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Generalized Geologic Map of the Conterminous United States

Metadata also available as - [Outline] - [Parseable text] - [XML] - [DIF]

Frequently-anticipated questions:


What does this data set describe?

Title: Generalized Geologic Map of the Conterminous United States
Abstract:
This data set contains boundaries and tags for major geologic units in the conterminous United States. In addition to the polygons representing the areal extent of geologic units, it identifies boundaries of metamorphic provinces, major faults, calderas, impact structures, and generalized limits of continental glaciation. The data depict the geology of the bedrock that lies at or near the land surface, but not the distribution of surficial materials such as soils, alluvium, and glacial deposits. This is a revised version of the April 2004 data set. This map complements the Generalized Geologic Map of Alaska, Hawaii, Puerto Rico, and the U.S. Virgin Islands by Reed and Bush.

The data are generalized from a compilation prepared for use in the Geologic Map of North America, to be published in hard copy by the Geological Society of America and released as a digital file by the U.S. Geological Survey.

Supplemental_Information:
The data set for the Geologic Map of the Conterminous United States consists of nine data layers. The data layers for faults and glacial limit lines are included in two different versions. The data are available as shapefiles, ArcInfo Export files, or graphics files (includes PDF, EPS, and AI formats). The data layers are distributed and should be used together. All the data layers were created as ARCINFO coverages and converted to other formats for distribution purposes. The following files are included:
 Calderl075 - Outlines of major calderas and impact structures
 Faultgl075 - Fault lines, with line decorations*
 Faultl075 - Fault lines, without line decorations**
 Geolgym075 - Geologic units, as polygons
 Geotxtl075 - Graphic representation of geologic unit text*
 Glacagl075 - Generalized glacial limit lines, with line decorations*
 Glacall075 - Generalized glacial limit lines, without line decorations**
 Impactx075 - Impact structure locations, as points
 Metfacp075 - Areas and facies types of metamorphism, as polygons

* these files are not 'true' ArcInfo coverages; they are graphic
  representations of symbols and text used on the geologic map.   These
  files should be used to produce appropriately symbolized graphics.
  The decorations and text only appear correctly in Lambert Azimuthal
  Equal Area projection.  The parameters for the projection are:
        Projection                        Lambert Azimuthal Equal Area
        Datum                             NAD83
        Spheroid                          GRS1980
        Units                             Meters
        Radius of the sphere of reference  6370997
        Longitude of center projection    -100
        Latitude of center of projection  45

** these files are the same as the files marked with * but do not
   include the line decorations.  They are the 'true' fault and glacial
   limit line ArcInfo coverages.  These files should be used for data
   analysis.
Also distributed with the data is the shadeset, geoshade.shd.

Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government

Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, some ArcInfo-specific terminology is included for clarity and expediency.

  1. How should this data set be cited?

    John C. Reed, Jr., and Bush, Charles A. , 200512, Generalized Geologic Map of the Conterminous United States: U.S. Geological Survey, Denver, CO.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -124.73301687
    East_Bounding_Coordinate: -66.95458457
    North_Bounding_Coordinate: 50.00006074
    South_Bounding_Coordinate: 24.51789429

  3. What does it look like?

    <http://pubs.usgs.gov/atlas/geologic/usgeoplot.pdf> (PDF)
    An image of the map of the United States.
    <http://pubs.usgs.gov/atlas/geologic/usgeoexp.pdf> (PDF)
    An image of the map explanation.

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

    Beginning_Date: 01-Mar-1998
    Ending_Date: 01-Jun-1999
    Currentness_Reference: Compilation date

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

    Geospatial_Data_Presentation_Form: Map

  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. It contains the following vector data types (SDTS terminology):

      • String (69825)
      • String (1259)
      • String (1098)
      • String (91)
      • String (1206)
      • GT-polygon composed of chains (121)
      • String (63)
      • Point (32)
      • GT-polygon composed of chains (2777)
      • String (10599)

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

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.0000094433083. Longitudes are given to the nearest 0.0000094433083. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is GRS1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222.

  7. How does the data set describe geographic features?

    Fault, with line decorations (described by faultgl075.aat or faultgl.dbf)
    A fault is a fracture or fracture zone in the Earth's crust along which rocks on one side have moved significantly with respect to those on the other side. This data set includes both the faults and the line decorations. (Source: U.S. Geological Survey)

    Shape
    The representation of the entity in the data. (Source: U.S. Geological Survey)

    ValueDefinition
    Polyline1-dimensional element that may or may not surround a 2-dimensional element.

    Fnode#
    Internal sequence number of the from-node. (Source: U.S. Geological Survey)

    Range of values
    Minimum:2
    Maximum:50400

    Tnode#
    Internal sequence number of the to-node. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:50401

    Lpoly#
    Internal sequence number of the left polygon. (Source: U.S. Geological Survey)

    Range of values
    Minimum:-1
    Maximum:0

    Rpoly#
    Internal sequence number of the right polygon. (Source: U.S. Geological Survey)

    Range of values
    Minimum:-1
    Maximum:0

    Length
    The length of the line in coverage units. In the distributed file, coverage units represent decimal degrees. (Source: U.S. Geological Survey)

    Range of values
    Minimum:150.188
    Maximum:430125.400

    Faultgl075# or Faultgl_
    Internal feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:69825

    Faultgl075-id or Faultgl_id
    User-assigned feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:4
    Maximum:71912

    Code
    The type of fault represented in the data set. (Source: U.S. Geological Survey)

    ValueDefinition
    12Fault
    13Thrust fault
    14Normal fault
    16Low angle detachment fault
    17Inferred fault

    Text
    The type of fault. (Source: U.S. Geological Survey)

    ValueDefinition
    FaultA fault is a fracture or fracture zone in the Earth's crust along which rocks on one side have moved significantly with respect to those on the other side.
    Thrust FaultA thrust fault is a flat or gently inclined fault (less than 45 degrees) along which the rocks above have moved relative to the rocks below.
    Normal FaultA normal fault is a steeply inclined fault (usually more than 45 degrees) where rocks above the fault have moved down relative to those below the fault.
    Low Angle Detachment FaultA large, shallowly-inclined normal fault formed during extension of the Earth's crust.
    Inferred FaultThe existence and location of the fault are inferred from indirect evidence.

    Fault, without line decorations (described by faultl075.aat or faultl.dbf)
    A fault is a fracture or fracture zone in the Earth's crust along which rocks on one side have moved significantly with respect to those on the other side. (Source: U.S. Geological Survey)

    Shape
    The representation of the entity in the data. (Source: U.S. Geological Survey)

    ValueDefinition
    Polyline1-dimensional element that may or may not surround a 2-dimensional element.

    Fnode#
    Internal sequence number of the from-node. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:1

    Tnode#
    Internal sequence number of the to-node. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:4

    Lpoly#
    Internal sequence number of the left polygon. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:0

    Rpoly#
    Internal sequence number of the right polygon. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:0

    Length
    The length of the line in coverage units. In the distributed file, coverage units represent decimal degrees. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0.10873
    Maximum:342987.14268

    Faultl075# or Faultl_
    Internal feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:1259

    Faultl075-id or Faultl_id
    User-assigned feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:83
    Maximum:1603

    Code
    The type of fault represented in the data set. (Source: U.S. Geological Survey)

    ValueDefinition
    12Fault
    13Thrust fault
    14Normal fault
    16Low angle detachment fault
    17Inferred fault

    Text
    The type of fault. (Source: U.S. Geological Survey)

    ValueDefinition
    FaultA fault is a fracture or fracture zone in the Earth's crust along which rocks on one side have moved significantly with respect to those on the other side.
    Thrust FaultA thrust fault is a flat or gently inclined fault (less than 45 degrees) along which the rocks above have moved relative to the rocks below.
    Normal FaultA normal fault is a steeply inclined fault (usually more than 45 degrees) where rocks above the fault have moved down relative to those below the fault.
    Low Angle Detachment FaultA large, shallowly-inclined normal fault formed during extension of the Earth's crust.
    Inferred FaultThe existence and location of the fault are inferred from indirect evidence.

    Generalized glacial limit line, with line decorations (described by glacagl075.aat or glacagl.dbf)
    A line showing the generalized southern limit of Wisconsin and pre- Wisconsin glaciation in the United States. For display purposes, tics are included along the line for line decorations. (Source: U.S. Geological Survey)

    Shape
    The representation of the entity in the data. (Source: U.S. Geological Survey)

    ValueDefinition
    Polyline1-dimensional element that may or may not surround a 2-dimensional element.

    Fnode#
    Internal sequence number of the from-node. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:2140

    Tnode#
    Internal sequence number of the to-node. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:2141

    Lpoly#
    Internal sequence number of the left polygon. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:0

    Rpoly#
    Internal sequence number of the right polygon. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:0

    Length
    The length of the line in coverage units. In the distributed file, coverage units represent decimal degrees. (Source: U.S. Geological Survey)

    Range of values
    Minimum:8.990
    Maximum:1291296.000

    Glacagl075# or Glacagl_
    Internal feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:1098

    Glacagl075-id (Included in Export format file only.)
    User-assigned feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:1074

    Code
    Values representing the limits of glacial advance at two selected times. (Source: U.S. Geological Survey)

    ValueDefinition
    1Wisconsin glacial limit.
    2Pre-Wisconsin glacial limit.

    Glacial_li
    The type of glacial limit line. (Source: U.S. Geological Survey)

    ValueDefinition
    Wisconsin Glacial LimitA generalized line showing the maximum extent of glaciation during Wisconsin time, 35,000 to 11,150 years ago.
    Pre-Wisconsin Glacial LimitA generalized line showing the maximum extent of glaciation prior to Wisconsin time, earlier than 11,150 years ago.

    Glacial limit line, without line decorations (described by glacall075.aat or glacall.dbf)
    A line showing the generalized southern limit of Wisconsin and pre- Wisconsin glaciation in the United States. (Source: U.S. Geological Survey)

    Shape
    The representation of the entity in the data. (Source: U.S. Geological Survey)

    ValueDefinition
    Polyline1-dimensional element that may or may not surround a 2-dimensional element.

    Fnode#
    Internal sequence number of the from-node. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:0

    Tnode#
    Internal sequence number of the to-node. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:0

    Lpoly#
    Internal sequence number of the left polygon. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:0

    Rpoly#
    Internal sequence number of the right polygon. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:0

    Length
    The length of the line in coverage units. In the distributed file, coverage units represent decimal degrees. (Source: U.S. Geological Survey)

    Range of values
    Minimum:5125.62160
    Maximum:1291295.86094

    Glacall075# or Glacall075
    Internal feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:91

    Glacall075-id (Included in Export format file only.)
    User-assigned feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:91

    Code
    Values representing the limits of glacial advance at two selected times. (Source: U.S. Geological Survey)

    ValueDefinition
    1Wisconsin glacial limit.
    2Pre-Wisconsin glacial limit.

    Glacial_li
    The type of glacial limit line. (Source: U.S. Geological Survey)

    ValueDefinition
    Wisconsin Glacial LimitA generalized line showing the maximum extent of glaciation during Wisconsin time, 35,000 to 11,150 years ago.
    Pre-Wisconsin Glacial LimitA generalized line showing the maximum extent of glaciation prior to Wisconsin time, earlier than 11,150 years ago.

    Text labels (described by geotxtl075.aat or geotxtl.dbf)
    Text labels for the geology coverage, represented as lines. Standard geologic symbols are included. (Source: U.S. Geological Survey)

    Shape
    The representation of the entity in the data. (Source: U.S. Geological Survey)

    ValueDefinition
    Polyline1-dimensional element that may or may not surround a 2-dimensional element.

    Fnode#
    Internal sequence number of the from-node. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:131

    Tnode#
    Internal sequence number of the to-node. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:132

    Lpoly#
    Internal sequence number of the left polygon. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:0

    Rpoly#
    Internal sequence number of the right polygon. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:0

    Length
    The length of the line in coverage units. In the distributed file, coverage units represent decimal degrees. (Source: U.S. Geological Survey)

    Range of values
    Minimum:2373.982
    Maximum:117346.700

    Geotxtl075# or Geotxtl_
    Internal feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:1206

    Geotxtl075-id or Geotxtl_id
    User-assigned feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:1105

    Areas of amphibolite or blueschist facies metamorphism (described by metfacp075.pat or metfacp.dbf).
    Metamorphism is the alteration of texture or composition in a rock by pressure, heat, or water. (Source: U.S. Geological Survey)

    Shape
    The representation of the entity in the data. (Source: U.S. Geological Survey)

    ValueDefinition
    Polygon2-dimensional element.

    Area
    The size of the shape in square coverage units. In the distributed file, coverage units represent square decimal degrees. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0.000
    Maximum:15.256

    Perimeter
    The perimeter of the shape in coverage units. In the distributed file, coverage units represent decimal degrees. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0.089
    Maximum:55.468

    Metfacp075# or Metfacpc_
    Internal feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:2
    Maximum:122

    Metfacp075-id or Metfacpc_i
    User-assigned feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:122

    Metam-fac
    The type of facies metamorphism. (Source: U.S. Geological Survey)

    ValueDefinition
    <blank>An area where metamorphism is not mapped.
    Amphibolite Facies MetamorphismA metamorphic mineral assemblage formed under medium temperature and medium to high pressure.
    Blueschist Facies MetamorphismA metamorphic mineral assemblage formed under low temperature and high pressure.

    Calderas and impact structures (described by calderl075.aat or calderl.dbf)
    Outlines of major calderas and impact structures. A caldera is a large, generally circular depression at the summit of a volcano formed when magma is withdrawn or erupted from a shallow underground magma reservoir. An impact structure is a crater formed by the impact of a meteoroid, asteroid, or comet with the Earth. (Source: U.S. Geological Survey)

    Shape
    The representation of the entity in the data. (Source: U.S. Geological Survey)

    ValueDefinition
    Polyline1-dimensional element that may or may not surround a 2-dimensional element.

    Fnode#
    Internal sequence number of the from-node. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:47

    Tnode#
    Internal sequence number of the to-node. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:47

    Lpoly#
    Internal sequence number of the left polygon. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:0

    Rpoly#
    Internal sequence number of the right polygon. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:0

    Length
    The length of the line in coverage units. In the distributed file, coverage units represent decimal degrees. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1600.429
    Maximum:302426.800

    Calderl075# or Calderl_
    Internal feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:63

    Calderl075-id or Calderl_id
    User-assigned feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:104
    Maximum:49926

    Code
    The type of caldera boundary or impact structure extent. (Source: U.S. Geological Survey)

    ValueDefinition
    17Caldera Boundary
    18Caldera Boundary, uncertain
    19Extent of large, buried impact structure.

    Structure_
    The type of structure (Source: U.S. Geological Survey)

    ValueDefinition
    Caldera BoundaryThe areal extent of the caldera at the surface.
    Caldera Boundary, uncertainThe estimated areal extent of the caldera.
    Extent of large, buried impact structureThe estimated extent of the impact structure.

    Impact site (described by impactx075.pat or impactx.dbf)
    The center of an impact structure. An impact structure is a crater formed by the impact of a meteoroid, asteroid, or comet with the Earth. (Source: U.S. Geological Survey)

    Shape
    The representation of the entity in the data. (Source: U.S. Geological Survey)

    ValueDefinition
    Point0-dimensional element.

    Area
    The size of the shape in square coverage units. In the distributed file, coverage units represent square decimal degrees. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0.000
    Maximum:0.000

    Perimeter
    The perimeter of shape in coverage units. In the distributed file, coverage units represent decimal degrees. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0.000
    Maximum:0.000

    Impactx075# or Impactx_
    Internal feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:32

    Impactx075-id or Impactx_id
    User-assigned feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:47
    Maximum:78

    Structure_
    Indicates whether a site is an impact structure or a suspected impact structure. (Source: U.S. Geological Survey)

    ValueDefinition
    Impact StructureA site where the structure has been positively determined to have been created by the impact of a meteoroid, asteroid, or comet with the Earth.
    Suspected impact structureA site where the structure may have been created by the impact of a meteoroid, asteroid, or comet with the Earth. Positive determination of the means of formation has not been made

    Id_num
    The identification number for the impact structure. Suspected impact structures have a value of 0. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:17

    Name
    The name or location of the impact site. (Source: U.S. Geological Survey)

    There is no predefined set of impact structure names or locations.

    Latitude
    The latitude at the center of the impact site, in degrees and minutes. (Source: U.S. Geological Survey)

    Range of values
    Minimum:2902'
    Maximum:4736'

    Longitude
    The longitude at the center of the impact site, in degrees and minutes. (Source: U.S. Geological Survey)

    Range of values
    Minimum:7250'
    Maximum:11101'

    Diameter_m
    The diameter of the impact site in miles. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0.00
    Maximum:60.00

    Age
    The age of the impact site in years. (Ma indicates a million years. For example, 100 Ma equals 100,000,000 years.) (Source: U.S. Geological Survey)

    There is no predefined set of ages.

    Remarks
    The basis of site identification. (Source: U.S. Geological Survey)

    There is no predefined set of remarks.

    Geologic unit (described by geolgym075.pat or geolgyp.dbf)
    Rock and material that lies at or near the land surface, but not surficial materials such as soils, alluvium, and glacial deposits. The units are defined by sedimentary, volcanic, plutonic, or metamorphic rock types and by their geologic age. The Text attribute is included to provide a method for generating the appropriate map symbols for display and publication purposes. (Source: U.S. Geological Survey)

    Shape
    The representation of the entity in the data. (Source: U.S. Geological Survey)

    ValueDefinition
    Polygon2-dimensional element.

    Area
    The size of the shape in square coverage units. In the distributed file, coverage units represent square decimal degrees. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0.00000
    Maximum:60.48843

    Perimeter
    The perimeter of shape in coverage units. In the distributed file, coverage units represent decimal degrees. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0.00543
    Maximum:204.79648

    Geolgyp075# or Geolgym075
    Internal feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:2
    Maximum:2788

    Geolgyp075-id or Geolgymc_i
    User-assigned feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:3500

    Geology
    The standard geologic symbol for the rock type. (Source: U.S. Geological Survey)

    ValueDefinition
    (See table under Text)(See table under Text)

    Mapunit_sy
    A letter code representing the geology. (Source: U.S. Geological Survey)

    ValueDefinition
    (See table under Text)(See table under Text)

    Text
    The value recognized by the program GSMCAD and used to create the special font for geologic symbols, e.g. %217 represents the geologic symbol for mesozoic. Because standard fonts available in ArcInfo do not have the special symbols used for geologic time periods, the symbols were created in GSMCAD and exported as arcs. (Source: U.S. Geological Survey)

    ValueDefinition
    (See table below)The values for Text are listed below, along with the associated values for the Mapunit_sy attribute and the values for the Geology attribute.
    
    MAPUNIT_SY  TEXT       GEOLOGY
    -------------------------------------------------------------------
    Q           Q          Quaternary deposits
    nT          nT         Neogene sedimentary rocks
    pgT         pgT        Paleogene sedimentary rocks
    KT          KT         Cretaceous and Tertiary sedimentary rocks
    Mz          %217       Mesozoic sedimentary rocks
    lMz         l%217      Lower Mesozoic (Triassic and Jurassic)
                             sedimentary rocks
    uPz         u%216      Upper Paleozoic (Pennsylvanian and
                             Permian) sedimentary rocks
    PzMz        %216%217   Paleozoic and Mesozoic sedimentary rocks
    mPz         m%216      Middle Paleozoic (Silurian, Devonian, and
                             Mississippian) sedimentary rocks
    Pz          %216       Paleozoic sedimentary rocks
    lPz         l%216      Lower Paleozoic (Cambrian and Ordovician)
                             sedimentary rocks
    ZPz         Z%216      Late Proterozoic and lower Paleozoic
                             sedimentary rocks
    Z           Z          Late Proterozoic sedimentary rocks
    Y           Y          Middle Proterozoic sedimentary rocks
    P_          %215       Proterozoic sedimentary rocks
    X           X          Early Proterozoic sedimentary rocks
    A           A          Archean sedimentary rocks
    K           K          Cretaceous sedimentary rocks
    Qv          Qv         Quaternary volcanic rocks
    nTv         nTv        Neogene volcanic rocks
    pgTv        pgTv       Paleogene volcanic rocks
    Kv          Kv         Cretaceous volcanic rocks
    Mzv         %217v      Mesozoic volcanic rocks
    lMzv        l%217v     Lower Mesozoic (Triassic and Jurassic)
                             volcanic rocks
    PzMzv       %216%217v  Paleozoic and Mesozoic volcanic rocks
    mPzv        m%216v     Middle Paleozoic volcanic rocks
    lPzv        l%216v     Lower Paleozoic volcanic rocks
    ZPzv        Z%216v     Late Proterozoic and lower
                             Paleozoic volcanic rocks
    Zv          Zv         Late Proterozoic volcanic rocks
    Yv          Yv         Middle Proterozoic volcanic rocks
    Xv          Xv         Early Proterozoic volcanic rocks
    pgTg        pgTg       Paleogene granitic rocks
    pgTi        pgTi       Paleogene intermediate rocks
    pgTm        pgTm       Paleogene mafic rocks
    KTg         KTg        Cretaceous and Tertiary granitic rocks
    Kg          Kg         Cretaceous granitic rocks
    Mzg         %217g      Mesozoic granitic rocks
    lMzg        l%217g     Lower Mesozoic granitic rocks
    lMzm        l%217m     Lower Mesozoic mafic rocks
    lMzu        l%217u     Lower Mesozoic ultramafic rocks
    uPzg        u%216g     Upper Paleozoic granitic rocks
    mPzg        m%216g     Middle Paleozoic granitic rocks
    mPzm        m%216m     Middle Paleozoic mafic rocks
    lPzg        l%216g     Lower Paleozoic granitic rocks
    ZPzg        Z%216g     Late Proterozoic and lower Paleozoic
                             granitic rocks
    ZPzm        Z%216m     Late Proterozoic and lower Paleozoic
                             mafic rocks
    P_g         %215g      Proterozoic granitic rocks
    Yg          Yg         Middle Proterozoic granitic rocks
    Ym          Ym         Middle Proterozoic mafic rocks
    Ya          Ya         Middle Proterozoic anorthositic rocks
    Xg          Xg         Early Proterozoic granitic rocks
    Xm          Xm         Early Proterozoic mafic rocks
    Ag          Ag         Archean granitic rocks
    Zg          Zg         Late Proterozoic granitic rocks
    n           n          Gneiss, age uncertain
    ZPzn        Z%216n     Late Proterozoic and lower Paleozoic gneiss
    Yn          Yn         Middle Proterozoic gneiss
    Xn          Xn         Early Proterozoic gneiss
    An          An         Archean gneiss
    PzMzm       %216%217m  Paleozoic and Mesozoic mafic rocks
    Tv          Tv         Tertiary volcanic rocks
    nTg         nTg        Neogene granitic rocks
    H2o         H2o        Water body
    
    

    Geoshade
    The shade pattern number from the ARCINFO shadeset geoshade.shd. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:231

    Red
    Value of red used to produce map unit colors. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:255

    Green
    Value of green used to produce map unit colors. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:255

    Blue
    Value of blue used to produce map unit colors. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0
    Maximum:255

    Rock or geologic deposit boundary line (described by geolgym075.aat or geolgyl.dbf)
    Line separating different geologic units. (Source: U.S. Geological Survey)

    Shape
    The representation of the entity in the data. (Source: U.S. Geological Survey)

    ValueDefinition
    Polyline1-dimensional element that may or may not surround a 2-dimensional element.

    Fnode#
    Internal sequence number of the from-node. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:9432

    Tnode#
    Internal sequence number of the to-node. (Source: U.S. Geological Survey)

    Range of values
    Minimum:2
    Maximum:9432

    Lpoly#
    Internal sequence number of the left polygon. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:2778

    Rpoly#
    Internal sequence number of the right polygon. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:2768

    Length
    The length of the line in coverage units. In the distributed file, coverage units represent decimal degrees. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0.00005
    Maximum:16.18611

    Geolgyl075# or Geolgym075
    Internal feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:10599

    Geolgyl075-id or Geolgym_id
    User-assigned feature number. (Source: U.S. Geological Survey)

    Range of values
    Minimum:3
    Maximum:49939

    Code
    The type of geologic boundary. (Source: U.S. Geological Survey)

    ValueDefinition
    11Contact
    12Fault (copied in fault file)
    13Thrust fault (copied in fault file)
    14Normal fault (copied in fault file)
    16Low angle detachment fault (copied in fault file)
    21Shoreline
    23International boundary

    Text
    The type of geologic boundary. (Source: U.S. Geological Survey)

    ValueDefinition
    ContactThe surface where two different kinds of rocks meet.
    FaultA fault is a fracture or fracture zone in the Earth's crust along which rocks on one side have moved significantly with respect to those on the other side. This data set includes both the faults and the line decorations.
    Thrust faultA thrust fault is a flat or gently inclined fault (less than 45 degrees) along which the rocks above have moved relative to the rocks below.
    Normal faultA normal fault is a steeply inclined fault (usually more than 45 degrees) where rocks above the fault have moved down relative to those below the fault.
    Low angle detachment faultA large, shallowly-inclined normal fault formed during extension of the Earth's crust.
    ShorelineThe line where geologic map units are terminated by a body of water.
    International boundaryThe line where geologic map units are terminated by an international boundary.


Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

    • John C. Reed, Jr.
    • Charles A. Bush

  2. Who also contributed to the data set?

    Nancy Shock, Digital Cartographer, U.S. Geological Survey, assisted in the digital compilation of this map.

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

    John C. Reed, Jr.
    U.S. Geological Survey
    Mail Stop 913, Box 25046
    Lakewood, CO 80225
    USA

    303-236-1276 (voice)
    303-236-0214 (FAX)
    jreed@usgs.gov


Why was the data set created?

These data have been prepared with a degree of detail appropriate for viewing at a scale of 1:7,500,000. Because of the degree of generalization required (generalization based on compilation scale), the data are intended primarily for display and for regional and national analysis, rather than for more detailed analysis in specific areas.

No responsibility is assumed by the U.S. Geological Survey in the use of these data.


How was the data set created?

  1. From what previous works were the data drawn?

    DNAG-A (source 1 of 10)
    Bally, A.W. (ed.), and Palmer, A.R. (ed.), 1989, The Geology of North America; an Overview: The Geology of North America v. A, 619 p., Geological Society of America, Boulder, CO.

    Type_of_Source_Media: Paper
    Source_Contribution: Line work and attributes.

    DNAG-G (source 2 of 10)
    Buchfiel, B.C. (ed.), Lipman, P.W. (ed.), and Zoback, M.L. (ed.), 1992, The Cordilleran Orogen, Conterminous U.S.: The Geology of North America v. G-3, 724 p., Geological Society of America, Boulder, CO.

    Type_of_Source_Media: Paper
    Source_Scale_Denominator: 5,000,000
    Source_Contribution: Line work and attributes.

    DNAG-F (source 3 of 10)
    Hatcher, R.D. (ed.), Viele, G.W. (ed.), and Thomas, W.A., (ed.), 1989, Appalachian-Ouachita Orogen in the United States: The Geology of North America v. F-2, 767 p., Geological Society of America, Boulder, CO.

    Type_of_Source_Media: Paper
    Source_Scale_Denominator: 5,000,000
    Source_Contribution: Line work and attributes.

    GMUS (source 4 of 10)
    King, P.B., and H.M., Beikman, 1974, Geologic map of the United States (exclusive of Alaska and Hawaii): U.S. Geological Survey, Reston, VA.

    Type_of_Source_Media: Paper
    Source_Scale_Denominator: 2,500,000
    Source_Contribution: Line work and attributes.

    DNAG-C (source 5 of 10)
    Reed, J.C., Jr. (ed.), Bickford, M.E. (ed.), Houston, R.S. (ed.), Link, P.K. (ed.), Rankin, D.W. (ed.), Sims, P.K. (ed.), and Van Schmus, W.R. (ed.), 1993, Precambrian: Conterminous U.S.: The Geology of North America v. C-2, 657 p., Geological Society of America, Boulder, CO.

    Type_of_Source_Media: Paper
    Source_Scale_Denominator: 5,000,000
    Source_Contribution: Line work and attributes.

    DNAG-J (source 6 of 10)
    Salvador, A., ed, 1991, The Gulf of Mexico Basin: The Geology of North America v. J, 568 p., Geological Society of America, Boulder, CO.

    Type_of_Source_Media: Paper
    Source_Contribution: Line work and attributes.

    DNAG-I (source 7 of 10)
    Sheridan, R.E. (ed.), and Grow, J.A. (ed.), 1988, The Atlantic Continental Margin, U.S.: The Geology of North America v. I-2, 632 p., Geological Society of America, Boulder, CO.

    Type_of_Source_Media: Paper
    Source_Contribution: Line work and attributes.

    SP190 (source 8 of 10)
    Silver, L.T. (ed.), and Schultz, P.H. (ed.), 1982, Geological Implications of Impacts of Large Asteroids and Comets on the Earth: Geological Society of America Special Paper 190, 528 p.: Geological Society of America, Boulder, CO.

    Type_of_Source_Media: Paper
    Source_Contribution: Impact structures

    DNAG-D (source 9 of 10)
    Sloss, L.L. (ed.), 1988, Sedimentary Cover, North American Craton, U.S: The Geology of North America v. D-2, 506 p., Geological Society of America, Boulder, CO.

    Type_of_Source_Media: Paper
    Source_Contribution: Line work and attributes.

    ATLAS-GEO_200404 (source 10 of 10)
    John C. Reed, Jr., and Bush, Charles A. , 200404, Generalized Geologic Map of the Conterminous United States: U.S. Geological Survey, Denver, CO.

    Type_of_Source_Media: Online
    Source_Contribution: Spatial and attribute information.

  2. How were the data generated, processed, and modified?

    Date: 1999 (process 1 of 6)
    The geologic unit polygons (geolgym075), faults (faultl075), generalized glacial limit lines (glacall075), boundaries of metamorphic provinces (metfacp075), calderas (calderl075), and impact structures (impactx075) were created using the following procedures:

    Data were compiled on scale-stable clear film at various scales. The lines and points were then digitized and georeferenced using the computer program GSMCAD, written by Van S. Williams, USGS. The program is available at no charge at <http://geology.cr.usgs.gov/maps/software.html>. Polygons, lines, and point features were attributed in GSMCAD.

    Person who carried out this activity:

    John C. Reed, Jr.
    U.S. Geological Survey
    Mail Stop 913, Box 25046, Denver Federal Center
    Lakewood, CO 80225
    USA

    303-236-1276 (voice)
    303-236-0214 (FAX)
    jreed@usgs.gov

    Data sources used in this process:
    • DNAG-A
    • DNAG-G
    • DNAG-F
    • GMUS
    • DNAG-C
    • DNAG-J
    • DNAG-I
    • SP190
    • DNAG-D

    Date: 1999 (process 2 of 6)
    The data were exported from GSMCAD into ArcInfo Generate format, and were imported into ArcInfo coverages using AML routines provided with GSMCAD.

    Person who carried out this activity:

    John C. Reed, Jr.
    U.S. Geological Survey
    Mail Stop 913, Box 25046, Denver Federal Center
    Lakewood, CO 80225
    USA

    303-236-1276 (voice)
    303-236-0214 (FAX)
    jreed@usgs.gov

    Date: 1999 (process 3 of 6)
    Errors in polygon labeling were checked using the LABELERROR routine in ARCPLOT. Node errors were checked using ARCEDIT routines. Colored plots were made to make final checks of the overall coverages.

    Person who carried out this activity:

    Charles A. Bush
    U.S. Geological Survey
    Mail Stop 913, Box 25046, Denver Federal Center
    Lakewood, CO 80225
    USA

    303-236-4723 (voice)
    303-236-0214 (FAX)
    cbush@usgs.gov

    Date: 1999 (process 4 of 6)
    Supplementary graphical coverages were created for the faults (faultgl075) and generalized glacial limit lines (glacagl075). These are the same as faultl075 and glacall075 except decoration lines have been added for display purposes. Another coverage was created containing arcs that represent text labels for the polygons (geotxtl075). This is also for display purposes.

    Person who carried out this activity:

    Charles A. Bush
    U.S. Geological Survey
    Mail Stop 913, Box 25046, Denver Federal Center
    Lakewood, CO 80225
    USA

    303-236-4723 (voice)
    303-236-0214 (FAX)
    cbush@usgs.gov

    Date: 18-Mar-2004 (process 5 of 6)
    The glacial limit attribute was changed in the file containing the generalized glacial limit lines with line decorations (glacagl075) and in the file containing generalized glacial limit lines without line decorations (glacall075). Wisconsin Glacial Limit Line was changed to Wisconsin Glacial Limit and Pre-Wisconsin Glacial Limit Line was changed to Pre-Wisconsin Glacial Limit.

    Person who carried out this activity:

    Charles A. Bush
    U.S. Geological Survey
    Mail Stop 913, Box 25046, Denver Federal Center
    Lakewood, CO 80225
    USA

    303-236-4723 (voice)
    303-236-0214 (FAX)
    cbush@usgs.gov

    Data sources produced in this process:
    • ATLAS-GEO_200404

    Date: 26-Apr-2005 (process 6 of 6)
    Attributes for map units were revised to use age terms ("Early," "Middle," and "Late"), to modify Proterozoic units and position terms ("lower," "middle," and "upper"), and to modify Paleozoic and Mesozoic units.

    Person who carried out this activity:

    Charles A. Bush
    U.S. Geological Survey
    Mail Stop 913, Box 25046, Denver Federal Center
    Lakewood, CO 80225
    USA

    303-236-4723 (voice)
    303-236-0214 (FAX)
    cbush@usgs.gov

    Data sources used in this process:
    • ATLAS-GEO_200404

  3. What similar or related data should the user be aware of?

    John C. Reed, Jr., and Bush, Charles A. , 200512, Generalized Geologic Map of Alaska, Hawaii, Puerto Rico, and the U.S. Virgin Islands: U.S. Geological Survey, Denver, CO.

    Online Links:


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    The line attributes were manually checked by assigning unique line types to the values and then plotting the data. The plots were then compared to the source.

    The polygon attributes were checked by visually comparing the final colored plots to maps at various larger scales.

  2. How accurate are the geographic locations?

    The accuracy of the original data was checked by comparing the digital files to several data sources. Both the line work and the polygon labels were checked against the source compilation.

  3. How accurate are the heights or depths?

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

    This data set contains map unit boundaries and codes for the 48 conterminous States. Boundaries and codes are included for geologic units, metamorphic facies, limits of glacial advance, impact structures, caldera boundaries, and major faults.

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

    Polygon and node topology are present. All polygons are labeled and were tested by using the ArcInfo command LABELERRORS. All polygons were checked for closure, node errors, overshoots, undershoots, dangles and intersections using ArcInfo routines. The ArcInfo commands BUILD and CLEAN were run to ensure the topological consistency of the data set.


How can someone get a copy of the data set?

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

Access_Constraints: None
Use_Constraints:
None. Acknowledgment of the National Atlas of the United States of America and (or) 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, Geologic Division, Central Publications Group
    MS 902, Box 25046, Denver Federal Center
    Lakewood, CO 80225
    USA

    303-236-4845 (voice)
    tpinto@usgs.gov

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

  3. What legal disclaimers am I supposed to read?

    Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made by the U.S. Geological Survey regarding the utility of the data on any other system, nor shall the act of distribution constitute any such warranty. No responsibility is assumed by the U.S. Geological Survey in the use of these data.

  4. How can I download or order the data?


Who wrote the metadata?

Dates:
Last modified: 22-Jun-2006
Metadata author:
U.S. Geological Survey
c/o Charles A. Bush
MS 913, Box 25046, Room 1512, Building 25, Denver Federal Center
Lakewood, CO 80025
USA

303-236-4723 (voice)
303-236-0214 (FAX)
cbush@usgs.gov

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



 


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