Report: GJBX-074(80) 18
Open File Contoured Map: GJM-208 19
Magnetic Data Tape: XS0135, file 5 20
21
Data records are Longitude (degrees), Latitude (degrees), Mag (nT), Flight
elevation (meters).
Mag values are total field in nanoTeslas.
***********************************************************
Project No: 6169c
Name: Meade River
Date Flown: 07/1980
Altitude: 400 feet Above Ground
Spacing: 6.0 miles, E-W
Merge Priority: 48
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Aero Service Corp., 1980, Airborne gamma-ray spectrometer and
magnetometer survey, Meade River Quadrangle (Alaska): U.S. Department
of Energy, Grand Junction Office Report GJBX-297(81), 2 vols.
Notes:
1) DGRF used 80/07/17 date, and FLTSURF channel for elevation.
2) Processing Notes:
+9 nT datum shift applied
Decorrugation: None
Original "Info" file (edited):
Project no. 6169
Name: Northern Alaska
Flown by: Aero Service
Number of line miles: 8835 (for all quadrangles)
Instrument: Geometrics G-803 proton magnetometer
National Geophysical Data Center (NGDC) data header:
1NUR6169CTG04-0420-549 F R 890000DOE - Flown by Aero Service Corp. 01
USA Douglas DC-3 3PLANE DOE - Bendix Field Engineering 02
Meade River, Alaska 03
800717Deadhorse, Alaska 800717Deadhorse, Alaska 04
E-W: 6 miles GeoMetrics G-803 05
400 ft. AG 90.2 mph 100 ft.IGRF 75 230350.25nT 06
AERIAL-SYS-ID-CODE(I1),FLIGHT-LINE-NUM(I4),RECORD-ID-NUM(I6),GMT-TIME-OF-
DAY- 07
HHMMSS(I6),LAT-DEG(F8.4),LONG-DEG(F8.4),TERRAINE-CLEAR-
METERS(F6.1),OUTSIDE 08
-AIR-PRESSURE-MMHG(F5.1),SURFACE-GEOLOGICAL-MAP-UNIT-CODE(A8),TOTAL-
MAG-FIELD-09
INTENSITY-nT(F7.1),RESIDUAL-MAG-FIELD-INTENSITY-nT(F7.1),DIURNAL-MAG-
INTENSITY10
-VARIATION-nT(F7.1),MAG-DEPTH-TO-BASEMENT-METERS(F7.1)| 11
1 7715,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +71+70-159-15616
W 17
Open File Report: GJBX-297(81) 18
Open File Contoured Map: GJM-509 19
Magnetic Data Tape: 232 file 6 20
21
***********************************************************
Project No: AK01
Name: Western Brooks Range Survey
Date Flown: 1958
Altitude: 5000 ft Barometric
Spacing: 16.5 miles, N-S
Merge Priority: 53
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Decker, John, and Karl, Susan, 1977, Preliminary aeromagnetic map of
the Brooks Range and Arctic Slope, Alaska: U.S. Geological Survey Open-
File Report 77-166E, scale 1:1,000,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 58/06/30 date, and FLTSURF channel for elevation.
3) Processing Notes:
+32 nT datum shift applied
Decorrugation: None
Original "Info" file (edited):
Project no.: AK01
Name: Western Brooks Range Survey
Flown by: Aero Service
Number of line miles: 1120
Instrument: Unknown
Digital data source: from computer cards found by Bob Morin, USGS, Menlo Park
History: This survey was flown as a speculative venture by Aero Service.
Dave Barnes, USGS, purchased the data originally.
Data format:
Flightline number
Longitude
Latitude
Total field anomaly, datum unknown
Total field
Height above terrain (meters) (all zero - no data)
Barometric altitude (meters) (all zero - no data)
Fiducial number
Year and dat (YYMMDD.0) (all zero - no data)
Fortran format:
(a8,f10.4,f9.4,f8.2,f9.2,3f8.2,f11.3)
***********************************************************
Project No: AK04
Name: Western Baird Mountains
Date Flown: 1970
Altitude: Probable 5000 ft Barometric
Spacing: Variable, N-S
Merge Priority: 52
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Decker, John, and Karl, Susan, 1977, Preliminary aeromagnetic map of
the Brooks Range and Arctic Slope, Alaska: U.S. Geological Survey Open-
File Report 77-166E, scale 1:1,000,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 70/06/30 date, and FLTSURF channel for elevation.
3) Processing Notes:
Decorrugation: None
+92 nT datum shift applied
Original "Info" file (edited):
Project no.: AK04
Name: Western Baird Mountains
Flown by: Scintrex
Number of line miles: unknown
Instrument: unknown
datum unknown
Digital data source: from computer cards found by Bob Morin, USGS, Menlo Park
History: This survey was contracted for by Dave Barnes, USGS, Menlo Park.
The survey was flown on flights to and from the SW Naval Pet.
Reserve survey (Project No. 3007B). Cost of the survey was
90 cents/mile. Dave Barnes recalls that the altitude specification
(5000 ft barometric) was chosen to match that of AK01 (1958
Aero Service survey).
Data format:
Flightline number
Longitude
Latitude
Total field anomaly, datum unknown
Total field
Height above terrain (meters) (all zero - no data)
Barometric altitude (meters) (all zero - no data)
Fiducial number
Year and dat (YYMMDD.0) (all zero - no data)
Fortran format:
(a8,f10.4,f9.4,f8.2,f9.2,3f8.2,f11.3)
***********************************************************
Project No: AK05
Name: Gulf of Alaska
Date Flown: 04/1970-05/1970
Altitude: 900 ft Barometric
Spacing: 0.5 to 4 miles, mostly E-W
Merge Priority: 33
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Taylor, P.T., and O'Neill, N.J., 1974, Results of an aeromagnetic survey
in the Gulf of Alaska: Journal of Geophysical Reseach, v. 79, no. 5,
p. 719-723.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 70/04/15 date, and FLTSURF channel for elevation.
3) Processing Notes:
+55 nT datum shift applied
Tilt removed in west 1/2 of area: -82.183815, -0.000109212, 0.000117964
Decorrugation: None
BTWR 0.000155
DCOS-Dir 280
DCOS-Deg 0.5
Original "Info" file (edited):
Project no.: AK05
Name: Gulf of Alaska
Flown by: U.S. Naval Oceanographic Office
Number of line miles:19,200
Instrument: Unknown
Digitized by: DIGIMAP (Esther Castellanos, December 1996)
Map scale: approx. 1:1,000,000
Datum: total field (no IGRF removed)
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Total Field (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
***********************************************************
Project No: AK07
Name: Seward Peninsula (Bendeleben & Candle)
Date Flown: 1971
Altitude: 1000 feet Above Ground
Spacing: 0.75 mile, E-W
Merge Priority:
References:
1) Cady, J.W., 1977, Aeromagnetic interpretation map of Seward
Peninsula, Alaska, USGS OF Rept. 77-796G, scale 1:1,000,000.
2) Alaska Division of Geological and Geophysical Surveys, 1973,
Aeromagnetic map, Southwest Selawik Quadrangle: Alaska Division
of Geological and Geophysical Surveys Open-File Report 1, scale
1:250,000.
3) Alaska Division of Geological and Geophysical Surveys, 1973,
Aeromagnetic map, South Teller Quadrangle: Alaska Division
of Geological and Geophysical Surveys Open-File Report 2, scale
1:250,000.
4) Alaska Division of Geological and Geophysical Surveys, 1973,
Aeromagnetic map, Bendeleben Quadrangle: Alaska Division
of Geological and Geophysical Surveys Open-File Report 3, scale
1:250,000.
5) Alaska Division of Geological and Geophysical Surveys, 1973,
Aeromagnetic map, Western Candle Quadrangle: Alaska Division
of Geological and Geophysical Surveys Open-File Report 4, scale
1:250,000.
6) Alaska Division of Geological and Geophysical Surveys, 1973,
Aeromagnetic map, Northeast Nome Quadrangle: Alaska Division
of Geological and Geophysical Surveys Open-File Report 5, scale
1:250,000.
7) Alaska Division of Geological and Geophysical Surveys, 1973,
Aeromagnetic map, Northern Solomon Quadrangle: Alaska Division
of Geological and Geophysical Surveys Open-File Report 6, scale
1:250,000.
8) Alaska Division of Geological and Geophysical Surveys, 1973,
Aeromagnetic map, Northwest Norton Bay Quadrangle: Alaska Division
of Geological and Geophysical Surveys Open-File Report 7, scale
1:250,000.
Notes:
1) This data set is listed under AOF1-7 series of data, and has been
acquired as a USGS grid format.
2) IGRF removed in original data set.
3) In order to preserve the much higher resolution along the profiles, we have
levelled the final residual magnetic field to the composite or to the merged
grid:
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the merged grid.
*By subtracting from the profile data, the first order trend of the difference
between profile data and data extracted from the composite grid.
Where composite data were missing on the whole length of the profiles, a first
order trend of the profile data was removed in the final composite channel.
Original "Info" file (edited):
Project no. AK07
Name: Seward Peninsula
Flown by: LKB Resources
Number of line miles flown: 15,500
Instrument: Fluxgate magnetometer
Digitized from the original 1:63,360-scale maps.
See Project no. CADY
***********************************************************
Project No: AK08, AK13
Name: East Alaska Range (Healy and Mt. Hayes)
Date Flown: 1971
Altitude: 1000 feet Above Ground
Spacing: 0.75 mile, N-S
Merge Priority:
References:
1) Alaska Division of Geological and Geophysical Surveys, 1973,
Aeromagnetic map, (Eastern) Healy Quadrangle: Alaska Division
of Geological and Geophysical Surveys Open-File Report 9,
5 p., scale 1:250,000.
2) Alaska Division of Geological and Geophysical Surveys, 1973,
Aeromagnetic map, Mt. Hayes Quadrangle: Alaska Division
of Geological and Geophysical Surveys Open-File Report 10,
5 p., scale 1:250,000.
Notes:
1) This data set was digitized from contours. It contains the survey AK13
(Healy Mt. Hayes fill in), as an integral part.
2) IGRF removed in original grid.
3) We have provided two distinct data bases in this case, one with the
originally digitized data ak08.gdb, and one with data extracted from a
regular grid:
As data delivered to us were digitized along contours, the corresponding
profile data base ak08.gdb is not of much practical use. We have produced a
new data base ak08_grid.gdb, by gridding the digitized data at 100 m grid cell
size, tranposing the resulting grid in order to sample in the actual flight
line direction, and then extracting that grid to a new database, every 500 m,
with all relevant channels reincluded. MAG_COMP and MAG_MERGE were both
extracted from their corresponding grids.
Original info file (edited):
Project no.: AK08 and AK13
Name: East Alaska Range and Healy-Mt Hayes Fill-in
Flown by: LKB Resources
Number of line miles: 28,100 (for all quadrangles)
Instrument: Fluxgate magnetometer
Digitized from the original 1:63,360-scale maps
***********************************************************
Project No: AK08A
Name: East Alaska Range (Tanacross)
Date Flown: 1971
Altitude: 1000 feet Above Ground
Spacing: 0.75 mile, N-S
Merge Priority: 4
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Alaska Division of Geological and Geophysical Surveys, 1973,
Aeromagnetic map, Tanacross quadrangle: Alaska Division of Geological
and Geophysical Surveys Open File Report 11, 5 p., scale 1:250,000.
2) Griscom, Andrew, 1976, Aeromagnetic map of the Tanacross
quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field
Investigations Map MF-767-A, 2 sheets, scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 71/01/01 date, and FLTSURF channel for elevation.
3) Processing Notes:
-4963 nT datum shift applied
IGRF 1965
Decorrugation:
BTWR 0.0002
DCOS-Dir 83
DCOS-Deg 0.7
Original "Info" file (edited):
Project no.: AK08
Name: East Alaska Range (Tanacross quad)
Flown by: LKB Resources
Number of line miles: 28,100 (for all quadrangles)
Instrument: Fluxgate magnetometer
Digitized by: Esther Castellanos, 10/90
Map scale: 1:63,360
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Total Field (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
***********************************************************
Project No: AK08B
Name: East Alaska Range (Nabesna)
Date Flown: 1971
Altitude: 1000 feet Above Ground
Spacing: 0.75 mile, N-S
Merge Priority: 4
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Alaska Division of Geological and Geophysical Surveys, 1973,
Aeromagnetic map, Nabesna Quadrangle: Alaska Division of Geological
and Geophysical Surveys Open File Report 13, 5 p., scale 1:250,000.
2) Griscom, Andrew, 1975, Aeromagnetic map of the Nabesna
Quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field
Investigations Map MF-655-H, 2 sheets, scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 71/06/30 date, and FLTSURF channel for elevation.
3) Processing Notes:
-4949 nT datum shift applied
IGRF 1965
Decorrugation:
BTWR 0.00021
DCOS-Dir 82.5
DCOS-Deg 0.7
Original "Info" file (edited):
Survey number: AK08
Name: East Alaska Range (Nabesna quad)
Flown by: LKB Resources
Number of line miles: 28,100 (for all quadrangles)
Instrument: Fluxgate magnetometer
Digitized by: Esther Castellanos, 10/90
Map scale: 1:63,360
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Total Field (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
Datum: Regional magnetic field value at -144W, 62.25N = 56,760 nT.
Regional magnetic field (IGRF) removed. Approximate value
of regional = 5.2 nT/mile, N 57 E.
***********************************************************
Project No: AK09
Name: Goodnews Area
Date Flown: 1971
Altitude: 1000 feet Above Ground
Spacing: 0.75 mile, E-W
Merge Priority: 6
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Griscom, Andrew, 1978, Aeromagnetic interpretation of the Goodnews
and Hagemeister Island quadrangles region, southwestern Alaska: U.S.
Geological Survey Open-File Report 78-9C, scale 1:250,000.
2) Alaska Division of Geological and Geophysical Surveys, 1973,
Aeromagnetic map, Northwest Nushagak Bay quadrangle: Alaska Division
of Geological and Geophysical Surveys Open File Report 17, 5 p., scale
1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 71/06/30 date, and FLTSURF channel for elevation.
3) Processing Notes:
-5033 nT datum shift applied
IGRF 1965
Decorrugation:
BTWR 0.0002
DCOS-Dir 07
DCOS-Deg 0.5
Original "Info" file (edited):
Project no.: AK09
Name: Goodnews (includes Nushagak and Hagemeister Island)
Flown by: LKB Resources
Number of line miles: 12,200
Instrument: Fluxgate magnetometer
Digitized by: Esther Castellanos, 9/96 to 10/96
Map scale: 1:63,360
Datum: Regional Mag field value = 53,351 nT at (-162,59)
Regional field of approx. 7.0 nT/mile, N29E, applied
(approximate IGRF)
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Residual mag (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
***********************************************************
Project No: AK10
Name: Eagle
Date Flown: 1972
Altitude: 1000 feet Above Ground
Spacing: 0.75 mile, N-S
Merge Priority: 5
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Alaska Division of Geological and Geophysical Surveys, 1973,
Aeromagnetic map, Eagle Quadrangle: Alaska Division of Geological and
Geophysical Surveys Open File Report 18, 5 p., scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 72/01/01 date, and FLTSURF channel for elevation.
3) Processing Notes:
-5033 nT datum shift applied
IGRF 1965
Decorrugation:
BTWR 0.000155
DCOS-Dir 83
DCOS-Deg 0.5
Original "Info" file (edited):
Project no.: AK10
Name: Eagle
Company: LKB Resources
Number of line miles: 7900
Instrument: Fluxgate magnetometer
Digitized by: Esther Castellanos, 10/89
Map scale: 1:63,360
Datum: Regional magnetic field 57,122 nT at SW corner of quad (64 N, 144W).
Regional field of approximately 4.5 nT/mile, N 60 E, removed.
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Total Field (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
***********************************************************
Project No: AK11
Name: Talkeetna-Anchorage
Date Flown: 1972
Altitude: 1000 feet Above Ground
Spacing: 0.75 mile, N-S
Merge Priority:
References:
1) Csejtey, Jr., Bela, and Griscom, Andrew, 1978, Preliminary aeromagnetic
interpretative map of the Talkeetna Mountains Quadrangle, Alaska: U.S.
Geological Survey Open-File Report 78-558C, 15p., scale 1:250,000.
2) Alaska Division of Geological and Geophysical Surveys, 1973, Aeromagnetic
map, Talkeetna Quadrangle: Alaska Division of Geological and Geophysical
Surveys Open-File Rept. AOF-19, 5 p., 1 sheet, scale 1:2500,000.
3) Alaska Division of Geological and Geophysical Surveys, 1973, Aeromagnetic
map, Talkeetna Mountains Quadrangle: Alaska Division of Geological and
Geophysical Surveys Open-File Rept. AOF-20, 5 p., 1 sheet, scale
1:2500,000.
4) Alaska Division of Geological and Geophysical Surveys, 1973, Aeromagnetic
map, (northern) Anchorage Quadrangle: Alaska Division of Geological and
Geophysical Surveys Open-File Rept. AOF-21, 5 p., 1 sheet, scale
1:2500,000.
Notes:
1) This data set was digitized from contours.
2) IGRF removed in original grid.
3) We have provided two distinct data bases in this case, one with the
originally digitized data ak11.gdb, and one with data extracted from a
regular grid:
As data delivered to us were digitized along contours, the corresponding
profile data base ak08.gdb is not of much practical use. We have produced a new
data base ak08_grid.gdb, by gridding the digitized data at 500 m grid cell
size, tranposing the resulting grid in order to sample in the actual flight
line direction, and then extracting that grid to a new database,every 500 m,
with all relevant channels reincluded. MAG_COMP and MAG_MERGE were both
extracted from their corresponding grids.
Original info file (edited):
Project no. AK11
Name: Talkeetna-Anchorage
Flown by: LKB Resources
Number of line miles: 18,000 (for all quadrangles)
Instrument: Fluxgate magnetometer
Digitized form original 1:63,360-scale maps
Long
Lat
Digitized Total Field
***********************************************************
Project No: AK12
Name: Big Delta-Fairbanks
Date Flown: 1973
Altitude: 1000 feet Above Ground
Spacing: 0.75 mile, N-S
Merge Priority:
References:
1) Alaska Division of Geological and Geophysical Surveys, 1973, Aeromagnetic
map, Fairbanks Quadrangle: Alaska Division of Geological and Geophysical
Surveys Open-File Report 8, 5 p., 1 sheet, scale 1:250,000.
2) Alaska Division of Geological and Geophysical Surveys, 1973, Aeromagnetic
map, Big Delta Quadrangle: Alaska Division of Geological and Geophysical
Surveys Open-File Report 73, 5 p., 1 sheet, scale 1:250,000.
Notes:
1) This data set was digitized from contours.
2) IGRF removed in original grid.
3) The original grid was microlevelled in order to remove flight line related
noise. The resulting channel is MAG_IGRF.
3) We have provided two distinct data bases in this case, one with the
originally digitized data ak12.gdb, and one with data extracted from a
regular grid:
As data delivered to us were digitized along contours, the corresponding
profile data base ak12.gdb is not of much practical use. We have produced a
new data base ak12_grid.gdb, by gridding the digitized data at 500 m grid cell
size, tranposing the resulting grid in order to sample in the actual flight
line direction, and then extracting that grid to a new database,every 500 m,
with all relevant channels reincluded. MAG_COMP and MAG_MERGE were both
extracted from their corresponding grids, as well as the MAG_IGRF channel
(from the microlevelled grid).
Original "Info" file (edited):
Project no. AK12
Name: big Delta-Fairbanks
Flown by: LKB Resources
Number of line miles: 16,000
Instrument: Fluxgate magnetometer
Digitized from the original 1:63,360-scale maps.
Long
Lat
Digitized Total Field
***********************************************************
Project No: AK14 and AK15
Name: Baird Mountains-Ambler River and Survey Pass Areas
Date Flown: 1973-1974; 1975
Altitude: 1000 feet Above Ground
Spacing: 1.0 mile, N-S; 0.75-1.0 mile, N-S
Merge Priority: 13
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Alaska Division of Geological and Geophysical Surveys, 1975,
Aeromagnetic map, Western Ambler River Quadrangle: Alaska Division of
Geological and Geophysical Surveys Open File Report 76, 5 p., scale
1:250,000.
2) Alaska Division of Geological and Geophysical Surveys, 1975,
Aeromagnetic map, Eastern Baird Mountains Quadrangle: Alaska Division
of Geological and Geophysical Surveys Open File Report 77, 5 p., scale
1:250,000.
4) Alaska Division of Geological and Geophysical Surveys, 1975,
Aeromagnetic map, northeast Selawik Quadrangle, Alaska Division
of Geological and Geophysical Surveys Open-File Report 78, 5 P.,
1 sheet, scale 1:250,000.
3) Decker, John, and Dillion, J.T., 1982, Aeromagnetic map, Survey
Pass quadrangle: Alaska Division of Geological and Geophysical Surveys
Open File Report 175, scale 1:250,000.
5) Decker, John and Dillon, J.T., comp., 1982 Aeromagnetic map of the
northern portion of the Shungnak Quadrangle: Alaska Division of
Geological and Geophysical Surveys Open-File Report 177, scale
1:250,000.
6) Decker, John and Dillon, J.T., comp., 1982 Aeromagnetic map of the
northern half of the Hughes Quadrangle: Alaska Division of Geological
and Geophysical Surveys Open-File Report 178, scale 1:250,000.
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 74/01/01 date, and FLTSURF channel for elevation.
3) Processing Notes:
Combined original surveys AK14 & AK15
+18 nT datum shift applied
IGRF 1965
Tilt removed: 0, 0.0000894, -0.000306
Decorrugation: None
Original "Info" file (edited):
Project no.: AK14 and AK15
Name: Baird Mtns - Ambler River & Survey Pass Area
Company: GeoMetrics
Number of line miles: 19,900
Instrument: GeoMetrics G-803 proton magnetometer
Digitized by: Esther Castellanos, 9/86
New Shungnak D3 quad added by Saltus 10/96
Map scales: 1:63,360
Datum: 56188.10 nT at 66.75N and 161W (SW corner of survey)
A planar regional trend was removed from each 1:63,360 quad using
the 1965 IGRF updated to the year of the survey (1973, 1974, and 1975).
In the SW corner of the map this regional trend was
3.85 nT/mile north and 2.26 nT/mile east.
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Total Field (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
***********************************************************
Project No: AK16
Name: South NPR 1977
Date Flown: 9/23/77-9/26/77
Altitude: 800 feet Above Ground
Spacing: 6 to 10 miles, N-S
Merge Priority: 99
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Gibson, H. A., and Tailleru, I. L., 1980, Map showing relation between
aeromagnetic data and geology, southern National Petroleum Reserve in
Alaska: U.S. Geological Survey Open-File Report 80-516, 3 sheets scale
1:250,000 and 1:63,360
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 77/09/25 date, and FLTSURF channel for elevation.
3) Processing Notes:
-29 nT datum shift applied
Tilt removed: 1933.2699, -0.001334086,-0.00153798
Filters applied: 0.1 km non-linear, 1.2 km low-pass, Hanning 2x
Decorrugation: None
Original "Info" file(edited):
Project no.: AK16
Name: South NPR 1977
Flown by: Husky Oil (GSI)
Number of line miles: 1200
Instrument: unknown
Datum unknown
Digital data source: National Geophysical Data Center, Boulder Colorado
Fortran data format:
(i5,i4,i6,i7,i6,i4,a4,a4,i2,9f9.2)
1 2 3 4 5 6 7 8 9,10-19
Where
1 = tape (?)
2 = record id
3 = latitude (in degrees with 4 decimal places)
4 = longitude (in degrees with 4 decimal places)
5 = residual magnetics (in nT, datum unknown)
6 = terrain clearance (in ft)
7 = empty
8 = empty
9 = data quality (?)
10 - 19 = radiometric channels (if needed contact NGDC for further info)
(Info from Bob Morin, entered by Rick Saltus 12/26/96)
***********************************************************
Project No: AK17
Name: Wiseman-Bettles
Date Flown: 03/1978
Altitude: 1000 feet Above Ground
Spacing: 0.75 mile, N-S
Merge Priority: 12
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Decker, John, and Dillion, J.T., 1982, Aeromagnetic map, Survey
Pass quadrangle: Alaska Division of Geological and Geophysical Surveys
Open File Report 175, scale 1:250,000.
2) Decker, John, and Dillion, J.T., 1982, Aeromagnetic map, Wiseman
quadrangle: Alaska Division of Geological and Geophysical Surveys Open
File Report 176, scale 1:250,000. (This map is a composite of DGGS and
USGS data)
3) Decker, John, and Dillion, J.T., 1982, Aeromagnetic map, Northern
Shungnak quadrangle: Alaska Division of Geological and Geophysical
Surveys Open File Report 177, scale 1:250,000.
4) Decker, John, and Dillion, J.T., 1982, Aeromagnetic map, Northern
Hughes quadrangle: Alaska Division of Geological and Geophysical
Surveys Open File Report 178, scale 1:250,000.
5) Decker, John, and Dillion, J.T., 1982, Aeromagnetic map, Bettles
quadrangle: Alaska Division of Geological and Geophysical Surveys Open
File Report 179, scale 1:250,000. (This map is a composite of DGGS and
USGS data)
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 78/03/01 date, and a constant of 305.0 m for elevation.
3) Many "dropouts" (suspicious extreme values) in the original MAG_RAW channel
were changed to dummys for processing.
4) No datum shift applied
Decorrugation:
BTWR 0.0002
DCOS-Dir 90.925
DCOS-Deg 0.75
Original "Info" file (edited):
Project no. AK17
Name: Wiseman-Bettles
Flown by: GeoMetrics
Number of line miles: 11,200
Instrument: GeoMetrics proton magnetometer
National Geophysical Data Center (NGDC) data header:
1DNR-0001TG04-0260-922 F R 850000USGS - Flown by GeoMetrics, Inc. 01
USA Aircraft ??? 3PLANE Dep. of Natural Resources, AK 02
West Central Brooks Range, Alaska 03
780300 780300 04
N-S: 1.2 Kilometers 05
305 Meters AG IGRF-75 427531 06
LINE-NUMBER(A6),DATE-FLOWN-MMMMYY(A6),UTM-NORTHING-M(F12.2),UTM-
EASTING-M 07
(F12.2),FIDUCIAL-NUMBER(F12.2),TOTAL-MAGNETIC-FIELD-nT(F12.2),RESIDUAL- 08
MAGNETIC-FIELD-nT(F12.2),LATITUDE(F12.6),LONGITUDE(F12.6)| 09
10
11
1 7615,9999, , , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +69+65-157-15016
W00663, 00677 17
Central Meridian Used = 153: False Easting = 500: False Northing = -7000 18
The above mentioned UTM projection parameters were used to process LAT/LON 19
coordinates using the Clark 1866 spheroid. These projection figures are 20
ASSUMPTIONS used after every effort was made to obtain specifics relating to 21
the projection and coordinate system. PLEASE NOTE: The original UTM 22
coordinates are still present in the *.inp data set. 23
Open File Report: 24
***********************************************************
Project No: AK21, AK22
Name: Prudhoe Bay Region and Arctic Natl Wildlife Refuge
Date Flown: 1981
Altitude: 300 feet Above Ground
Spacing: 1-3 miiles, N-S (AK21) and E-W (AK22)
Merge Priority: 24
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Donovan, T.J., and others, 1984, Low-altitude aeromagnetic
reconnaissance for petroleum in the Arctic National Wildlife Refuge,
Alaska: Geophysics, v. 49, no. 8, p. 1338-1353.
Notes:
1) Base station is NOT available for this survey.
2) Combined AK21 & AK 22, processed as one survey,
3) DGRF used 81/06/15 date, and FLTSURF channel for elevation.
4) Processing Notes:
+1 nT datum shift applied
Decorrugation: AK21
BTWR 0.0000777
DCOS-Dir 85
DCOS-Deg 0.5
Decorrugation: AK22
BTWR 0.0000777
DCOS-Dir 355
DCOS-Deg 0.5
Original "Info" file (edited):
Project no.: AK21 and AK22
Name: Prudhoe Bay Region and Arctic Natl Wildlife Refuge
Flown by: T.J. Donovan (USGS)
Number of line miles: 1745
Instrument: Proton magnetometer
Digital data source: NGDC file 0260-926
Ascii data fields:
1. Flightline number (i4) [a4]
2. Longitude [f10.4]
3. Latitude [f9.4]
4. Tail mag (total field, nT) [f9.2]
5. Left wing mag (total field, nT) [f9.2]
6. Right wing mag (total field, nT) [f9.2]
7. Radar altimeter (ft) [f5.0]
8. Julian date (day of year) [f5.0]
9. Leveled mag (arbitrary datum, nT) [f8.2]
Fortran format:
(a4,f10.4,f9.4,3f9.2,f5.0,f5.0,f8.2)
Data fields 1-8 are from NGDC data file.
Data field 9 (Leveled mag) is based on line-leveling of field 4 (tail mag)
after application of DGRF for the time of the survey. The line-leveling
was done by comparison with regional data from two proprietary surveys
for this area. The best-fitting DC offset was applied to each survey
line to match it to the average levels of the proprietary surveys.
This procedure leaves some obvious flightline noise that will require
filtering for production of a smooth grid. The large-amplitude basement
anomaly centered at about 70 N and 145 W should be smooth. It can be
used as a guideline for filtering.
[Line-leveling done by Rick Saltus, USGS, 16 October 1996]
National Geophysical Data Center (NGDC) data header:
1USGSANWRTG04-0260-926 F 911011USGS - EROS Data Center 01
USA U8G Beech-E-50 3PLANE USGS Branch of Geophysics 02
Arctic National Wildlife Refuge, Alaska ~2,600 Traverse Miles 03
810711 810721 04
N-S & E-W: 1.0 Miles Proton Precession 05
300 Feet AG 67 m/s 1StingerIGRF-80 75000 0.1 nT06
JULIAN-DATE(F4.0),HOURS(F3.0),MINUTES(F3.0),SECONDS(F3.0),TAIL-STINGER- 07
MAGNETOMETER(F10.3),LEFT-WING-TIP-MAGNETOMETER(F10.3),RIGHT-WING-TIP-
08
MEGNETOMETER(F10.3),RADAR-ALTIMETER-HUNDREDS-FEET(F5.2),LINE-
NUMBER(F3.0), 09
LATITUDE(F9.4),LONGITUDE(F9.4)| 10
11
2 7614,7714,9999, , , , , , , , , , , , ,12
, , , , , , , , , , , , , , , 13
, , , , , , , , , , , , , , , 14
, , , , , , , , , , , , , , , 15
, , , , , , , , , +71+69-148-14216
W05139 17
Publications: Open File Report - 18
19
***********************************************************
Project No: AK23
Name: Eastern Copper River
Date Flown: 1971
Altitude: 500 feet Above Ground
Spacing: 0.5 mile, N-S
Merge Priority:
References:
1) Wescott, E.M., and Turner, D.L., 1985, Geothermal energy resource investi-
gations in the eastern Copper River Basin, Alaska, University of Alaska
Geophysical Institute Report UAG R-302, 158 p., 8 plates, scale 1:630,360.
Notes:
1) This data set was digitized from contours.
2) IGRF removed in original grid.
3) We have provided two distinct data bases in this case, one with the
originally digitized data ak08.gdb, and one with data extracted from a
regular grid:
As data delivered to us were digitized along contours, the corresponding
profile data base ak23.gdb is not of much practical use. We have produced a new
data base ak23_grid.gdb, by gridding the digitized data at 100 m grid cell
size, tranposing the resulting grid in order to sample in the actual flight
line direction, and then extracting that grid to a new database, every 500 m,
with all relevant channels reincluded. MAG_COMP and MAG_MERGE were both
extracted from their corresponding grids.
Original "Info" file 9 (edited):
Project no. AK23
Name: Eastern Copper River
Flown by: Ertec
Number of line miles: 660
Instrument: Unknown
Long
Lat
Digitized Total Field
***********************************************************
Project No: AK24 and AK25
Name: Phillips compilation 1/2 km grid
Date Flown: 1992 merge
Altitude: 1000 feet above ground*
Spacing: 500 meter grid
Merge Priority: 10
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
Notes:
1) Base station is NOT available for this survey.
2) * Original elevation was listed as 1400' Barometric; topography indicates this
could not be the case, later information received indicates it was actually
1000' draped.
3) The Alaska Merged Grid (AMG) was downward continued based on a 1400' Barometric
elevation, no adjustment has been made.
4) MAG_RAW field is blank, as this data was received already DGRFed.
5) MAG_COMP & MAG_MERGE fields are based on MAG_DGRF differences.
6) Processing Notes:
+78 nT datum shift applied
Decorrugation:
BTWR 0.000125
DCOS-Dir \8.5
DCOS-Deg 0.5
Original "Info" file (edited):
Project No. AK24 and AK25
Name: Bethel Õ88 and Bethel Õ89
Flown by: J. Phillips (USGS)
Number of line miles: unknown
Instrument: Unknown
Grid: Bethel/Russian Mission mag grid
Author: Jeff Phillips, USGS, Denver
Datum: DGRF removed
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Total Field (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
Notes:
This grid has been draped to 1000' above terrain (not reduced to the pole).
The XYZ records are extracted from the original 0.5 km projected grid
(Transverse Mercator, baslat=0, cm=-160.5) and unprojected to
lat/lon coordinates.
This grid contains data from a field survey by Jeff Phillips during
work on the AMRAP project for the Bethel Quad (year 1988-1989) as well as
data from later State of Alaska contracted surveys.
***********************************************************
Project No: AK26, AK27, and AK28
Name: Nome Mining District (Dighem Survey)
Date Flown: 08/1993
Altitude: 130 feet Above Ground
Spacing: 0.125 and 0.25 mile, N-S and E-W
Merge Priority:
References:
1) Alaska Division of Geological and Geophysical Surveys, 1994, Total field
magnetic and electromagnetic anomalies of the Nome mining district: Alaska
Division of Geological and Geophysical Surveys, Report of Investigations
94-1, scale 1:63,360.
2) Alaska Division of Geological and Geophysical Surveys,Dighem, and WGM,
1994, CD-ROM digital archive files of 1993 survey data for Nome, Circle,
Nyac, and Valdez Creek mining districts: Alaska Division of Geological and
Geophysical Surveys Public Data File 94-15.
Notes:
1) This is a Dighem high resolution HEM survey
2) The height channel (Radar altimeter) was originally in feet, and was
recalculated in meters.
3) The MAG_RAW channel is actually the MAG processed by the original contractor
(tie line levelling, diurnal correction etc.). No MAG_IGRF channel
available.
4) None of the DIGHEM surveys was used in the making of the composite and merge
grids, so that the USE_FLAG channel was set to 0.
5) Since the survey was flown at 130' nominal height, and the merged grid was
merged at 1000 feet, profile data for the mag_merge channel were accordingly
upward continued before adjusting them to the merged grid.
6) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid:
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the corresponding grid.
Original "Info" file (edited):
Project no. AK26, AK27, and AK28
Name: Mt. Distin, Nome North, and Nome Mining District
Flown by: Dighem
Number of line miles: 3260
Instrument: Scintrex CS2 cesium magnetometer
Data were recovered from the Dighem database of combined helicopter EM
and magnetic surveys. The following channels were recovered:
X (UTM)
Y (UTM)
Fiducial
RALT
BALT
MAG
***********************************************************
Project No: AK29
Name: Circle (Dighem Survey)
Date Flown: 08/1993
Altitude: 130 feet Above Ground
Spacing: 0.25 mile, N-S
Merge Priority:
References:
1) Alaska Division of Geological and Geophysical Surveys, 1994, Total field
magnetic and electromagnetic anomalies of the Circle mining district:
Alaska Division of Geological and Geophysical Surveys, Report of
Investigations 94-2, scale 1:63,360.
2) Alaska Division of Geological and Geophysical Surveys,Dighem, and WGM,
1994, CD-ROM digital archive files of 1993 survey data for Nome, Circle,
Nyac, and Valdez Creek mining districts: Alaska Division of Geological and
Geophysical Surveys Public Data File 94-15.
Notes:
1) This is a Dighem high resolution HEM survey
2) The height channel (Radar altimeter) was originally in feet, and was
recalculated in meters.
3) MAG_RAW is the MAG channel recovered from the DIGHEM database.
4) None of the DIGHEM surveys was used in the making of the composite and merge
grids, so that th USE_FLAG channel was set to 0.
5) Since the survey was flown at 130' nominal height, and the merged grid was
merged at 1000 feet, profile data for the mag_merge channel were accordingly
upward continued before adjusting them to the merged grid.
6) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid:
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the corresponding grid.
Original "Info" file (edited):
Project no. AK29
Name: Circle Mining District
Flown by: Dighem
Number of line miles: 1564
Instrument: Scintrex CS2 cesium magnetometer
Data were recovered from the Dighem database of combined helicopter EM
and magnetic surveys. The following channels were recovered:
X (UTM)
Y (UTM)
Fiducial
RALT
BALT
MAG
***********************************************************
Project No: AK30
Name: Nyac Mining District (Dighem Survey)
Date Flown: 08/1993
Altitude: 130 feet Above Ground
Spacing: 0.25 mile, N50W
Merge Priority:
References:
1) Alaska Division of Geological and Geophysical Surveys, 1994, Total field
magnetic and electromagnetic anomalies of the Nyac mining district: Alaska
Division of Geological and Geophysical Surveys, Report of Investigation
94-3, scale 1:63,360.
2) Alaska Division of Geological and Geophysical Surveys,Dighem, and WGM,
1994, CD-ROM digital archive files of 1993 survey data for Nome, Circle,
Nyac, and Valdez Creek mining districts: Alaska Division of Geological and
Geophysical Surveys Public Data File 94-15.
Notes:
1) This is a Dighem high resolution HEM survey
2) The height channel (Radar altimeter) was originally in feet, and was
recalculated in meters.
3) Since the survey was flown at 130' nominal height, and the merged grid was
merged at 1000 feet, profile data for the MAG_MERGE channel were accordingly
upward continued before adjusting them to the merged grid.
4) The MAG_RAW channel is actually the MAG processed by the original contractor
(tie line levelling, diurnal correction etc.). No MAG_IGRF channel
available.
5) None of the DIGHEM surveys was used in the making of the composite and merge
grids, so that th USE_FLAG channel was set to 0.
6) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid:
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the corresponding grid.
Original "Info" file (edited):
Project no. AK30
Name: Nyac Mining District
Flown by: Dighem
Number of line miles: 850
Instrument: Scintrex CS2 cesium magnetometer
Data were recovered from the Dighem database of combined helicopter EM
and magnetic surveys. The following channels were recovered:
X (UTM)
Y (UTM)
Fiducial
RALT
BALT
MAG
***********************************************************
Project No: AK31
Name: Valdez Creek (Dighem Survey)
Date Flown: 08/93
Altitude: 130 feet Above Ground
Spacing: 0.25 mile, N18W
Merge Priority:
References:
1) Alaska Division of Geological and Geophysical Surveys, 1994, Total field
magnetic and electromagnetic anomalies of the Valdez Creek mining district:
Alaska Division of Geological and Geophysical Surveys, Report of
Investigation 94-4, scale 1:63,360.
2) Alaska Division of Geological and Geophysical Surveys,Dighem, and WGM,
1994, CD-ROM digital archive files of 1993 survey data for Nome, Circle,
Nyac, and Valdez Creek mining districts: Alaska Division of Geological and
Geophysical Surveys Public Data File 94-15.
Notes:
1) This is a Dighem high resolution HEM survey
2) The height channel (Radar altimeter) was originally in feet, and was
recalculated in meters.
3) The MAG_RAW channel is actually the MAG processed by the original contractor
(tie line levelling, diurnal correction etc.)
4) None of the DIGHEM surveys was used in the making of the composite and merge
grids, so that th USE_FLAG channel was set to 0.
5) Since the survey was flown at 130' nominal height, and the merged grid was
merged at 1000 feet, profile data for the mag_merge channel were accordingly
upward continued before adjusting them to the merged grid.
6) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to the
merged grid:
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the corresponding grid.
Original "Info" file (edited):
Project no. AK31
Name: Valdez Creek
Flown by: Dighem
Number of line miles: 370
Instrument:
Data were recovered from the Dighem database of combined helicopter EM
and magnetic surveys. The following channels were recovered:
X (UTM)
Y (UTM)
Fiducial
RALT
BALT
MAG
***********************************************************
Project No: AK32
Name: SE Bethel Basin
Date Flown: 08/1994
Altitude: 300 feet Above Ground (Flying)
Spacing: 0.5 mile, NW(125)-SE(305)
Merge Priority:
References:
1) Alaska Division of Geological and Geophysical Surveys, and Geonex Aero
Service, 1995, Total field magnetics of the southeastern Bethel Basin,
Alaska: AKDGGS Rept. Inv. 95-1, 2 sheets, scale 1:125,000.
2) Alaska Division of Geological and Geophysical Surveys, and Geonex Aero
Service, 1995, Digital gridded data of total field magnetics of the
southeastern Bethel Basin, Alaska: AKDGGS Public-Data File 95-1,
1 diskette
Notes:
1) This data set was recieved in a digital grid format.
2) IGRF removed in original grid.
3) This grid was extracted to bethel.gdb and MAG_COMP and MAG_MERGE were both
extracted from their corresponding grids.
Original "Info" file (edited):
Project no. AK32
Name: SE Bethel Basin
Flown by: Geonex (Aero Service)
Number of line miles: 1000
Instrument: unknown
***********************************************************
Project No: AK33, AK34
Name: Fairbanks East and West (Dighem Surveys)
Date Flown: 1994
Altitude: 130 feet Above Ground
Spacing: 0.25 mile, NW-SE and N-S
Merge Priority:
References:
1) Alaska Division of Geological and Geophysical Surveys, Dighem, and W.G.M.,
1995, Total field magnetics & electromagnetic anomalies of the Fairbanks
mining district: Alaska Division of Geological and Geophysical Surveys
Report of Investigation 95-4, 2 sheets, scale 1:63,360.
2) Alaska Division of Geological and Geophysical Surveys, 1995, CD-ROM digital
archive files of 1994 survey data for Fairbanks and Richardson mining
districts: Alaska Division of Geological and Geophysical Surveys Public
Data File 95-11.
Notes:
1) This is a Dighem high resolution HEM survey.
2) The height channel (Radar altimeter) was originally in feet, and was
recalculated in meters.
3) The MAG_RAW channel is actually the MAG processed by the original contractor
(tie line levelling, diurnal correction etc.)
4) None of the DIGHEM surveys was used in the making of the composite and merge
grids, so that th USE_FLAG channel was set to 0.
5) The MAG_IGRF channel is actually the MAG_RAW channel with a second order
trend removed from it instead of the IGRF, by the original contractor, at
the clients request.
6) Since the survey was flown at 130' nominal height, and the merged grid was
merged at 1000 feet, profile data for the mag_merge channel were accordingly
upward continued before adjusting them to the merged grid.
7) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid:
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the corresponding grid.
Original "Info" file (edited):
Project no. AK33 and AK34
Name: Fairbanks EM West and Fairbanks EM East
Flown by: Dighem
Number of line miles: 2950
Instrument: Scintrex CS2 cesium magnetometer
Data were recovered from the Dighem database of combined helicopter EM
and magnetic surveys. The following channels were recovered:
X (UTM)
Y (UTM)
Fiducial
RALT
BALT
MAG
***********************************************************
Project No: AK37
Name: Rampart-Manley (Dighem Survey)
Date Flown: 10/1995
Altitude: 130 feet Above Ground
Spacing: 0.25 mile, N-S
Merge Priority:
References:
1) Alaska Division of Geological and Geophysical Surveys, Dighem, and W.G.M.,
1996, Total field magnetics and electromagnetic anomalies of the Rampart-
Manley mining district, Alaska Division of Geological and Geophysical
Surveys Report of Investigation 96-1, 2 sheets, scale 1:63,360.
2) Alaska Division of Geological and Geophysical Surveys, Dighem, and WGM,
1996, CD-ROM digital archive files of 1994 survey data for Rampart-Manley
mining district,Alaska: Alaska Division of Geological and Geophysical
Surveys, Public Data File 96-5.
Notes:
1) This is a Dighem high resolution HEM survey.
2) The height channel (Radar altimeter) was originally in feet, and was
recalculated in meters.
3) The MAG_RAW channel is actually the MAG processed by the original contractor
(tie line levelling, diurnal correction etc.)
4) None of the DIGHEM surveys was used in the making of the composite and merge
grids, so that the USE_FLAG channel was set to 0.
5) Since the survey was flown at 130' nominal height, and the merged grid was
merged at 1000 feet, profile data for the mag_merge channel were accordingly
upward continued before adjusting them to the merged grid.
6) In order to preserve the much higher resolution along the measured profiles,
we have levelled the final residual magnetic field to the composite or to
the merged grid:
*By subtracting from the profile data, a long wave lengh component (i.e. low
pass filtered) of the difference between profile data and data extracted from
the corresponding grid.
Original "Info" file (edited):
Project no.: AK37
Name: Rampart-Manley Mining District
Flown by: Dighem
Number of line miles: 3000
Instrument: Scintrex CS2 cesium magnetometer
Data were recovered from the Dighem database of combined helicopter EM
and magnetic surveys. The following channels were recovered:
X (UTM)
Y (UTM)
Fiducial
RALT
BALT
MAG
***********************************************************
Project No: CADY
Name: Cady compilation 250 meter grid
Date Flown: 1995 merge
Altitude: 1000 feet Above Ground
Spacing: 250 meter grid
Merge Priority: 11
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Cady, J. W., and Hummel, C.L., 1976, Magnetic studies of selected
geologic and aeromagnetic features in southwest Seward Peninsula, west-
central Alaska: U.S. Geological Survey Open-File Report 76-425, scale
1:125,000.
Notes:
1) Base station is NOT available for this survey.
2) There is no MAG_DGRF field, as this is a compilation of several surveys.
3) MAG_COMP & MAG_MERGE fields are based on RAW_MAG differences, not
MAG_DGRF.
4) Processing Notes:
-5089 nT datum shift applied
Decorrugation: None
Original "Info" file (edited):
Project no.: Cady
Name: Seward Peninsula
Grid: Seward Peninsula Composite Mag
This grid combines data from surveys 3005A, 3005D, 3005F, AK07, and 6008.
Author: John Cady, 1995
Datum: IGRF removed
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Total Field (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
Notes:
This composite grid was prepared under contract to the State of Alaska,
Division of Geological and Geophysical Surveys. A paper map is available
from the State of Alaska (Laurel Burns, coauthor).
***********************************************************
Project No: COOK (Project No. 291)
Name: Cook Inlet
Date Flown: 1957,1958
Altitude: 2500 ft Barometric
Spacing: Various, possible 2 mi spacing, E-W
Merge Priority: 14
"Merge Priority" was assigned to help decide which survey to use in areas
of overlap. 1 is the best quality and 99 the worst.
References:
1) Aeromagnetic Survey, Total Intensity Contours, Aero Service
Corporation, 1957 - 1958, Contour Interval 5 - 10 gammas. Paper map
(scale approx 1:193,000) obtained by George Plafker from Marathon
Oil Co., Permission to use obtained by Robert Morin, from Steve
Trudell 7/15/96.
2) Grantz, Arthur, Zietz, Isidore, and Andreasen, G.E., 1963, An
aeromagnetic reconnaissance of the Cook Inlet area, Alaska: U.S.
Geological Survey Professional Paper 316-G, 17 p., 5 plates, scale
1:500,000. (Shows aeromagnetic profiles at 1-10 mile spacing).
Notes:
1) Base station is NOT available for this survey.
2) DGRF used 58/01/01 date, and FLTSURF channel for elevation.
3) All values < 100 meters in the HEIGHT channel were set to 100 meters.
4) Processing Notes:
-2947 nT datum shift applied
Removed 3rd order trend surface.
Decorrugation: None
Original "Info" file (edited):
Project no.: COOK (contains parts or all of Project No. 172 and 291)
Name: Cook Inlet (compilation map)
Company: USGS and Aero Service
Approximate number of line miles: 4000
Instrument: An/ASQ-3A fluxgate magnetometer and unknown
Digitized by: DIGIMAP (Esther Castellanos, January 1997)
Map scale: approx. 1:193,000
Datum: arbitrary datum
Data format: Ascii format, XYZ records
Longitude (degrees), Latitude (degrees), Total Field (nT)
written with FORTRAN format: (f10.5,x,f10.5,x,f8.1)
Reference: Paper map (scale approx 1:193,000) obtained by George Plafker
from Marathon Oil Co. Permission to use obtained by
Robert Morin from Steve Trudell 7/15/96. Map is annotated
as follows: "Aeromagnetic Survey, Total Intensity Contours,
Aero Service Corporation, 1957 - 1958, Contour Interval
5 - 10 gammas."
**********************************************************
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