Preliminary integrated geologic map databases for the United States: Digital data for the reconnaissance geologic map for the Yukon Flats region, east central Alaska

Frequently-anticipated questions:

• What does this data set describe?
  1. How should this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. Where did the data come from?
  2. What changes have been made?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

Title:

Preliminary integrated geologic map databases for the United States: Digital data for the reconnaissance geologic map for the Yukon Flats region, east central Alaska

Abstract:

The Yukon Flats basin is an areally extensive forested lowland that contains numerous lakes, streams, and marsh areas bordered by densely vegetated low rolling hills in east central Alaska. The 1:500,000-scale generalized geologic map of the Yukon Flats basin and its borderlands is intended to show major geologic features that surround the basin. Geologic (rock) units are generalized to highlight significant structural boundaries and relationships in order to make the general geologic setting of the basin more clearly evident and the subsurface basin geology more easily inferred. The map was compiled largely from existing geologic maps, most based on field data collected between 1948 and 1974. However, mapping in the Livengood, Circle, and parts of the Bettles and Wiseman quadrangles was done in the late 1970's and 1980's. Data from the Tanana quadrangle was collected as recently as 2003.

This data set is a portion of a statewide geology database, which is being compiled by the U.S. Geological Survey's National Survey and Analysis (NSA) project, whose goal is to compile geologic, geochemical, geophysical, and other data.

1. How should this data set be cited?

   Labay, K.A., Crews, Jesse, Wilson, F.H., Shew, Nora, and Hults, C.K., 2006, Preliminary integrated geologic map databases for the United States: Digital data for the reconnaissance geologic map for the Yukon Flats region, east central Alaska: U.S. Geological Survey Open-File Report OFR 2006-1304.

   Online Links:

   • <http://pubs.usgs.gov/of/2006/1304/>

   This is part of the following larger work.

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -153.0

   East_Bounding_Coordinate: -141.0

   North_Bounding_Coordinate: 68.0

   South_Bounding_Coordinate: 65.0

3. What does it look like?

4. Does the data set describe conditions during a particular time period?

   Calendar_Date: 2006

   Currentness_Reference: publication date

5. What is the general form of this data set?

   Geospatial_Data_Presentation_Form: vector digital data

6. How does the data set represent geographic features?
   1. How are geographic features stored in the data set?

      This is a Vector data set.

   2. What coordinate system is used to represent geographic features?

      Grid_Coordinate_System_Name: Universal Transverse Mercator

      Universal_Transverse_Mercator:

      UTM_Zone_Number: 5

      Transverse_Mercator:

      Scale_Factor_at_Central_Meridian: 0.9996

      Longitude_of_Central_Meridian: -153.0

      Latitude_of_Projection_Origin: 0.0

      False_Easting: 500000

      False_Northing: 0

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000256
      Ordinates (y-coordinates) are specified to the nearest 0.000256
      Planar coordinates are specified in meters

      The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.4.
      The flattening of the ellipsoid used is 1/294.9787.
      

7. How does the data set describe geographic features?

   polygons

   Characteristics of the polygon features in the geology coverages are coded in the polygon attribute table. The table <cov>.pat includes the following items: CLASS, NSACLASS, NSAMOD, QCLASS (not used), SOURCE, LABEL, MIN_AGE, and MAX_AGE. (Source: this data set)

   CLASS

   CLASS is a positive integer value (4 5 B) item in the polygon attribute table. Values range discontinuously from 0 to 4040. CLASS is a numeric code for the geologic unit from Till and others, in prep. Each CLASS matches with a geologic unit label in LABEL and has a minimum (MIN_AGE) and maximum (MAX_AGE) range, given in million of years (my). Each map unit has been assigned an NSACLASS value (4 5 B). NSACLASS is a numeric code used for compilation geologic mapping for the state of Alaska. This data set represents a generalized map, thus it is possible that a geologic unit is made of multiple NSACLASS values. NOTE: Because of the limitations of common GIS fonts, the letters "C", "pC", "Mz", "P", "Pz", "Tr" are substituted for the standard symbols for "Cambrian", "Precambrian", "Mesozoic", "Proterozoic", "Paleozoic", and "Triassic." The letters "C" (Carboniferous and Cambrian) and "P" (Permian and Proterozoic) have multiple age designations, so the user should refer to the geologic unit descriptions for the correct geologic age. (Source: this data set)

   Value	Definition
   4000	Cg - Granite (Carboniferous); NSACLASS = 7050
   4001	CPt - Sedimentary rocks of the Tindir Group (Cambrian? and Proterozoic); NSACLASS = 7990
   4002	DCpu - Older strata of the Porcupine River sequence of Brosge and Reiser (1969), undivided (Devonian to Cambrian); NSACLASS = 6970
   4003	DZs - Metamorphosed sedimentary rocks (Devonian to Proterozoic); NSACLASS = 5560
   4004	DSc - Metamorphosed sedimentary rocks (Devonian and Silurian); NSACLASS = 6990
   4005	JDat - Angayucham-Tozitna terrane, undivided (Early Jurassic to Devonian); NSACLASS = 5133
   4006	JMpu - Younger strata of the Porcupine River sequence of Brosge and Reiser (1069), undivided (Jurassic to Mississippian); NSACLASS = 3280
   4007	JMsu - Strangle Woman Creek sequence of Brosge and Reiser (1969), undivided (Jurassic to Mississippian); NSACLASS = 3270
   4009	KDe - Sedimentary rocks of the Endicott Mountains allochthon of Moore and others (1994) (Cretaceous to Devonian); NSACLASS = 6300
   4010	Kg - Granitic rocks (Cretaceous); NSACLASS = 2492
   4011	KJg - Glenn Shale, upper part (Lower Cretaceous and Jurassic?); NSACLASS = 2861
   4012	KJmu - Sedimentary rocks of the Manley basin, undivided (Cretaceous and Jurassic); NSACLASS = 4730
   4013	Kku - Sedimentary rocks of the Kandik basin, undivided (Cretaceous); NSACLASS = 2122
   4014	Kkyu - Sedimentary rocks of the Yukon-Koyukuk basin, undivided (Cretaceous); NSACLASS = 2030
   4015	Mbu - Rocks of Brooks Range sequence of Brosge and Reiser (2000), undivided (Mississippian); NSACLASS = 6328
   4016	Mzmv - Fine-grained sedimentary rocks and tuff (Mesozoic?); NSACLASS = 2860
   4017	KJu - Sedimentary rocks, undifferentiated (Cretaceous? and Jurassic?); NSACLASS = 2810
   4018	PCta - Sedimentary rocks of the Tatonduk area (Permian to Cambrian); NSACLASS = 5036
   4019	MzPza - Low-grade metamorphic rocks (Mesozoic? and(or) Paleozoic?); NSACLASS = 5209
   4020	PzpCm - Metamorphic rocks (Paleozoic? and(or) Precambrian?); NSACLASS = 8852
   4021	PzpCb - Metasedimentary and metaigneous rocks of the southern Brooks Range and Ruby geanticline (Paleozoic and(or) Precambrian); NSACLASS = 9325
   4022	PzpCh - Metasedimentary and metaigneous rocks of the Hammond terrane (Paleozoic and(or) Precambrian); NSACLASS = 8850
   4023	PzZl - Sedimentary and igneous rocks corresponding to the Livengood area sequence of Weber and others (1992) (Paleozoic to Proterozoic); NSACLASS = 8440
   4024	PzZs - Sedimentary and igneous rocks corresponding to older parts of the Schwatka-Rampart area sequence of Weber and others (1992) (Paleozoic to Proterozoic); NSACLASS = 8442
   4025	PzZw - Sedimentary and igneous rocks corresponding to the older parts of the Fairbanks-White Mountains area sequence of Weber and others (1992) (Paleozoic to Proterozoic); NSACLASS = 8441
   4026	PzpCy - Metamorphic rocks of the Yukon-Tanana Upland, undivided (Paleozoic to Precambrian); NSACLASS = 8630
   4027	Pzqs - Sedimentary and igneous rocks (Paleozoic); NSACLASS = 5965
   4028	Pzum - Sedimentary and igneous rocks corresponding to older parts of the Schwatka-Rampart area sequence of Weber and others (1992) (Paleozoic to Proterozoic); NSACLASS = 5470
   4029	Pzvu - Sedimentary rocks of the Venetie terrane of Silberling and others (1994), undivided (Paleozoic); NSACLASS = 5335
   4030	Tb - Basalt flows and rare cinder cones (Tertiary); NSACLASS = 1056
   4031	Qu - Unconsolidated and poorly consolidated sediments, undivided (Quaternary); NSACLASS = 100
   4032	Tg - Granitic rocks (Tertiary); NSACLASS = 1320
   4033	TKs - Sedimentary rocks (Tertiary and Cretaceous); NSACLASS = 1510
   4034	TrPgt - Glenn Shale, lower part, and Tahkandit Limestone, undivided (Triassic and Permian); NSACLASS = 5035
   4035	TrPs - Sedimentary rocks (Triassic to Early Permian); NSACLASS = 5012
   4036	TrPzd - Metasedimentary, metavolcanic, and sedimentary rocks of the Doonerak area (Triassic to lower Paleozoic); NSACLASS = 5213
   4037	Ts - Clastic sedimentary rocks (Tertiary); NSACLASS = 640
   4038	Tv - Volcanic rocks (Tertiary); NSACLASS = 1103
   4039	Pzcm - Metamorphic rocks (Paleozoic?); NSACLASS = 5335
   4040	DZs - Metamorphosed sedimentary rocks (Devonian to Proterozoic); NSACLASS = 5561

   SOURCE

   SOURCE is a character (6 8 C) item found in both the polygon and arc attribute tables. The values are abbreviated codes representing the original source references for the polygon or arc feature. The format for SOURCE is XX###, where XX is a two letter code for the 1:250,000 scale quadrangle and ### is a three digit number (with leading zeros). All source codes with '001' are unspecified sources for water and ice features, often paper topographic maps, and DRG or DLG files. (Source: this data set)

   SOURCE values: BR003, BT004, BV003, CH003, CI006, CO003, CS003, CY006, FY004, LG005, TN009, and WI005, are defined as: Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map, SIM-XXX, scale 1:500,000.

   arcs

   Characteristics of the arc features in the geology and fold coverages are coded in the arc attribute table. Table <cov>.aat includes the following items: ARC-CODE, ARC-PARA1, and SOURCE. For explanation of SOURCE, see attribute definitions for polygons. (Source: this data set)

   ARC-CODE

   ARC-CODE is positive integer value (3 3 I) item in the arc attribute table. Values range discontinuously from 1 to 99. Values match one-for-one with geologic features (such as stratigraphic boundary, fault, etc.) Some ARC-CODE values have additional modifiers in item ARC-PARA1. (Source: this data set)

   Value	Definition
   1	Stratigraphic or intrusive contact, location certain
   4	Normal fault, location certain; if ARC-PARA1 = 1, then upthrown side is on right from origin
   7	Shoreline or riverbank
   10	Thrust fault, location certain, teeth on right from origin
   21	Syncline, location certain, digitized in direction of plunge; ARC-PARA1 equals angle of plunge, 0 is no plunge, 1 is plunge of unknown dip.
   24	Anticline, location certain, digitized in direction of plunge; ARC-PARA1 equals angle of plunge, 0 is no plunge, 1 is plunge of unknown dip
   30	Fault, sense of displacement uncertain, location certain
   31	Fault, sense of displacement uncertain, location approximate
   53	Concealed thust fault
   60	Concealed fault, sense of displacement uncertain
   99	Bounding line of coverage

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Labay, K.A.
   • Crews, Jesse
   • Wilson, F.H.
   • Shew, Nora
   • Hults, C.K.

2. Who also contributed to the data set?

   Jesse Crews (contractor), Keith A. Labay (contractor), Frederic H. Wilson (USGS)

3. To whom should users address questions about the data?

   U.S. Geological Survey
   c/o Frederic H. Wilson
   Geologist
   4200 University Drive
   Anchorage, Alaska 99508-4667
   U.S.A.
   

   907-786-7445 (voice)
   fwilson@usgs.gov
   

The data set represents part of a systematic effort to release geologic map data for the United States in a uniform manner. Geologic data in this series has been compiled from a wide variety of sources, published and unpublished, ranging from state and regional geologic maps to large-scale field mapping.

1. Where did the data come from?

2. What changes have been made?

   Date: 2006 (change 1 of 1)

   Linework for the geology and folds were digitized and incorporated into a geodatabase by Jesse Crews. The geology and folds were converted to coverages with the NSA standard data base structure by Keith Labay. The data was divided into 1:250,000 scale quadrangle extents. Each coverage is provided in UTM projection and geographic coordinates. The ARC/Info coverages have been exported to an interchange file format, .e00, and also converted to ArcView shape files.

   Person responsible for change:
   

   U.S. Geological Survey
   c/o Frederic H. Wilson
   Geologist
   4200 University Drive
   Anchorage, Alaska 99508-4667
   U.S.A.
   

   907-786-7448 (voice)
   fwilson@usgs.gov
   

1. How well have the observations been checked?

   The compiled geology was digitized from a hand drawn 1:500,000 scale paper map. Vector and polygon attributes were assigned. The digital data has been checked and the geologic map has been technically reviewed and edited.

2. How accurate are the geographic locations?

   This data is presented for use at a scale of 1:500,000.

3. How accurate are the heights or depths?

4. Where are the gaps in the data? What is missing?

   The complete data set consists of 14 different GIS coverages, 12 geology coverages and 2 fold coverages. There is also an associated relational database of geologic units. Each coverage has the extent of a 1:250,000 scale quadrangle. A graphic representation of the GIS database and a report with complete geologic descriptions is provided in .pdf format.

5. How consistent are the relationships among the observations, including topology?

   Each geology coverage is a network coverage containing attributed arcs and polygons. Each polygon has a coded attribute designating the mapped geologic unit. Faults, stratigraphic contacts, and other linear features are represented as arcs. When a fault is also a stratigraphic contact, only a single arc is present. Dangle arcs may be present (faults, dike, etc.)

Are there legal restrictions on access or use of the data?

Access_Constraints: None

Use_Constraints:

None. Acknowledment of the U.S. Geological Survey would be appreciated in products derived from these data.

1. Who distributes the data set? (Distributor 1 of 1)

   U.S. Geological Survey
   MS 902 Box 25286 Denver Federal Center
   Lakewood, CO 80225
   U.S.A.
   

   1-888-ASK-USGS (voice)
   

2. What's the catalog number I need to order this data set?

   Open-File Report 1304

3. What legal disclaimers am I supposed to read?

   This world-wide web publication was prepared by an agency of the United States Government. Neither the United States Government, nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability of responsibility for the accuracy, produce, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, reommendation, or favoring by the United States Government or any agency thereof.

4. How can I download or order the data?
   • Availability in digital form:

     Data format:	ARCE
     Network links:	<http://pubs.usgs.gov/of/2006/1304/>

   • Cost to order the data: There is no cost for the download of these digital files

Dates:

Last modified: 15-Sep-2006

Metadata author:

U.S. Geological Survey
c/o Nora Shew
4200 University Drive
Anchorage, Alaska 99508-4667
U.S.A.

907-786-7445 (voice)
nshew@usgs.gov

Metadata standard:

FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)