Identification_Information:
Citation:
Citation_Information:
Originator: P.K. Sims
Originator: J.M. O'Neill
Originator: Viki Bankey
Originator: E. Anderson
Publication_Date: 2004
Title: Precambrian basement geologic map of Montana-An interpretation of
aeromagnetic anomalies
Edition: version 1.0
Geospatial_Data_Presentation_Form: map
Series_Information:
Series_Name: USGS Scientific Investigations Map
Issue_Identification: Scientific Investigations Map 2829
Publication_Information:
Publication_Place: Denver, Colorado, U.S.A.
Publisher: United States Geological Survey
Online_Linkage: http://pubs.usgs.gov/sim/2829
Description:
Abstract:
Newly compiled aeromagnetic anomaly data of Montana, in conjunction with
the known geologic framework of basement rocks, have been combined to
produce a new interpretive geologic basement map of Montana.
Crystalline basement rocks compose the basement, but are exposed only in
the cores of mountain ranges in southwestern Montana. Principal
features deduced from the map are: (1) A prominent
northeast-trending, 200-km-wide zone of spaced negative anomalies, which
extends more than 700 km from southwestern Montana's Beaverhead
Mountains to the Canadian border and reflects suturing of the Archean
Mexican Hat Block against the Archean Wyoming Province along the
Paleoproterozoic Trans-Montana Orogen (new name) at about 1.9-1.8 Ga;
(2) North-northwest-trending magnetic lows in northeastern Montana,
which reflect the 1.9-1.8 Ga Trans-Hudson Orogen and truncate the older
Trans-Montana Zone; and (3) Subtle northwest- and west-trending negative
anomalies in central and western Montana, which represent the
northernmost segment of brittle-ductile transcurrent faults of the newly
recognized Mesoproterozoic Trans-Rocky Mountain fault system.
Structures developed in the Proterozoic provided zones of crustal
weakness reactivated during younger Proterozoic and Phanerozoic igneous
and tectonic activity. For example, the Trans-Montana Zone guided
basement involved thrust faulting in southwestern Montana during the
Sevier Orogeny. The Boulder Batholith and associated ore deposits and
the linear belt of alkaline intrusions to the northeast were localized
along a zone of weakness between the Missouri River suture and the
Dillon shear zone of the Trans-Montana Orogen. The northwest-trending
faults of Trans-Rocky Mountain system outline depocenters for
sedimentary rocks in the Belt Basin. This fault system provided zones
of weakness that guided Laramide uplifts during basement crustal
shortening. Northwest-trending zones have been locally reactivated
during Neogene basin-range extension.
Purpose:
This ARC/INFO dataset was developed to provide a geologic map GIS database
of the Precambrian basement of Montana for use in spatial analysis by a
variety of users.
Supplemental_Information:
Coverages included in this geospatial database:
faults2: line coverage of geologic faults
rocks2: polygon coverage of geologic units and contacts
mtpt: point coverage of symbols
supr_grp2: polygon coverage of areas containing major bodies of Belt
Supergroup (Yb) or Yellowjacket Formation (Yb)
Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 2004
Currentness_Reference: publication date
Status:
Progress: Complete
Maintenance_and_Update_Frequency: none currently planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -116.155203
East_Bounding_Coordinate: -103.640966
North_Bounding_Coordinate: 49.129673
South_Bounding_Coordinate: 44.248905
Keywords:
Theme:
Theme_Keyword_Thesaurus: American Geological Institute Glossary of
Geology
Theme_Keyword: aeromagnetic anomalies
Theme_Keyword: Archean
Theme_Keyword: basement
Theme_Keyword: batholiths
Theme_Keyword: intrusions
Theme_Keyword: mapping
Theme_Keyword: Montana Orogeny
Theme_Keyword: tectonics
Place:
Place_Keyword_Thesaurus: Board of Geographic Names
Place_Keyword: Montana
Place_Keyword: Bitterroot Range
Place_Keyword: Beaverhead Mountains
Place_Keyword: Rocky Mountains
Place_Keyword: Wyoming
Access_Constraints: none
Use_Constraints: none. Acknowledgment of the U.S. Geological Survey would
be appreciated in products derived from these data.
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Eric Anderson
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing address
Address: MS 964, Box 25046 DFC
City: Denver
State_or_Province: CO
Postal_Code: 80225-0046
Country: USA
Contact_Voice_Telephone: 303-236-5652
Contact_Facsimile_Telephone: 303-236-1425
Contact_Electronic_Mail_Address: ericanderson@usgs.gov
Browse_Graphic:
Browse_Graphic_File_Name:
http://pubs.usgs.gov/sim/2829/2829.pdf
Browse_Graphic_File_Description: graphic representation of map layout
Browse_Graphic_File_Type: PDF
Data_Set_Credit: Eric Anderson, U.S. Geological Survey, served as GIS
coordinator in the creation of the GIS database. Alex J. Donatich and
Gregory G. Green, U.S. Geological Survey, assisted in proofing the geology
and correcting the GIS database.
Native_Data_Set_Environment:
Microsoft Windows 2000 Version 5.0 (Build 2195) Service Pack 4
ESRI ArcCatalog 8.3.0.800; ARC/INFO version 8.3
Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
The database consists of newly generated data that were compiled on mylar
and then digitized in ARC/INFO. . This map was thoroughly reviewed for
conformity with U.S. Geological Survey editorial standards and
stratigraphic nomenclature.
Logical_Consistency_Report:
Map elements were visually checked by the authors and editor for overshoots,
undershoots, duplicate features, polygon attributes, and other errors.
Automated (ARC/INFO) routines were also used to check the databases for
polygon label errors and dangling arcs. The coverages were cleaned in
ARC/INFO to ensure logical consistency that is topologically clean. The map
was reviewed by other geologists for consistency with basic geologic
principles and general conformity to USGS mapping standards.
Completeness_Report:
This dataset is complete and includes the spatial coverages pertaining to
the geologic map.
Lineage:
Process_Step:
Process_Description: Paul Sims compiled the geology. Eric Anderson
digitized the geology. Gregory G. Green assisted in correcting the GIS
database. The digital database was quality checked by Alex J. Donatich.
The layout of the finished paper map was prepared by Alex J. Donatich
and checked by Paul Sims.
Process_Date: 2003-2004
Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Vector
Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Map_Projection:
Map_Projection_Name: Lambert Conformal Conic
Lambert_Conformal_Conic:
Standard_Parallel: 33.000000
Standard_Parallel: 45.000000
Longitude_of_Central_Meridian: -110.000000
Latitude_of_Projection_Origin: 0.000000
False_Easting: 0.000000
False_Northing: 0.000000
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: coordinate pair
Coordinate_Representation:
Abscissa_Resolution: 0.002048
Ordinate_Resolution: 0.002048
Planar_Distance_Units: meters
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1927
Ellipsoid_Name: Clarke 1866
Semi-major_Axis: 6378206.400000
Denominator_of_Flattening_Ratio: 294.978698
Entity_and_Attribute_Information:
Overview_Description:
Entity_and_Attribute_Overview:
The data are supplied in ARC/INFO export format and ArcView shapefile
format.
>Attribution of user-defined item ARC_TYPE in faults2.aat:
>strike-slip fault, certain
>strike-slip fault, inferred
>thrust fault (Laramide), certain
>thrust fault (Paleoproterozoic), certain
>thrust fault (Paleoproterozoic), inferred
>thrust fault (Sevier), certain
>Attribution of user-defined item ARC_TYPE in rocks2.aat:
>contact coincident with fault
>contact, certain
>contact, inferred
>map boundary
>Attribution of user-defined item FORMATION in rocks2.pat:
>Ag
>Agn
>Amh
>Ats
>Aum
>Czv
>VUs
>Wg
>Wgf
>Wsc
>XAr
>Xfb
>Xi
>Xm
>Xt
>Xw
>Xwv
>Yb
>Attribution of user-defined item EXPOSURE in rocks2.pat:
>no [indicates that unit is not exposed]
>yes [indicates that unit is exposed]
>Attribution of user-defined item TYPE in mtpt.pat:
>dip
>drill hole
>foliation
>strike slip
>Attribution of user-defined item SUPR_GRP in supr_grp.pat:
>Yb
>Yy
Entity_and_Attribute_Detail_Citation: none
Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing address
Address: Central Publications Group
Address: MS 902, Box 25046
Address: Denver Federal Center
City: Denver
State_or_Province: Colorado
Postal_Code: 80225
Country: USA
Contact_Voice_Telephone: (888)ASK-USGS
Contact_Electronic_Mail_Address: webmaster@geology.cr.usgs.gov
Distribution_Liability:
The U.S. Geological Survey (USGS) provides these geographic data "as is".
The USGS makes no guarantee or warranty concerning the accuracy of
information contained in the geographic data. The USGS further makes no
warranties, either expressed or implied, as to any other matter whatsoever,
including, without limitation, the condition of the product, or its fitness
for any particular purpose. The burden for determining fitness for use lies
entirely with the user. Although these data have been processed
successfully on computers at the USGS, no warranty, expressed or implied, is
made by the USGS regarding the use of these data on any other system, nor
does the fact of distribution constitute or imply any such warranty.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: ArcInfo interchange file and ArcInfo shapefile formats
Format_Version_Number: ArcInfo version 8.3
File_Decompression_Technique:
.tar.gz - UNIX gzip-compressed TAR file - use GNU zip and TAR to
extract
.ZIP - Windows ZIP archive - use Winzip, PKZip, or similar to extract
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name:
Fees: None
Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S.Geological Survey
Contact_Address:
Address_Type: mailing address
Address: USGS Information Services
Address: Box 25286
City: Denver
State_or_Province: CO
Postal_Code: 80225
Country: United States
Contact_Voice_Telephone: 1-888-ASK-USGS
Resource_Description: Scientific Investigations Map 2829 (plot-on-demand)
Distribution_Liability: none
Standard_Order_Process:
Non-digital_Form:
Available as one printed sheet. Order from USGS at the address listed
above or see for more
ordering information.
Fees:
For current prices please see
Metadata_Reference_Information:
Metadata_Date: 20040331
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Eric Anderson
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing address
Address: Denver Federal Center, MS 964
Address: Box 25046
City: Denver
State_or_Province: Colorado
Postal_Code: 80225
Country: USA
Contact_Voice_Telephone: (303) 236-5652
Contact_Electronic_Mail_Address: ericanderson@usgs.gov
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Access_Constraints: None
Metadata_Use_Constraints: None