Geologic map of the Tok River area, Tanacross A-5 and A-6 quadrangles, eastern Alaska Range, Alaska

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

Frequently anticipated questions:


What does this data set describe?

Title:
Geologic map of the Tok River area, Tanacross A-5 and A-6 quadrangles, eastern Alaska Range, Alaska
Abstract:
This 1:63,360 scale, geologic map describes the distribution bedrock units and surficial deposits in the Tok River area, Tanacross A-5 and A-6 quadrangles, eastern Alaska Range, Alaska. The Tok River geologic mapping project is part of a multi-year effort focusing on improving the publicly-available geological and geochemical data and assessing the mineral potential of the Tanacross quadrangle. The project focused on detailed mapping, identification, sampling and characterization of Devonian-Mississippian metamorphic rocks, Triassic and Cretaceous intrusions, and surficial geology, as well as modern geochemical characterizations of skarn, vein, and volcanogenic massive sulfide (VMS) hosted mineralization. The DGGS Mineral Resources section spent 321 person-days in the field in 2015 and 2016 to conduct approximately 540 square miles of 1:63,360-scale geologic mapping and sampling in the Tok River area, of central Alaska. The new geologic map will greatly improve the understanding of the geology, structural history, and mineral potential of the area (Sicard and others, in press). This area includes exposures of Devonian-Mississippian metamorphic rocks, metamorphosed Triassic gabbroic intrusions, and Cretaceous granodiorite intrusions and basaltic andesite lava flows. The area lies between the Delta mineral belt to the west, which has been the focus of exploration into VMS, and skarn deposits of the Tetlin project to the east. The area also contains numerous inactive and possibly active faults and multiple stages of deformation and magmatism, which are critical for understanding the geologic history of the eastern Alaska Range.
Supplemental_Information:
This digital data distribution package provides shapefiles and geodatabase that portray features presented in PIR 2017-3. Field names and values are organized according to the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP). This metadata file lists the table names and field names used in the geodatabase. Table and field names in the shapefiles are truncated at 10 characters. The geodatabase and selected shapefiles provide the following features:
Basemap: Geodatabase feature dataset that provides topographic contours, hydrology, and geographic place names 
CorrelationOfMapUnits: Geodatabase feature dataset that depicts the map unit correlation chart; includes applicable unit designators, brackets, dividing lines, and text 
CartographicLines: Cross section transects. 
ContactsAndFaults: Line features that depict faults and geologic contacts. 
DataSourcePolys: Polygons that delineate the data sources for various parts of the map. 
DataSources: Non-spatial reference table that provides bibliographic references for the datasets or information used to generate or interpret geologic or geographic features. 
DescriptionOfMapUnits: Non-spatial reference table that provides key information about each map unit. This table provides full unit descriptions. Additional information may be found in an accompanying report. 
GeochronPoints: Geochronology sample location points and symbology. 
GeologicLines: Dikes, coal seams, ash beds, glacial features, anticline and syncline hinge-surface traces, and other kinds of key beds that do not participate in map-unit topology. 
MapUnitPoints: A point file that provides locations and labels for key geologic features or observations. 
MapUnitPolys: Polygons that record the distribution of mapped or interpreted geologic units 
OtherPolys: Polygons that record the location and extent of geologic or geographic features other than the geologic units 
OrientationPoints: A point files that provide field station locations, symbology, and associated structure data (bedding attitudes, foliation attitudes, slip vectors measured at a point, etc.), NCGMP09 format. 
Stations: Field observation locations and descriptions
  1. How should this data set be cited?

    Sicard, K.R., Naibert, T.J., Hubbard, T.D., Twelker, Evan, Wypych, Alicja, Werdon, M.B., Willingham, A.L., Gillis, R.J., Lande, L.L., and Newberry, R.J., 2017, Geologic map of the Tok River area, Tanacross A-5 and A-6 quadrangles, eastern Alaska Range, Alaska: Preliminary Interpretive Report PIR 2017-3, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 15 p., 1 sheet, scale 1:63,360

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -144.705580
    East_Bounding_Coordinate: -142.470076
    North_Bounding_Coordinate: 63.514223
    South_Bounding_Coordinate: 62.559972

  3. What does it look like?

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

    Beginning_Date: 2015
    Ending_Date: 2017
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: report and 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: 7
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -141
      Latitude_of_Projection_Origin: 0
      False_Easting: 500000.000000
      False_Northing: 0

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.0001
      Ordinates (y-coordinates) are specified to the nearest 0.0001
      Planar coordinates are specified in Meters

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is GRS 80.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257222101000025.

  7. How does the data set describe geographic features?

    Basemap
    Geodatabase feature dataset that provides topographic contours, hydrology, and geographic place names (Source: Alaska Division of Geological & Geophysical Surveys (DGGS).This table is organized according to the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    CorrelationOfMapUnits
    Geodatabase feature dataset that depicts the map unit correlation chart; includes applicable unit designators, brackets, dividing lines, and text (Source: Alaska Division of Geological & Geophysical Surveys (DGGS).This table is organized according to the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    CartographicLines, CartographicLinesAnno
    Cross section transects. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS).This table is organized according to the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    Type
    Type values specify the kind of features represented by a line, point, or polygon (Source: Alaska Division of Geological & Geophysical Surveys)

    Feature type(s): Cross Section

    Symbol
    References the symbol value that was assigned to the point. (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:FGDC Digital Cartographic Standard for Geologic Map Symbolization; Appendix A. Geologic map symbols, colors, and patterns, "REF NO" field
    Codeset Source:Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates.

    Label
    The label values provide text strings to display along with their associated feature. Depending on the context of the feature class, label values will contain applicable FGDCGeoAge font characters, feature labels, dip and plunge values for measured orientations, or other special characters. (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:FGDCGeoAge font
    Codeset Source:Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates.

    DataSourceID
    Provides information about the source of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    Foreign key to the DataSources_ID field in the DataSources table.

    Notes
    Free text for additional information about a feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    The notes indicate the source of the feature interpretation or provide more information about the processing or data acquisition procedure.

    ContactsAndFaults, ContactsAndFaultsAnno
    Line features that depict faults and geologic contacts. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS).This table is organized according to the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    Type
    Type values specify the kind of features represented by a line, point, or polygon (Source: Alaska Division of Geological & Geophysical Surveys)

    Feature type(s): Map Boundary; Contact; Fault; Fault ; Lake Boundary

    IsConcealed
    This is a flag to identify contacts and faults covered by overlying map units. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    NThe feature IS NOT covered by an overlying map unit.
    YThe feature IS covered by an overlying map unit.

    ExistenceConfidence
    Indicates the degree of confidence and/or certainty in the interpretation of a a feature's existence. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    certainIndicates that the author has sufficient observational and/or other supporting data to be reasonably confident in the scientific credibility of the interpretation of the feature. The level of certainty is specific to the map scale.
    questionableThe interpretation of the feature at the mapped scale fits the overall proposed geologic model but the extent and/or classification is questionable or uncertain due to insufficient observations and/or supporting data.

    IdentityConfidence
    Indicates degree of confidence in the identification and classification of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    certainIndicates that the author has sufficient observational and/or other supporting data to be reasonably confident in the scientific credibility of the interpretation of the feature. The level of certainty is specific to the map scale.
    questionableThe interpretation of the feature at the mapped scale fits the overall proposed geologic model but the extent and/or classification is questionable or uncertain due to insufficient observations and/or supporting data.

    LocationConfidenceMeters
    Half-width in meters of positional uncertainty envelope; position is relative to other features in the data. A value of -9 indicates that this measure is not available. (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0
    Maximum:250
    Units:meters

    Symbol
    References the symbol value that was assigned to the point. (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:FGDC Digital Cartographic Standard for Geologic Map Symbolization; Appendix A. Geologic map symbols, colors, and patterns, "REF NO" field
    Codeset Source:Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates.

    Label
    The label values provide text strings to display along with their associated feature. Depending on the context of the feature class, label values will contain applicable FGDCGeoAge font characters, feature labels, dip and plunge values for measured orientations, or other special characters. (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:FGDCGeoAge font
    Codeset Source:Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates.

    DataSourceID
    Provides information about the source of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    Foreign key to the DataSources_ID field in the DataSources table.

    Notes
    Free text for additional information about a feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    The notes indicate the source of the feature interpretation or provide more information about the processing or data acquisition procedure.

    DataSourcePolys, DataSourcePolysAnno
    Polygons that delineate the data sources for various parts of the map. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS).This table is organized according to the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    Notes
    Free text for additional information about a feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    The notes indicate the source of the feature interpretation or provide more information about the processing or data acquisition procedure.

    DataSourceID
    Provides information about the source of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    Foreign key to the DataSources_ID field in the DataSources table.

    Label
    The label values provide text strings to display along with their associated feature. Depending on the context of the feature class, label values will contain applicable FGDCGeoAge font characters, feature labels, dip and plunge values for measured orientations, or other special characters. (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:FGDCGeoAge font
    Codeset Source:Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates.

    DataSources
    Non-spatial reference table that provides bibliographic references for the datasets or information used to generate or interpret geologic or geographic features. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS).This table is organized according to the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    DataSources_ID
    Provides information about the source of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    Primary key in the DataSources table; Example values = DAS1, DAS2, DAS3,... Null values not permitted

    Source
    Plain-text short description that identifies the data source. (Source: Alaska Division of Geological & Geophysical Surveys)

    By convention, for DataSources_ID = DAS1, Source = 'This report'. Other values are standard bibliographic references. Null values not permitted.

    Notes
    Free text for additional information about a feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    The notes indicate the source of the feature interpretation or provide more information about the processing or data acquisition procedure.

    DescriptionOfMapUnits
    Non-spatial reference table that provides key information about each map unit. This table provides full unit descriptions. Additional information may be found in an accompanying report. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS).This table is organized according to the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    MapUnit
    Short ASCII string that indicates the map unit. Note: map units in parentheses, such as (Qcf), indicate combined map units consisting of bedrock overlain by thin or discontinuous deposits of the map unit. Map units with a question mark, such as (Qus?), indicate an uncertain identification. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    DagGranitic augen orthogneiss
    DfsFelsic Metavolcanic Schist
    DgGneiss and schist
    DlLagoon Unit schist
    KJgnGravina-Nutzotin Belt
    KqdQuartz diorite
    MDcsQuartzite and quartz schist
    MDdFelsic metavolcanic schist
    MDgsMafic metavolcanic schist with quartz schist and minor felsic metavolcanics
    MDmsQuartzite and quartz schist with calcareous schist and marble
    MDpGraphite-bearing quartz schist with lesser metavolcanic schist
    MDqDrum Unit felsic schist
    QaUndifferentiated floodplain alluvium
    QaaActive-floodplain alluvium
    QabAbandoned-floodplain alluvium
    QafAlluvial-fan deposits
    QaiInactive-floodplain alluvium
    QatAlluvial-terrace deposits
    QcUndifferentiated colluvium
    QcfMixed colluvium and alluvium
    QcgRock glacier deposits
    QclLandslide deposits
    QctTalus and blockfield deposits
    QfbFlood-bar deposits
    Qgd1Drift of early Wisconsinan age
    Qgd2Drift of late Wisconsinan age
    Qgf2Outwash deposits of late Wisconsinan age
    QglGlacially impounded lake deposits of late Wisconsinan age
    TRgPhyllite, metaconglomerate and marble
    TcBasaltic andesite to andesite flows
    lKbaGranodiorite and granodiorite porphyry
    lKgdMetagabbro

    Name
    Full map unit name, identifies the unit within its hierarchical context. (Source: Alaska Division of Geological & Geophysical Surveys)

    When applicable, usage is consistent with U.S. Geologic Names Lexicon

    Age
    Stratigraphic ranges or age of the map unit. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    NULLnot applicable

    Formal codeset
    Codeset Name:Geologic Time Scale v. 4.0
    Codeset Source:Walker, J.D., Geissman, J.W., Bowring, S.A, and Babcock, L.E., comp., 2012, Geologic Time Scale v. 4.0: Geological Society of America

    Description
    Free-format text description of the map unit. (Source: Alaska Division of Geological & Geophysical Surveys)

    Commonly structured according to one or more accepted traditions (for example, lithology, thickness, color, weathering and outcrop characteristics, distinguishing features, genesis, age constraints).

    GeochronPoints, GeochronPointsAnno, GeochronPointsAnnoMask
    Geochronology sample location points and symbology. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS).This table is organized according to the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    Type
    Type values specify the kind of features represented by a line, point, or polygon (Source: Alaska Division of Geological & Geophysical Surveys)

    Feature type(s): Ar-Ar; DZ; U-Pb

    StationID
    Identifier assigned by person who originally located station (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    NULLA station number was not recorded or was not assigned.

    This field mapping program used a station numbering convention that differers from the DGGS standard station numbering format.

    MapUnit
    Short ASCII string that indicates the map unit. Note: map units in parentheses, such as (Qcf), indicate combined map units consisting of bedrock overlain by thin or discontinuous deposits of the map unit. Map units with a question mark, such as (Qus?), indicate an uncertain identification. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    DagGranitic augen orthogneiss
    DgGneiss and schist
    MDqDrum Unit felsic schist
    lKbaGranodiorite and granodiorite porphyry
    lKgdMetagabbro

    Symbol
    References the symbol value that was assigned to the point. (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:FGDC Digital Cartographic Standard for Geologic Map Symbolization; Appendix A. Geologic map symbols, colors, and patterns, "REF NO" field
    Codeset Source:Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates.

    Label
    The label values provide text strings to display along with their associated feature. Depending on the context of the feature class, label values will contain applicable FGDCGeoAge font characters, feature labels, dip and plunge values for measured orientations, or other special characters. (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:FGDCGeoAge font
    Codeset Source:Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates.

    MaterialAnalyzed
    Type of material used for analysis. (Source: Alaska Division of Geological & Geophysical Surveys)

    Material type(s): biotite; sericite; hornblende; whole rock; zircon; muscovite

    LocationConfidenceMeters
    Half-width in meters of positional uncertainty envelope; position is relative to other features in the data. A value of -9 indicates that this measure is not available. (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:10
    Maximum:10
    Units:meters

    Age
    The interpreted (preferred) age calculated from geochronological analysis. Note: units provided in AgeUnits field. (Source: Volcano Science Center geochronology lab, U.S. Geological Survey, Menlo Park, California)

    Range of values
    Minimum:0
    Maximum:366

    AgePlusError
    The upper age plus error calculated from geochronological analysis. Note: units provided in AgeUnits field. (Source: Volcano Science Center geochronology lab, U.S. Geological Survey, Menlo Park, California)

    Range of values
    Minimum:0
    Maximum:3

    AgeMinusError
    The lower age plus error calculated from geochronological analysis. Note: units provided in AgeUnits field. (Source: Volcano Science Center geochronology lab, U.S. Geological Survey, Menlo Park, California)

    Range of values
    Minimum:0
    Maximum:3

    AgeUnits
    Units of the geochronology analysis. (Source: Alaska Division of Geological & Geophysical Surveys or originating reference)

    Units(s): Ma

    LocationSourceID
    Provides information about the source of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    Foreign key to the DataSources_ID field in the DataSources table.

    Notes
    Free text for additional information about a feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    The notes indicate the source of the feature interpretation or provide more information about the processing or data acquisition procedure.

    GeologicLines
    Dikes, coal seams, ash beds, glacial features, anticline and syncline hinge-surface traces, and other kinds of key beds that do not participate in map-unit topology. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS).This table is organized according to the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    Type
    Type values specify the kind of features represented by a line, point, or polygon (Source: Alaska Division of Geological & Geophysical Surveys)

    Feature type(s): Trachyandesitic dike; Gabbro dike; Basaltic-Andesite dike; Antiform

    IsConcealed
    This is a flag to identify contacts and faults covered by overlying map units. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    NThe feature IS NOT covered by an overlying map unit.

    ExistenceConfidence
    Indicates the degree of confidence and/or certainty in the interpretation of a a feature's existence. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    certainIndicates that the author has sufficient observational and/or other supporting data to be reasonably confident in the scientific credibility of the interpretation of the feature. The level of certainty is specific to the map scale.
    questionableThe interpretation of the feature at the mapped scale fits the overall proposed geologic model but the extent and/or classification is questionable or uncertain due to insufficient observations and/or supporting data.

    IdentityConfidence
    Indicates degree of confidence in the identification and classification of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    certainIndicates that the author has sufficient observational and/or other supporting data to be reasonably confident in the scientific credibility of the interpretation of the feature. The level of certainty is specific to the map scale.
    questionableThe interpretation of the feature at the mapped scale fits the overall proposed geologic model but the extent and/or classification is questionable or uncertain due to insufficient observations and/or supporting data.

    LocationConfidenceMeters
    Half-width in meters of positional uncertainty envelope; position is relative to other features in the data. A value of -9 indicates that this measure is not available. (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:25
    Maximum:250
    Units:meters

    Symbol
    References the symbol value that was assigned to the point. (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:FGDC Digital Cartographic Standard for Geologic Map Symbolization; Appendix A. Geologic map symbols, colors, and patterns, "REF NO" field
    Codeset Source:Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates.

    DataSourceID
    Provides information about the source of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    Foreign key to the DataSources_ID field in the DataSources table.

    MapUnitPoints
    A point file that provides locations and labels for key geologic features or observations. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS).This table is organized according to the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    MapUnit
    Short ASCII string that indicates the map unit. Note: map units in parentheses, such as (Qcf), indicate combined map units consisting of bedrock overlain by thin or discontinuous deposits of the map unit. Map units with a question mark, such as (Qus?), indicate an uncertain identification. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    DgGneiss and schist
    MDcsQuartzite and quartz schist
    MDgsMafic metavolcanic schist with quartz schist and minor felsic metavolcanics
    MDmsQuartzite and quartz schist with calcareous schist and marble
    MDqDrum Unit felsic schist
    Qgd1Drift of early Wisconsinan age
    Qgd2Drift of late Wisconsinan age
    TRgPhyllite, metaconglomerate and marble

    IdentityConfidence
    Indicates degree of confidence in the identification and classification of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    certainIndicates that the author has sufficient observational and/or other supporting data to be reasonably confident in the scientific credibility of the interpretation of the feature. The level of certainty is specific to the map scale.

    Label
    The label values provide text strings to display along with their associated feature. Depending on the context of the feature class, label values will contain applicable FGDCGeoAge font characters, feature labels, dip and plunge values for measured orientations, or other special characters. (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:FGDCGeoAge font
    Codeset Source:Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates.

    Symbol
    References the symbol value that was assigned to the point. (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:FGDC Digital Cartographic Standard for Geologic Map Symbolization; Appendix A. Geologic map symbols, colors, and patterns, "REF NO" field
    Codeset Source:Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates.

    Notes
    Free text for additional information about a feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    The notes indicate the source of the feature interpretation or provide more information about the processing or data acquisition procedure.

    DataSourceID
    Provides information about the source of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    Foreign key to the DataSources_ID field in the DataSources table.

    Type
    Type values specify the kind of features represented by a line, point, or polygon (Source: Alaska Division of Geological & Geophysical Surveys)

    Feature type(s): calc-schist; marble; Garnet; Graphite-bearing

    MapUnitPolys, MapUnitPolysAnno, MapUnitPolysAnnoMask
    Polygons that record the distribution of mapped or interpreted geologic units (Source: Alaska Division of Geological & Geophysical Surveys (DGGS)This table is organized according to the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    MapUnit
    Short ASCII string that indicates the map unit. Note: map units in parentheses, such as (Qcf), indicate combined map units consisting of bedrock overlain by thin or discontinuous deposits of the map unit. Map units with a question mark, such as (Qus?), indicate an uncertain identification. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    DagGranitic augen orthogneiss
    DgGneiss and schist
    DlLagoon Unit schist
    KJgnGravina-Nutzotin Belt
    KqdQuartz diorite
    MDcsQuartzite and quartz schist
    MDdFelsic metavolcanic schist
    MDgsMafic metavolcanic schist with quartz schist and minor felsic metavolcanics
    MDmsQuartzite and quartz schist with calcareous schist and marble
    MDqDrum Unit felsic schist
    QaUndifferentiated floodplain alluvium
    QaaActive-floodplain alluvium
    QabAbandoned-floodplain alluvium
    QafAlluvial-fan deposits
    QaiInactive-floodplain alluvium
    QatAlluvial-terrace deposits
    QcUndifferentiated colluvium
    QcfMixed colluvium and alluvium
    QcgRock glacier deposits
    QclLandslide deposits
    QctTalus and blockfield deposits
    QfbFlood-bar deposits
    Qgd1Drift of early Wisconsinan age
    Qgd2Drift of late Wisconsinan age
    Qgf2Outwash deposits of late Wisconsinan age
    QglGlacially impounded lake deposits of late Wisconsinan age
    TRgPhyllite, metaconglomerate and marble
    TcBasaltic andesite to andesite flows
    lKbaGranodiorite and granodiorite porphyry
    lKgdMetagabbro

    IdentityConfidence
    Indicates degree of confidence in the identification and classification of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    certainIndicates that the author has sufficient observational and/or other supporting data to be reasonably confident in the scientific credibility of the interpretation of the feature. The level of certainty is specific to the map scale.
    questionableThe interpretation of the feature at the mapped scale fits the overall proposed geologic model but the extent and/or classification is questionable or uncertain due to insufficient observations and/or supporting data.
    unspecifiedThe author has not specified a level of confidence or certainty in the interpretation of the feature.

    Label
    The label values provide text strings to display along with their associated feature. Depending on the context of the feature class, label values will contain applicable FGDCGeoAge font characters, feature labels, dip and plunge values for measured orientations, or other special characters. (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:FGDCGeoAge font
    Codeset Source:Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates.

    Symbol
    References the CMYK color value that was assigned to the map unit. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    X2X0CMYK value - C:100%, M:20%, Y:100%, K:0%
    7500CMYK value - C:70%, M:50%, Y:0%, K:0%
    0400CMYK value - C:0%, M:40%, Y:0%, K:0%
    22A0CMYK value - C:20%, M:20%, Y:8%, K:0%
    AX60CMYK value - C:8%, M:100%, Y:60%, K:0%
    3520CMYK value - C:30%, M:50%, Y:20%, K:0%
    25X0CMYK value - C:20%, M:50%, Y:100%, K:0%
    5630CMYK value - C:50%, M:60%, Y:30%, K:0%
    X100CMYK value - C:100%, M:13%, Y:0%, K:0%
    5720CMYK value - C:50%, M:70%, Y:20%, K:0%
    0060CMYK value - C:0%, M:0%, Y:60%, K:0%
    0AX0CMYK value - C:0%, M:8%, Y:100%, K:0%
    A260CMYK value - C:8%, M:20%, Y:60%, K:0%
    0370CMYK value - C:0%, M:30%, Y:70%, K:0%
    02X0CMYK value - C:0%, M:20%, Y:100%, K:0%
    0250CMYK value - C:0%, M:20%, Y:50%, K:0%
    0A50CMYK value - C:0%, M:8%, Y:50%, K:0%
    0020CMYK value - C:0%, M:0%, Y:20%, K:0%
    A330CMYK value - C:8%, M:30%, Y:30%, K:0%
    00X0CMYK value - C:0%, M:0%, Y:100%, K:0%
    0040CMYK value - C:0%, M:0%, Y:40%, K:0%
    A360CMYK value - C:8%, M:30%, Y:60%, K:0%
    0170CMYK value - C:0%, M:13%, Y:70%, K:0%
    0560CMYK value - C:0%, M:50%, Y:60%, K:0%
    A340CMYK value - C:8%, M:30%, Y:40%, K:0%
    2000CMYK value - C:20%, M:0%, Y:0%, K:0%
    42A0CMYK value - C:40%, M:20%, Y:8%, K:0%
    2350CMYK value - C:20%, M:30%, Y:50%, K:0%
    6420CMYK value - C:60%, M:40%, Y:20%, K:0%
    07X0CMYK value - C:0%, M:70%, Y:100%, K:0%
    6540CMYK value - C:60%, M:50%, Y:40%, K:0%
    0X20CMYK value - C:0%, M:100%, Y:20%, K:0%
    30X0CMYK value - C:30%, M:0%, Y:100%, K:0%

    Notes
    Free text for additional information about a feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    The notes indicate the source of the feature interpretation or provide more information about the processing or data acquisition procedure.

    DataSourceID
    Provides information about the source of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    Foreign key to the DataSources_ID field in the DataSources table.

    OtherPolys
    Polygons that record the location and extent of geologic or geographic features other than the geologic units (Source: Alaska Division of Geological & Geophysical Surveys (DGGS)This table is organized according to the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    Type
    Type values specify the kind of features represented by a line, point, or polygon (Source: Alaska Division of Geological & Geophysical Surveys)

    Feature type(s): Conductive area in 900 Hz EM survey; Geologic unit pattern for Qgd1; Geologic unit pattern for Qgd2; Bedrock thinly covered by Qgd1; Bedrock thinly covered by Qgd2; Map Neatline; Tetlin Land

    IdentityConfidence
    Indicates degree of confidence in the identification and classification of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    certainIndicates that the author has sufficient observational and/or other supporting data to be reasonably confident in the scientific credibility of the interpretation of the feature. The level of certainty is specific to the map scale.
    questionableThe interpretation of the feature at the mapped scale fits the overall proposed geologic model but the extent and/or classification is questionable or uncertain due to insufficient observations and/or supporting data.

    Symbol
    References the symbol value that was assigned to the point. (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:FGDC Digital Cartographic Standard for Geologic Map Symbolization; Appendix A. Geologic map symbols, colors, and patterns, "REF NO" field
    Codeset Source:Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates.

    Label
    The label values provide text strings to display along with their associated feature. Depending on the context of the feature class, label values will contain applicable FGDCGeoAge font characters, feature labels, dip and plunge values for measured orientations, or other special characters. (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:FGDCGeoAge font
    Codeset Source:Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates.

    Notes
    Free text for additional information about a feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    The notes indicate the source of the feature interpretation or provide more information about the processing or data acquisition procedure.

    DataSourceID
    Provides information about the source of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    Foreign key to the DataSources_ID field in the DataSources table.

    OrientationPoints, OrientationPointsAnno, OrientationPointsAnnoMask, OrientationPointsMask
    A point files that provide field station locations, symbology, and associated structure data (bedding attitudes, foliation attitudes, slip vectors measured at a point, etc.), NCGMP09 format. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS)This table is organized according to the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    Type
    Type values specify the kind of features represented by a line, point, or polygon (Source: Alaska Division of Geological & Geophysical Surveys)

    Feature type(s): schistosity; foliation; cleavage; bedding; bed parallel schistosity; compaction foliation; compositional layering; gneissic layering; bedding from photo; crenulation; fold axis; crenulation lineation; stretched mineral; mineral lineation; stretching lineation; intersection lineation; stretched pebble; slickenline; hinge line; intermediate-felsic dike; generic dike; gabbro dike; biotite dike

    StationID
    Identifier assigned by person who originally located station (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    NULLA station number was not recorded or was not assigned.

    This field mapping program used a station numbering convention that differers from the DGGS standard station numbering format.

    MapUnit
    Short ASCII string that indicates the map unit. Note: map units in parentheses, such as (Qcf), indicate combined map units consisting of bedrock overlain by thin or discontinuous deposits of the map unit. Map units with a question mark, such as (Qus?), indicate an uncertain identification. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    DagGranitic augen orthogneiss
    DgGneiss and schist
    DlLagoon Unit schist
    MDcsQuartzite and quartz schist
    MDdFelsic metavolcanic schist
    MDgsMafic metavolcanic schist with quartz schist and minor felsic metavolcanics
    MDmsQuartzite and quartz schist with calcareous schist and marble
    MDqDrum Unit felsic schist
    QcUndifferentiated colluvium
    QcfMixed colluvium and alluvium
    Qgd1Drift of early Wisconsinan age
    Qgd2Drift of late Wisconsinan age
    TRgPhyllite, metaconglomerate and marble

    Symbol
    References the symbol value that was assigned to the point. (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:FGDC Digital Cartographic Standard for Geologic Map Symbolization; Appendix A. Geologic map symbols, colors, and patterns, "REF NO" field
    Codeset Source:Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates.

    Label
    The label values provide text strings to display along with their associated feature. Depending on the context of the feature class, label values will contain applicable FGDCGeoAge font characters, feature labels, dip and plunge values for measured orientations, or other special characters. (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:FGDCGeoAge font
    Codeset Source:Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates.

    LocationConfidenceMeters
    Half-width in meters of positional uncertainty envelope; position is relative to other features in the data. A value of -9 indicates that this measure is not available. (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:10
    Maximum:50
    Units:meters

    Azimuth
    Strike or trend, measured in degrees clockwise from geographic North, using right-hand rule (dip is to right of azimuth direction). Note: Null values not permitted according to the NCGMP09 standard; zero values may indicate that the orientation of the feature was not measured. (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0
    Maximum:358
    Units:degrees

    Inclination
    Dip or plunge, measured in degrees down from horizontal. Note: Null values not permitted according to the NCGMP09 standard; zero values may indicate that the orientation of the feature was not measured. (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0
    Maximum:90
    Units:degrees

    IdentityConfidence
    Indicates degree of confidence in the identification and classification of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    certainIndicates that the author has sufficient observational and/or other supporting data to be reasonably confident in the scientific credibility of the interpretation of the feature. The level of certainty is specific to the map scale.

    OrientationConfidenceDegrees
    Estimated circular error, in degrees. For planar features, error in orientation of pole to plane. Note: Null values not permitted according to the NCGMP09 standard; zero values may indicate that the orientation of the feature was not measured. (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:5
    Maximum:10
    Units:degrees

    LocationSourceID
    Provides information about the source of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    Foreign key to the DataSources_ID field in the DataSources table.

    DataSourceID
    Provides information about the source of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    Foreign key to the DataSources_ID field in the DataSources table.

    Notes
    Free text for additional information about a feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    The notes indicate the source of the feature interpretation or provide more information about the processing or data acquisition procedure.

    Stations, StationsAnno
    Field observation locations and descriptions (Source: Alaska Division of Geological & Geophysical Surveys (DGGS).This table is organized according to the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    FieldID
    Identifier assigned by person who originally located station (Source: Alaska Division of Geological & Geophysical Surveys)

    Generic example of a sample identifier: YYYYAAA9999X; YY or YYYY= year, AAA=geologist's initials (one to three characters), 9999=unique station number, X= optional alpha character which indicates that multiple samples were collected at a given location or that multiple observations were recorded in the project database.

    MapUnit
    Short ASCII string that indicates the map unit. Note: map units in parentheses, such as (Qcf), indicate combined map units consisting of bedrock overlain by thin or discontinuous deposits of the map unit. Map units with a question mark, such as (Qus?), indicate an uncertain identification. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    NULLBlank (NULL) field values indicate that a map unit value was not assigned.
    DagGranitic augen orthogneiss
    DgGneiss and schist
    DlLagoon Unit schist
    KqdQuartz diorite
    MDcsQuartzite and quartz schist
    MDgsMafic metavolcanic schist with quartz schist and minor felsic metavolcanics
    MDmsQuartzite and quartz schist with calcareous schist and marble
    MDqDrum Unit felsic schist
    QaUndifferentiated floodplain alluvium
    QaaActive-floodplain alluvium
    QafAlluvial-fan deposits
    QatAlluvial-terrace deposits
    QcUndifferentiated colluvium
    QcfMixed colluvium and alluvium
    QcgRock glacier deposits
    QclLandslide deposits
    QfbFlood-bar deposits
    Qgd1Drift of early Wisconsinan age
    Qgd2Drift of late Wisconsinan age
    Qgf2Outwash deposits of late Wisconsinan age
    TRgPhyllite, metaconglomerate and marble
    TcBasaltic andesite to andesite flows
    lKbaGranodiorite and granodiorite porphyry
    lKgdMetagabbro

    Symbol
    References the symbol value that was assigned to the point. (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:FGDC Digital Cartographic Standard for Geologic Map Symbolization; Appendix A. Geologic map symbols, colors, and patterns, "REF NO" field
    Codeset Source:Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates.

    LocationConfidenceMeters
    Half-width in meters of positional uncertainty envelope; position is relative to other features in the data. A value of -9 indicates that this measure is not available. (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:10
    Maximum:10
    Units:meters

    LocationMethod
    Term that categorizes technique used to determine station location (Source: Alaska Division of Geological & Geophysical Surveys)

    Location method(s): handheld GPS

    Observer
    Name of the person who located station (Source: Alaska Division of Geological & Geophysical Surveys)

    Observer(s): Sicard, Karri; Twelker, Evan; Reioux, David; Lande, Lauren; Wypych, Alicja; Freeman, Larry; Willingham, Mandy; Dashevsky, Sam; Naibert, Travis; Werdon, Melanie; Gillis, Bob; Newberry, Rainer; Hubbard, Trent

    DataSourceID
    Provides information about the source of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    Foreign key to the DataSources_ID field in the DataSources table.

    Notes
    Free text for additional information about a feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    The notes indicate the source of the feature interpretation or provide more information about the processing or data acquisition procedure.

    GPSX
    Station coordinate downloaded from GPS, WGS84 datum. (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:-144.300013
    Maximum:-142.796965
    Units:degrees

    GPSY
    Station coordinate downloaded from GPS, WGS84 datum. (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:62.903738
    Maximum:63.32752
    Units:degrees


Who produced the data set?

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

  2. Who also contributed to the data set?

    This project is jointly funded by the State of Alaska's Strategic and Critical Minerals Assessment project (part of DGGS's Airborne Geophysical/Geological Mineral Inventory program [AGGMI]), a USGS Mineral Resources Assessment Grant G16AS00003, and the USGS National Cooperative Geologic Mapping Program, STATEMAP component, under award number G16AC00182 for 2016. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government. We acknowledge Heidi Lingenfelter and Joe Bovee representing Ahtna, Inc., James Mery of Doyon Limited, and Mentasta Village, for providing access to private lands in the map area. U.S. Bureau of Land Management (BLM) Glennallen Field Office and Tom Beaucage of (BLM) Eastern Field Office (Fairbanks) assisted us with permitting on BLM-managed lands. We thank Lawrence K. Freeman, James V. Jones III, Erin Todd, Samuel Dashevsky, Peter Illig, and others for enlightening geological discussions. Lawrence Freeman and David Reioux participated in 2015 field work. Jeff Benowitz and Paul Layer of the University of Alaska Fairbanks Geochronology Lab conducted the 40Ar/39Ar analyses and assisted us in their interpretation. Dick Reger and Jennifer Athey gave timely and constructive technical reviews. We appreciate the warm hospitality and logistical support of John and Jill Rusyniak of Log Cabin Wilderness Lodge, and we thank Soloy Helicopters LLC pilots Sam Gawaith and Frank Ross for skilled and safe flying.

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

    Alaska Division of Geological & Geophysical Surveys
    Metadata Manager
    3354 College Road
    Fairbanks, AK 99709-3707
    USA

    (907)451-5020 (voice)
    (907)451-5050 (FAX)
    dggspubs@alaska.gov

    Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays


Why was the data set created?

The Tok River geologic mapping project is part of a multi-year effort focusing on improving the publicly-available geological and geochemical data and assessing the mineral potential of the Tanacross quadrangle. The project focused on detailed mapping, identification, sampling and characterization of Devonian-Mississippian metamorphic rocks, Triassic and Cretaceous intrusions, and surficial geology, as well as modern geochemical characterizations of skarn, vein, and volcanogenic massive sulfide (VMS) hosted mineralization. The area lies between the Delta mineral belt to the west, which has been the focus of exploration into VMS, and skarn deposits of the Tetlin project to the east. The area also contains numerous inactive and possibly active faults and multiple stages of deformation and magmatism, which are critical for understanding the geologic history of the eastern Alaska Range.


How was the data set created?

  1. From what previous works were the data drawn?

    Dashevsky, S.S. and others, 2003 (source 1 of 8)
    Dashevsky, S.S., Schaefer, C.F., and Hunter, E.N., 2003, Bedrock geologic map of the Delta mineral belt, Tok mining district, Alaska: Professional Report PR 122, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 122 p., 2 sheets, scale 1:63,360
    Type_of_Source_Media: paper
    Source_Scale_Denominator: 63360
    Source_Contribution: geologic mapping

    Emond, A.M. and others, 2015 (source 2 of 8)
    Emond, A.M., CGG, Burns, L.E., Graham, G.R.C., and (US), CGG Land Inc., 2015, Tok electromagnetic and magnetic airborne geophysical survey data compilation: Geophysical Report GPR 2015-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Type_of_Source_Media: digital data
    Source_Contribution: geologic mapping

    Foster, H.L., 1970 (source 3 of 8)
    Foster, H.L., 1970, Reconnaissance geologic map of the Tanacross Quadrangle, Alaska: Miscellaneous Geologic Investigations Map I 593, U.S. Geological Survey, United States.

    Online Links:

    Other_Citation_Details: 1 sheet, scale 1:250,000
    Type_of_Source_Media: paper
    Source_Scale_Denominator: 250000
    Source_Contribution: geologic mapping

    Naibert, T.J. and others, 2016 (source 4 of 8)
    Naibert, T.J., Werdon, M.B., Lande, Lauren, and Wypych, Alicja, 2016, Trace-element geochemical data from stream sediments collected in the Tok River area, Tanacross A-5 and A-6 quadrangles, Alaska in 2016: Raw Data File RDF 2016-10, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 3 p
    Type_of_Source_Media: digital data
    Source_Contribution: geologic mapping

    Nokleberg, W.J. and others, 2015 (source 5 of 8)
    Nokleberg, W.J., Aleinikoff, J.N., Bond, G.C., Ferrians, O.J., Jr., Herzon, P.L., Lange, I.M., Miyaoka, R.T., Richter, D.H., Schwab, C.E., Silva, S.R., Smith, T.E., and Zehner, R.E., 2015, Geologic maps of the eastern Alaska Range, Alaska (44 quadrangles, 1:63,360 scale), with descriptions and interpretations of map units: Report of Investigation RI 2015-6, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 64 p., 45 sheets, scale 1:63,360
    Type_of_Source_Media: paper
    Source_Scale_Denominator: 63360
    Source_Contribution: geologic mapping

    Richter, D.H., 1976 (source 6 of 8)
    Richter, D.H., 1976, Geologic map of the Nabesna Quadrangle, Alaska: Miscellaneous Investigations Series Map I 932, U.S. Geological Survey, United States.

    Online Links:

    Other_Citation_Details: 1 sheet, scale 1:250,000
    Type_of_Source_Media: paper
    Source_Scale_Denominator: 250000
    Source_Contribution: geologic mapping

    Wilson, F.H. and others, 2015 (source 7 of 8)
    Wilson, F.H., Hults, C.P., Mull, C.G., and Karl, S.M., 2015, Geologic map of Alaska: Scientific Investigations Map SIM 3340, U.S. Geological Survey, United States.

    Online Links:

    Other_Citation_Details: 197 p., 2 sheets, scale 1:1,584,000
    Type_of_Source_Media: digital data
    Source_Scale_Denominator: 1584000
    Source_Contribution: geologic mapping

    Wypych, Alicja and others, 2016 (source 8 of 8)
    Wypych, Alicja, Sicard, K.R., Gillis, R.J., Lande, L.L., Naibert, T.J., Newberry, R.J., Twelker, Evan, Werdon, M.B., and Willingham, A.L., 2016, Major-oxide and trace-element geochemical data from rocks collected in the Tok River area, Tanacross A-5 and A-6 quadrangles, Alaska in 2016: Raw Data File RDF 2016-9, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 3 p
    Type_of_Source_Media: digital data
    Source_Contribution: geologic mapping

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

    Date: 2016 (process 1 of 4)
    Geologic mapping - The DGGS Mineral Resources section spent 321 person-days in the field in 2015 and 2016 to conduct approximately 540 square miles of 1:63,360-scale geologic mapping and sampling in the Tok River area. Field observations were integrated with geophysical surveys of the area and with existing literature. Geologists observed details about the variations in texture, lithology and orientation of the map units and collected rock samples, noted outcrop descriptions, and conducted structural measurements. Selected samples were submitted for geochronologic and geochemical analysis and the results were used to further interpret the stratigraphic and structural history of the map area. A complete list of references can be found in the accompanying report.

    Data sources used in this process:

    • Dashevsky, S.S. and others, 2003
    • Emond, A.M. and others, 2015
    • Foster, H.L., 1970
    • Naibert, T.J. and others, 2016
    • Nokleberg, W.J. and others, 2015
    • Richter, D.H., 1976
    • Wilson, F.H. and others, 2015
    • Wypych, Alicja and others, 2016

    Date: 2016 (process 2 of 4)
    GIS analysis and digital cartography - The geologic and geographic features portrayed in this data distribution package were attributed according to the NCGMP09 geodatabase standard.

    Date: 2016 (process 3 of 4)
    Technical review - This is a final report of scientific research. It has received technical review and editing by several scientists familiar with the subject matter. We incorporated the reviewers' suggestions into the final draft when deemed appropriate.

    Date: 2018 (process 4 of 4)
    Station and sample number editing - During final data organization and while attaching GPSX and GPSY coordinates, duplicate sample numbers in the STATIONS features were deleted if they were closer than 10 meters to each other. A number of stations had duplicate sample numbers and were further than 10 meters apart. In these cases, a decimal was added to the end of the sample number to distinguish them as different locations (i.e., added .1 or .2). In some cases, individual samples collected at a given station (outcrop) were erroneously assigned unique station numbers in the form of 16RN152A, 16RN152B. we corrected these station numbers to comply with DGGS 1:many station/sample numbering standards, example: 16RN152 (station number) and 16RN152A, 16RN152B (sample numbers).

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

    Benowitz, J.A., Sicard, K.R., Naibert, T.J., and Layer, P.W., 2017, 40Ar/39Ar data from the Tok River area, Tanacross A-5 and A-6 quadrangles and adjoining areas, eastern Alaska Range: Raw Data File RDF 2017-5, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 26 p
    Emond, A.M., CGG, Burns, L.E., Graham, G.R.C., and (US), CGG Land Inc., 2015, Tok electromagnetic and magnetic airborne geophysical survey data compilation: Geophysical Report GPR 2015-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Naibert, T.J., Werdon, M.B., Lande, Lauren, and Wypych, Alicja, 2016, Trace-element geochemical data from stream sediments collected in the Tok River area, Tanacross A-5 and A-6 quadrangles, Alaska in 2016: Raw Data File RDF 2016-10, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 3 p
    Twelker, Evan, Freeman, L.K., Sicard, K.R., and Busk, A.C., 2016, Preliminary report on mineral occurrences in the Tok River area, Alaska: Preliminary Interpretive Report PIR 2016-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 7 p
    Wypych, Alicja, Sicard, K.R., Gillis, R.J., Lande, L.L., Naibert, T.J., Newberry, R.J., Twelker, Evan, Werdon, M.B., and Willingham, A.L., 2016, Major-oxide and trace-element geochemical data from rocks collected in the Tok River area, Tanacross A-5 and A-6 quadrangles, Alaska in 2016: Raw Data File RDF 2016-9, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 3 p
    Wypych, Alicja, Sicard, K.R., Twelker, Evan, Freeman, L.K., Lande, Lauren, and Reioux, D.A., 2015, Major-oxide and trace-element geochemical data from rocks collected in 2015 in the Tok area, Tanacross A-5, A-6, and parts of adjacent quadrangles, Alaska: Raw Data File RDF 2015-15 v. 1.1, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 3 p


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

  1. How well have the observations been checked?

    Certainty in attribute interpretation varies throughout the map. Attribute fields within each table record the author's degree of confidence in the existence or identity of applicable features. This publication is a final report of research and has received two technical reviews as well as technical editing.

  2. How accurate are the geographic locations?

    Certainty in feature boundaries or location varies throughout the map. Data fields within each table record the author's degree of confidence in the location of applicable features. Station locations for orientation measurements and rock samples were collected (WGS84 datum) using Trimble Juno T41/5 WAAS-enabled GPS devices running ArcGIS for Windows Mobile. Map unit boundaries and structures were initially compiled in an ArcGIS geodatabase using UTM Zone 7, NAD27 base maps and aerial photography. The geodatabase was transformed to UTM Zone 7, NAD83 prior to publication. Comparison of the originating GPS station coordinates and the transformed coordinates indicates that the transformation introduced systematic 2-3 meter positional discrepancies. The Stations table provides the originating GPS latitude and longitude coordinates (WGS84) for all field stations, which we consider to be more accurate. A subset of the orientation points were derived from Dashevsky and others, 2003; their positional accuracy is unknown.

  3. How accurate are the heights or depths?

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

    This DGGS Preliminary Interpretive Report is meant to allow rapid release of field observations or initial interpretations of geology or analytical data. It has undergone limited peer review, but does not necessarily conform to DGGS editorial standards. Interpretations or conclusions contained in this publication are subject to change. This publication provides information about the mapped and interpreted geologic deposits distinguishable at a scale of about 1:63,600. The reader is cautioned that unevaluated hazards or uncertainties may be present in areas that were inecessable to field geologists.

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

    All polygon features were topologically validated using ArcGIS prior to export to shapefile format. Polygon topology is consistent with the specifications of the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1.


How can someone get a copy of the data set?

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

Access_Constraints:
This report, map, and/or dataset is available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below).
Use_Constraints:
Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way, the user is obligated to describe the types of modifications the user has made. The user specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys. The State of Alaska makes no express or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.

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

    Alaska Division of Geological & Geophysical Surveys
    Metadata Manager
    3354 College Road
    Fairbanks, AK 99709-3707
    USA

    (907)451-5020 (voice)
    (907)451-5050 (FAX)
    dggspubs@alaska.gov

    Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays
  2. What's the catalog number I need to order this data set?

    PIR 2017-3

  3. What legal disclaimers am I supposed to read?

    The State of Alaska makes no expressed or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.

  4. How can I download or order the data?


Who wrote the metadata?

Dates:
Last modified: 09-May-2018
Metadata author:
Alaska Division of Geological & Geophysical Surveys
Attn: Simone Montayne
Metadata Manager
3354 College Road
Fairbanks, AK 99709-3707
USA

(907)451-5020 (voice)
(907)451-5050 (FAX)
dggspubs@alaska.gov

Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:


Generated by mp version 2.9.21 on Wed May 9 11:30:54 2018