Northeastern Tanacross geologic map, Tanacross D-1, D-2, C-1, and C-2 quadrangles, Alaska

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Frequently anticipated questions:

What does this data set describe?

Title:
Northeastern Tanacross geologic map, Tanacross D-1, D-2, C-1, and C-2 quadrangles, Alaska
Abstract:
The Mineral Resources section of the Alaska Division of Geological & Geophysical Surveys (DGGS) conducted 500 mi2 of 1:63,360-scale geologic mapping in the northeastern Tanacross Quadrangle (Tanacross D-1, and parts of the C-1, C-2, and D-2 quadrangles), located 15 miles southeast of Chicken, Alaska. The project took place during two periods: a reconnaissance mapping effort June 12-22, 2017, and a detailed campaign from June 18 to July 16, 2018. This map is located within an area of current industry interest; it includes the Taurus porphyry copper-gold-molybdenum +/- rhenium deposit and several other occurrence types, including gold, copper, and molybdenum in porphyritic intrusions, structurally controlled silver-lead-zinc prospects, and placer gold deposits. This map includes unconsolidated surficial deposits in the Tanacross D-1 Quadrangle, the eastern one-third of the Tanacross D-2 Quadrangle, the northern half of the Tanacross B-2 Quadrangle and the northeastern one-third of the Tanacross B-2 Quadrangle. Surficial geology was primarily mapped by interpreting 2.5-m-resolution SPOT 5 color-infrared and natural color red-green-blue (RGB) imagery collected in 2009 and 2010 and stereoscopic pairs of approximately 1:65,000-scale, false-color, infrared aerial photographs taken in 1978 and 1981. Surficial mapping was augmented with helicopter-supported fieldwork June 20-23, 2017 and July 3-4, 2018 to visit exposures and check geologic mapping. The complete report and digital data are available from the DGGS website: <http://doi.org/10.14509/30197>.
Supplemental_Information:
This digital data distribution package provides a geodatabase that portrays features presented in PIR 2019-6. Field names and values generally follow the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7 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: 
CorrelationOfMapUnits:    Geodatabase feature dataset(s) that depicts the map unit correlation chart; includes applicable unit designators, brackets, dividing lines, and text.	
CrossSection:    Geodatabase feature datasets of geologic cross-sections; includes applicable unit designators, brackets, dividing lines, and text.	
CartographicLines:    Cross-section transects.	
ContactsAndFaults:    Line features that depict faults and geologic contacts.	
ContactsAndFaults_surficial:    Line features that depict surficial 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.	
GenericPoints:    A point file that provides locations and labels for key geologic features or observations.	
GeochronPoints:    Geochronology sample location points and symbology.	
GeologicLines:    Key linear features that do not participate in map-unit topology. Examples: dikes, coal seams, ash beds, glacial features, anticline and syncline hinge-surface traces, etc.	
GeoMaterialDict:    This table provides definitions and a hierarchy for GeoMaterial names prescribed by the GeMS database schema.	
Glossary:    Non-spatial reference table that, for certain database fields, lists the terms that populate these fields along with their definitions and sources for these definitions.	
MapUnitPolys:    Polygons that record the distribution of mapped or interpreted bedrock geologic units.	
MapUnitPolys_surficial:    Polygons that record the distribution of mapped or interpreted bedrock 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.)	
OverlayMapUnitPolys:    Polygons that record the distribution of subsets of geologic units or features.	
RepurposedSymbols:    Non-spatial reference table that documents cases in which FGDC Standard symbols are supplemented with custom symbols or with FGDC symbols repurposed for the map.	
Stations:    Field observation locations and descriptions.
  1. How should this data set be cited?

    Wypych, Alicja, Hubbard, T.D., Naibert, T.J., Athey, J.E., Newberry, R.J., Sicard, K.R., Twelker, Evan, Werdon, M.B., Willingham, A.L., Wyatt, W.C., and Lockett, A.C., 2019, Northeastern Tanacross geologic map, Tanacross D-1, D-2, C-1, and C-2 quadrangles, Alaska: Preliminary Interpretive Report PIR 2019-6, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 20 p., 1 sheet, scale 1:63,360

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -141.654279
    East_Bounding_Coordinate: -140.999969
    North_Bounding_Coordinate: 64.001097
    South_Bounding_Coordinate: 63.612544

  3. What does it look like?

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

    Beginning_Date: 2017
    Ending_Date: 2019
    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 .00000001
      Ordinates (y-coordinates) are specified to the nearest .00000001
      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?

    CorrelationOfMapUnits, CorrelationOfAdjacentMapUnits
    Geodatabase feature dataset(s) 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 generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    CrossSectionA, CrossSectionB
    Geodatabase feature datasets of geologic cross-sections; includes applicable unit designators, brackets, dividing lines, and text. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS). This table is generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    CartographicLines
    Cross-section transects. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS). This table is generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, 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; STATEMAP Deliverable

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

    ValueDefinition
    NULLnot applicable

    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.

    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 generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, 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): Contact, Generic; Fault, Generic; Fault, Normal; Fault, Low-angle normal; Thrust Fault; Aeromagnetic Lineament; Electromagnetic Lineament; map boundary

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

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

    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

    existenceconfidence
    Indicates the degree of confidence and/or certainty in the interpretation of 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.
    probableIndicates that the author has enough observational and/or other supporting data to be somewhat confident in the scientific credibility of the interpretation of the feature, and the interpretation of the feature at the mapped scale fits the overall proposed geologic model.

    identityconfidence
    Indicates the author's level 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.

    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.

    locationconfidence
    Indicates the author's relative confidence and/or certainty in the interpreted location of a feature.. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    approximateThe interpretation of the feature at the mapped scale can be reasonably inferred from the supporting data and fits the overall proposed geologic model, but the extent and location are uncertain due to insufficient observations and/or supporting data.
    accurateThe 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.

    ContactsAndFaults_surficial
    Line features that depict surficial geologic contacts. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS). This table is generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, 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): Contact, Generic

    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.

    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:100
    Maximum:100
    Units:meters

    existenceconfidence
    Indicates the degree of confidence and/or certainty in the interpretation of 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.

    identityconfidence
    Indicates the author's level 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.

    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.

    locationconfidence
    Indicates the author's relative confidence and/or certainty in the interpreted location of a feature.. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    approximateThe interpretation of the feature at the mapped scale can be reasonably inferred from the supporting data and fits the overall proposed geologic model, but the extent and location are uncertain due to insufficient observations and/or supporting data.

    DataSourcePolys
    Polygons that delineate the data sources for various parts of the map. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS). This table is generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    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.

    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 generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    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 generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    GenericPoints, GenericPointsAnno
    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 generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, 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): pingo

    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:100
    Maximum:100
    Units:meters

    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
    QaAlluvium of modern stream channels
    Qat1Oldest terrace alluvium
    Qat2Old terrace alluvium
    Qat3Young terrace alluvium
    QcUndifferentiated colluvium
    QcaColluvial and alluvial valley-fill

    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.

    GeochronPoints, GeochronPointsAnno
    Geochronology sample location points and symbology. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS). This table is generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, 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): 40Ar/39Ar; U-Pb

    fieldsampleid
    The identifier assigned by the person who originally located the sample. (Source: Alaska Division of Geological & Geophysical Surveys)

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

    A generic example of a DGGS sample identifier: YYYYAAA9999XXXX; YY or YYYY= year, AAA=geologist's initials (one to three characters), 9999=unique station number, XXXX= optional alpha characters which indicate that multiple samples were collected at a given location or that multiple observations with possibly identical prefixes were recorded in the project database. Field stations observed by non-DGGS personnel use identifiers from the originating reference.

    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
    KgGranite
    KpdPika diorite
    KqpTaurus quartz-feldspar porphyry
    KvVolcanic flows, dikes, and plugs
    MDloLake George orthogneiss
    MdagDivide Mountain augen gneiss

    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:10
    Units:meters

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

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

    numericage
    The interpreted (preferred) age calculated from geochronological analysis. Note: units provided in AgeUnits field. (Source: Age sources are cited in the accompanying report and in the DataSources table.)

    Range of values
    Minimum:64
    Maximum:371

    agepluserror
    The upper age plus error calculated from geochronological analysis. Note: units provided in AgeUnits field. (Source: Age sources are cited in the accompanying report and in the DataSources table.)

    Range of values
    Minimum:0
    Maximum:23

    ageminuserror
    The lower age plus error calculated from geochronological analysis. Note: units provided in AgeUnits field. (Source: Age sources are cited in the accompanying report and in the DataSources table.)

    Range of values
    Minimum:0
    Maximum:23

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

    Units(s): Ma

    stationid
    Identifier assigned by the 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 differs from the DGGS standard station numbering format.

    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.

    analysissourceid
    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
    Key linear features that do not participate in map-unit topology. Examples: dikes, coal seams, ash beds, glacial features, anticline and syncline hinge-surface traces, etc. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS). This table is generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, 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): antiform; synform

    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.

    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:250
    Maximum:250
    Units:meters

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

    ValueDefinition
    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 the author's level of confidence in the identification and classification of the feature. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    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.

    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.

    locationconfidence
    Indicates the author's relative confidence and/or certainty in the interpreted location of a feature.. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    approximateThe interpretation of the feature at the mapped scale can be reasonably inferred from the supporting data and fits the overall proposed geologic model, but the extent and location are uncertain due to insufficient observations and/or supporting data.

    GeoMaterialDict
    This table provides definitions and a hierarchy for GeoMaterial names prescribed by the GeMS database schema. (Source: GeMS (Geologic Map Schema) - a standard format for digital publication of geologic maps by the USGS National Cooperative Geologic Mapping Program (NCGMP). This table is generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    Glossary
    Non-spatial reference table that, for certain database fields, lists the terms that populate these fields along with their definitions and sources for these definitions. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS) This table is generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    MapUnitPolys, MapUnitPolysAnno
    Polygons that record the distribution of mapped or interpreted bedrock geologic units. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS) This table is generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, 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
    KfgFred granitoid
    KgGranite
    KpdPika diorite
    KqpTaurus quartz-feldspar porphyry
    KtgdTaurus granodiorite
    KtpTimber granitoid
    KvVolcanic flows, dikes, and plugs
    KwpWitherspoon feldspar porphyry
    MDfaFortymile amphibolite
    MDfmbFortymile marble
    MDfmsFortymile interlayered quartzite and schist
    MDfoFortymile orthogneiss
    MDfpFortymile paragneiss
    MDlaLake George amphibolite
    MDlauSerpentinite and amphibolite
    MDlmsLake George Assemblage interlayered quartzite and semischist
    MDloLake George orthogneiss
    MDlomLake George orthogneiss, magnetic
    MDlpLake George paragneiss
    MDsqcCarbonaceous schist and quartzite
    MdagDivide Mountain augen gneiss
    PzgsGneiss and schist
    QbPrindle Volcano basanite
    TKcConglomerate and sandstone
    TrPzumSerpentinized ultramafic rocks

    identityconfidence
    Indicates the author's level 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.

    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
    5400CMYK value - C:50%, M:40%, Y:0%, K:0%
    5310CMYK value - C:50%, M:30%, Y:13%, K:0%
    36X0CMYK value - C:30%, M:60%, Y:100%, K:0%
    0XX0CMYK value - C:0%, M:100%, Y:100%, K:0%
    6X00CMYK value - C:60%, M:100%, Y:0%, K:0%
    0300CMYK value - C:0%, M:30%, Y:0%, K:0%
    6500CMYK value - C:60%, M:50%, Y:0%, K:0%
    0360CMYK value - C:0%, M:30%, Y:60%, K:0%
    07X0CMYK value - C:0%, M:70%, Y:100%, K:0%
    0X00CMYK value - C:0%, M:100%, Y:0%, K:0%
    34A0CMYK value - C:30%, M:40%, Y:8%, K:0%
    0500CMYK value - C:0%, M:50%, Y:0%, K:0%
    0700 pattern 328-KCMYK value - C:0%, M:70%, Y:0%, K:0%
    4600CMYK value - C:40%, M:60%, Y:0%, K:0%
    2700CMYK value - C:20%, M:70%, Y:0%, K:0%
    A200CMYK value - C:8%, M:20%, Y:0%, K:0%
    2200CMYK value - C:20%, M:20%, Y:0%, K:0%
    3300CMYK value - C:30%, M:30%, Y:0%, K:0%
    5100CMYK value - C:50%, M:13%, Y:0%, K:0%
    3320CMYK value - C:30%, M:30%, Y:20%, K:0%
    5540CMYK value - C:50%, M:50%, Y:40%, K:0%
    7440CMYK value - C:70%, M:40%, Y:40%, K:0%
    2300CMYK value - C:20%, M:30%, Y:0%, K:0%
    6X30CMYK value - C:60%, M:100%, Y:30%, K:0%
    05X0CMYK value - C:0%, M:50%, Y:100%, K:0%

    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.

    MapUnitPolys_surficial, MapUnitPolys_surficialAnno
    Polygons that record the distribution of mapped or interpreted bedrock geologic units. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS) This table is generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, 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
    QaAlluvium of modern stream channels
    QafAlluvial-fan deposits
    Qat1Oldest terrace alluvium
    Qat2Old terrace alluvium
    Qat3Young terrace alluvium
    QcUndifferentiated colluvium
    QcaColluvial and alluvial valley-fill
    QcfFine-grained colluvium and silt
    QclColluvial landslide deposits
    QcrRubble deposits
    QfpFloodplain alluvium
    QgdUndifferentiated glacial drift
    QhPlacer-mine tailings and artificial fills

    identityconfidence
    Indicates the author's level 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.

    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
    A point files that provide field station locations, symbology, and associated structure data (bedding attitudes, foliation attitudes, slip vectors measured at a point, etc.) (Source: Alaska Division of Geological & Geophysical Surveys (DGGS) This table is generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, 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): mineral lineation; foliation; stretched mineral; intersection lineation; bedding parallel schistosity; stretching lineation; schistosity; fold axis; gneissic layering; compositional layering; sill; dike wall; shear band; vein wall; fracture; slickenside; crenulation; fault; mylonitic foliation; cleavage; slickenline; axial plane; minor slip surface; striation; minor fault; rods; crenulation lineation; contact; axial planar cleavage; joint; left limb of fold; right limb of fold; igneous flow banding; vein trend; compaction foliation; boudins; lineation; hinge line; oxide streak

    azimuth
    Strike or trend, measured in degrees clockwise from geographic North, using right-hand rule (dip is to the right of azimuth direction). Note: Null values not permitted according to the GeMS 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:357
    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

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

    ValueDefinition
    NULLnot applicable

    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:10
    Units:meters

    identityconfidence
    Indicates the author's level 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 the orientation of pole to plane. Note: Null values not permitted according to the GeMS 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:5
    Units:degrees

    plotatscale
    The scale at which the observation should be plotted. (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0
    Maximum:2000

    stationid
    Identifier assigned by the 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 differs 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
    NULLBlank (NULL) field values indicate that a map unit value was not assigned.
    KfgFred granitoid
    KgGranite
    KqpTaurus quartz-feldspar porphyry
    KvVolcanic flows, dikes, and plugs
    KwpWitherspoon feldspar porphyry
    MDfaFortymile amphibolite
    MDfmsFortymile interlayered quartzite and schist
    MDfoFortymile orthogneiss
    MDfpFortymile paragneiss
    MDlaLake George amphibolite
    MDlauSerpentinite and amphibolite
    MDlmsLake George Assemblage interlayered quartzite and semischist
    MDloLake George orthogneiss
    MDlomLake George orthogneiss, magnetic
    MDlpLake George paragneiss
    MDsqcCarbonaceous schist and quartzite
    MdagDivide Mountain augen gneiss
    PzgsGneiss and schist
    TKcConglomerate and sandstone
    TrPzumSerpentinized ultramafic rocks

    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.

    orientationsourceid
    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.

    OverlayMapUnitPolys
    Polygons that record the distribution of subsets of geologic units or features. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS) This table is generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, 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
    HornfelsHornfelsed augen gneiss
    PegDikesPegmatite dike

    identityconfidence
    Indicates the author's level 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.

    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.

    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.

    RepurposedSymbols
    Non-spatial reference table that documents cases in which FGDC Standard symbols are supplemented with custom symbols or with FGDC symbols repurposed for the map. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS). This table is generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, by the USGS National Cooperative Geologic Mapping Program (NCGMP).)

    Stations
    Field observation locations and descriptions. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS). This table is generally organized according to the GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7, 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.

    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:200
    Units:meters

    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.
    KfgFred granitoid
    KgGranite
    KpdPika diorite
    KqpTaurus quartz-feldspar porphyry
    KtgdTaurus granodiorite
    KtpTimber granitoid
    KvVolcanic flows, dikes, and plugs
    KwpWitherspoon feldspar porphyry
    MDfaFortymile amphibolite
    MDfmbFortymile marble
    MDfmsFortymile interlayered quartzite and schist
    MDfoFortymile orthogneiss
    MDfpFortymile paragneiss
    MDlaLake George amphibolite
    MDlauSerpentinite and amphibolite
    MDlmsLake George Assemblage interlayered quartzite and semischist
    MDloLake George orthogneiss
    MDlomLake George orthogneiss, magnetic
    MDlpLake George paragneiss
    MDsqcCarbonaceous schist and quartzite
    MdagDivide Mountain augen gneiss
    PzgsGneiss and schist
    QbPrindle Volcano basanite
    QcUndifferentiated colluvium
    QcaColluvial and alluvial valley-fill
    QgdUndifferentiated glacial drift
    TKcConglomerate and sandstone
    TrPzumSerpentinized ultramafic rocks

    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.

    plotatscale
    The scale at which the observation should be plotted. (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0
    Maximum:2000

    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.

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

    Location method(s): GPS; Map coordinates listed on the borehole collar.; This point was incorrectly recorded by the field tablet. Point was moved during map production to approximate location on correct traverse.

    timedate
    NULL values indicate that the time and date of observation was not recorded (Source: Alaska Division of Geological & Geophysical Surveys)

    Data type = integer

    timedate
    Time and date of observation at station. (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:6/13/2017 10:09
    Maximum:7/9/2018 23:58
    Units:meters

    observer
    Name of the person who observed and described the station (Source: Alaska Division of Geological & Geophysical Surveys)

    Observer(s): wcwyatt; etwelker; mbwerdon; krsicard; rjnewberry; tjnaibert; awypych; ssmasterman; jeathey; alwillingham; aclockett; rlflynn; wcmunley; djszumigala; tdhubbard

    gpsx
    NULL values indicate that the originating GPS coordinates have errors or that the station coordinates were not acquired by GPS. (Source: Alaska Division of Geological & Geophysical Surveys)

    Data type = integer

    gpsx
    Station coordinates downloaded from GPS (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:-141.7062762
    Maximum:-140.9921898
    Units:meters

    gpsy
    NULL values indicate that the originating GPS coordinates have errors or that the station coordinates were not acquired by GPS. (Source: Alaska Division of Geological & Geophysical Surveys)

    Data type = integer

    gpsy
    Station coordinates downloaded from GPS (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:63.6087299
    Maximum:63.99963032
    Units:meters

    mapx
    Station coordinate (easting) as compiled on the base map. (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:465037.7998
    Maximum:500384.1635
    Units:meters

    mapy
    Station coordinate (northing) as compiled on the base map. (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:7053489.057
    Maximum:7097705.12
    Units:meters

    gps_srs
    Spatial reference system of the originating GPS coordinates. (Source: Alaska Division of Geological & Geophysical Surveys)

    text

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?

    The DGGS Northeastern Tanacross project was funded by the USGS National Cooperative Geologic Mapping Program under STATEMAP award number G18AC00137 for 2018 and by State of Alaska general funds.

  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?

This map is located within an area of current industry interest; it includes the Taurus porphyry copper-gold-molybdenum +/- rhenium deposit and several other occurrence types, including gold, copper, and molybdenum in porphyritic intrusions, structurally controlled silver-lead-zinc prospects, and placer gold deposits. The northeastern Tanacross Quadrangle is characterized by a very complex geologic history and prior to DGGS work in the area, the most-detailed mapping was at 1:250,000 scale. DGGS mapping will provide detailed geologic context for the known porphyry systems in the map area and links to mineral occurrences elsewhere in the region, including structural detail linking the porphyries to mineral occurrences in western Yukon, Canada.

How was the data set created?

  1. From what previous works were the data drawn?

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

    Date: 2018 (process 1 of 4)
    Bedrock mapping - The Mineral Resources section of the Alaska Division of Geological &amp; Geophysical Surveys (DGGS) conducted 500 mi2 of 1:63,360-scale geologic mapping in the northeastern Tanacross Quadrangle (Tanacross D-1, and parts of the C-1, C-2, and D-2 quadrangles), located 15 miles southeast of Chicken, Alaska. The project took place during two periods: a reconnaissance mapping effort June 12-22, 2017, and a detailed campaign from June 18 to July 16, 2018. To create this map we incorporated (1) geologic information from previous geologic mapping and published literature, (2) new interpretations using remotely sensed imagery, and (3) information gathered from limited field investigations. A complete list of references is available in the accompanying report.

    Date: 2018 (process 2 of 4)
    Surficial geology - Surficial geology was mapped by interpreting 2.5-m-resolution SPOT 5 color-infrared and natural color red-green-blue (RGB) imagery collected in 2009 and 2010 and stereoscopic pairs of approximately 1:65,000-scale, false-color, infrared aerial photographs taken in 1978 and 1981. SPOT 5 imagery was interpreted in ArcGIS Pro by overlaying it on hillshade and slopeshade images derived from Interferometric Synthetic Aperture Radar (IFSAR) bare-earth digital-elevation models (DEMs) created using data collected in 2010. By using the pseudo-3-D functionality of ArcGIS Pro and adjusting the transparency of the SPOT 5 imagery and the transparency and color of hillshade and slopeshade images, we were able to visualize subtle differences in features and identify geologic landforms. We used aerial photographs to identify geologic features and check our interpretations. Geospatial polygon features, representing geologic units, were drawn using onscreen digitizing techniques in ArcGIS Pro. We conducted helicopter-supported fieldwork June 20-23, 2017 and July 3-4, 2018. During fieldwork we visited exposures and dug soil pits to examine material and gather information for unit descriptions and check geologic mapping. We also measured the thickness of the active layer at several locations.

    Date: 2019 (process 3 of 4)
    GIS analysis and digital cartography - The geologic and geographic features portrayed in this data distribution package were attributed according to the GeMS (Geologic Map Schema) geodatabase standard. https://ngmdb.usgs.gov/Info/standards/GeMS/

    Date: 2019 (process 4 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.

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

    Naibert, T.J., Benowitz, J.A., Wypych, Alicja, Sicard, K.R., and Twelker, Evan, 2018, 40Ar/39Ar data from the Tanacross D-1 and D-2, Big Delta B-4 and B-5, and Mount Hayes A-6 quadrangles, Alaska: Raw Data File RDF 2018-3, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 15 p
    Todd, Erin, Wypych, Alicja, and Kylander-Clark, Andrew, 2019, U-Pb and Lu-Hf isotope, age, and trace element data from zircon separates from the Tanacross D-1, and parts of D-2, C-1, and C-2 quadrangles: Raw Data File RDF 2019-5, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 10 p
    Wypych, Alicja, Naibert, T.J., Athey, J.E., Newberry, R.J., Sicard, K.R., Twelker, Evan, Werdon, M.B., Willingham, A.L., and Wyatt, W.C., 2018, Major-oxide and trace-element geochemical data from rocks collected in 2018 for the Northeast Tanacross project, Tanacross C-1, C-2, D-1, and D-2 quadrangles, Alaska: Raw Data File RDF 2018-4, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 4 p
    Wypych, Alicja, Twelker, Evan, Athey, J.E., Lockett, A.C., Naibert, T.J., Sicard, K.R., Werdon, M.B., and Willingham, A.L., 2017, Major-oxide and trace-element geochemical data from rocks collected in the Tanacross C-1, D-1, and D-2 quadrangles, Alaska in 2017: Raw Data File RDF 2017-10, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 4 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.

  3. How accurate are the heights or depths?

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

    The DGGS Preliminary Interpretive Report series is intended for the timely release of maps and reports with preliminary interpretation of geology or analytical data. This publication provides information about the mapped and interpreted geologic deposits distinguishable at a scale of about 1:63,600 and has received technical review. It may be cited as an agency publication.

  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 GeMS(Geologic Map Schema) a standard format for digital publication of geologic maps, V2 DRAFT 7.

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 2019-6

  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: 06-Sep-2019
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 Mon Sep 16 12:07:43 2019