Lithology.gdb

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What does this data set describe?

Title: Lithology.gdb
Abstract:
Polygon features showing the distribution of various lithology types in Alaska. These data layers were derived from a statewide geology geospatial database containing attributes which generalize the lithologies of the geologic units. Each polygon feature class is also provided as a shapefile.
Supplemental_Information:
Frederic H. Wilson, Hults, Chad P., Mull, Charles G., and Karl, Susan, M., comps., 2015, Geologic map of Alaska: U.S. Geological Survey Scientific Investigations Map 3340, 196 p., 2 sheets, scale 1:584,000, http://dx.doi.org/10.3133/sim3340.
  1. How might this data set be cited?
    U.S. Geological Survey, 2016, Lithology.gdb:.

    This is part of the following larger work.

    Susan M. Karl (ed.), James V. Jones, III (ed.), and Timothy S. Hayes (ed.), 2016, GIS-based identification of areas that have resource potential for critical minerals in six selected groups of deposit types in Alaska: U.S. Geological Survey Open-File Report 2016-1191.

    Online Links:

    Other_Citation_Details:
    The larger work includes data sets for mineral resource data, geochemistry (stream sediment, rock, soil, mineral, and heavy mineral concentrate), igneous rock geochemical indices, aeroradiometric data, and hydrologic units analyzed for select deposit types.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: 172.0
    East_Bounding_Coordinate: -130.0
    North_Bounding_Coordinate: 71.4
    South_Bounding_Coordinate: 51.0
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2015Currentness_Reference: publication date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Vector data set.
    2. What coordinate system is used to represent geographic features?
      The map projection used is NAD 1983 Alaska Albers (Meters).
      Projection parameters:
      Standard_Parallel: 55.0
      Standard_Parallel: 65.0
      Longitude_of_Central_Meridian: -154.0
      Latitude_of_Projection_Origin: 50.0
      False_Easting: 0.0
      False_Northing: 0.0
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.001
      Ordinates (y-coordinates) are specified to the nearest 0.001
      Planar coordinates are specified in meters
      The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.4.
      The flattening of the ellipsoid used is 1/297.9786982.
  7. How does the data set describe geographic features?
    Carbonate_major
    Subset of the Alaska geology database in which lithology is categorized as 'Carbonate', 'Calc-silicate-rock', or 'Metacarbonate', and RANK is 'Major' or 'Indeterminate, major'. (Source: this data set)
    Carbonate_other
    Subset of the Alaska geology database in which lithology is categorized as 'Carbonate', 'Calc-silicate-rock', or 'Metacarbonate', and RANK is 'Minor', 'Incidental', or 'Indeterminate, major'. (Source: this data set)
    Ultramafic_major
    Subset of the Alaska geology database in which lithology is categorized as 'Gabbroic', 'Anorthosite', 'Ultramafic', 'Lamprophyre', 'Mafic-volcanic', 'Ultramafic-volcanic', 'Greenstone', 'Serpentinite', 'Mafic-hypabyssal' excluding 'Hypabyssal-andesite', 'Mafic-volcanic' excluding 'Andesite', 'Metadiabase', 'Metagabbro', 'Metaultramafic', 'Metadunite', 'Metaperidotite' or 'Metapyroxenite'. RANK is 'Major' or 'Indeterminate, major'. (Source: this data set)
    Ultramafic_other
    Subset of the Alaska geology database in which lithology is categorized as 'Gabbroic', 'Anorthosite', 'Ultramafic', 'Lamprophyre', 'Mafic-volcanic', 'Ultramafic-volcanic', 'Greenstone', 'Serpentinite', 'Mafic-hypabyssal' excluding 'Hypabyssal-andesite', 'Mafic-volcanic' excluding 'Andesite', 'Metadiabase', 'Metagabbro', 'Metaultramafic', 'Metadunite', 'Metaperidotite' or 'Metapyroxenite'. RANK is 'Minor' or 'Incidental'. (Source: this data set)
    Gravel_anthro
    Subset of the Alaska geology database in which the geologic unit is categorized as placer or anthropogenic deposits. (Source: this data set)
    Gravel_highlevel
    Subset of the Alaska geology database in which the geologic unit is categorized as Quaternary or Tertiary aged high-level gravel. (Source: this data set)
    Gravel_undivided
    Subset of the Alaska geology database in which the geologic unit is categorized as Quaternary or Tertiary aged older surficial deposits, undivided. (Source: this data set)
    Hypabyssal
    Subset of the Alaska geology database in which lithology is categorized as 'Hypabyssal'. No selection on RANK is made. (Source: this data set)
    Metaigneous
    Subset of the Alaska geology database in which lithology is categorized as 'Metaigneous'. No selection on RANK is made. (Source: this data set)
    Plutonic_major
    Subset of the Alaska geology database in which lithology is categorized as 'Plutonic' and RANK is 'Major' or 'Indeterminate, major'. (Source: this data set)
    Plutonic_other
    Subset of the Alaska geology database in which lithology is categorized as 'Plutonic' and RANK is 'Minor' or 'Incidental'. (Source: this data set)
    Volcanic
    Subset of the Alaska geology database in which lithology is categorized as 'Volcanic'. No selection on RANK is made. (Source: this data set)
    REE_lith_major
    Subset of the Alaska geology database in which lithology is categorized as 'Granitic' excluding 'Granodiorite' and 'Tonalite', 'Syenitic', 'Foidal-syenitic', 'Intrusive-carbonatite', or 'Felsic-hypabyssal'. RANK is 'Major' or 'Indeterminate, major'. (Source: this data set)
    Arkose
    Subset of the Alaska geology database in which lithology is categorized as 'Arkose'. No selection on RANK is made. (Source: this data set)
    Coal_unit
    Created from shapefile coalunit_poly.shp in publication Merritt, R.D., and Hawley, C.C., 1986, Map of Alaska's coal resources: Alaska Division of Geological and Geophysical Surveys Special Report 37, scale 1:2,500,000. Shapefile was converted to a geodatabase feature class and 2 fields, age and selection, were added. (Source: Alaska Division of Geological and Geophysical Surveys Special Report 37 and this data set.)
    id
    Field id is retained from the original shapefile. (Source: this data set) The only value in the dataset is 0; no definition available.
    RANK
    Coal rank is the classification or grade of coal. (Source: Alaska Division of Geological and Geophysical Surveys (ADGGS))
    ValueDefinition
    0No rank has been assigned.
    1Anthracite or semianthracite beds of mineable thickness - minimum 14 inches.
    2Anthracite or semianthracite - resource potential less certain.
    3Bituminous coal beds of mineable thickness - minimum 14 inches.
    4Bituminous coal - resource potential less certain.
    5Subbituminous coal underlain by bituminous coal - resource potential undefined.
    6Subbituminous coal beds of mineable thickness - minimum 30 inches.
    7Subbituminous coal - resource potential less certain.
    8Lignite underlain by subbituminous coal - resource potential undefined.
    9Lignite beds of mineable thickness - minimum 30 inches.
    10Lignite - resource potential less certain.
    UNIT
    Geologic unit (Source: ADGGS)
    ValueDefinition
    KcNorthern Alaska Province, mainly Corwin Formation of Nanushuk Group
    KcbYukon-Koyukuk Province, continental rocks, includes upper member Bergman Goup and Kaltak and Nulato Formations
    KccYukon-Koyukuk Province, continental rocks
    KcoNorthern Alaska Province, Colville Group
    KcvAlaska Peninsula Province, Chignik Formation, Coal Valley Member
    KkSouthwestern Alaska, continental to littoral marine rocks, includes Kuskokwim Group
    KmsNorthern Alaska Province, marine sedimentary rocks
    MkNorthern Alaska Province, Kapaloak Formation of Lisburne Group
    QTuNenana Province, Nenana Gravel and surficial deposits, undivided
    TarCook Inlet-Susitna Province, Arkose Ridge Formation
    TblAlaska Peninsula Province, Bear Lake Formation, Unga Conglomerate Member
    TbsCook Inlet-Susitna Province, Beluga and Sterling Formations, undivided
    TcCook Inlet-Susistna Province, Chickaloon Formation, lower member
    TcbNenana Province, continental rocks undivided
    TcbuCook Inlet-Susitna Province, continental rocks, undivided
    TccbUpper Yukon Province, continental rocks
    TclSoutheastern Alaska, continental rocks
    TclsSeward Peninsula Province, continental rocks
    TcuCook Inlet-Susitna Province, Chickaloon Formation, upper member
    TfOther coal-bearing areas, Frederika Formation
    TgaOther coal-bearing areas, Gakona Formation
    ThcNenana Province, Healy Creek Formation
    TkGulf of Alaska Province, Kushtaka Formation
    TkcGulf of Alaska Province, Kulthieth Formation
    TKcbUpper Yukon Province, continental rocks
    TkuCook Inlet-Susitna Province, sedimentary rocks, undivided. The label is Tku in polygon attribute table, but TKu on map sheet. The unit age is given as Tertiary-Cretaceous on the map sheet.
    TlsCook Inlet-Susitna Province, continental rocks
    TslNorthern Alaska Province, Sagavanirktok Formation
    TtCook Inlet-Susitna Province, Tyonek Formation
    TtsCook Inlet-Susitna Province, Tyonek Formation, Sandstone and Conglomerate Members
    TttCook Inlet-Susitna Province, Tyonek and Tsadaka Formations, undivided
    TuCook Inlet-Susitna Province, Kenai Group, undivided
    TuuNenana Province, Usibelli Group (includes Grubstake, Lignite Creek, Suntrana, Sanctuary, and Healy Creek Formations)
    TwfCook Inlet-Susitna Province, West Foreland Formation
    RANK_DESC
    Description of coal classification or grade. Correlates with RANK. (Source: ADGGS) free text
    age
    Geologic age of geologic unit as presented in original publication ADGGS Special Report 37. Null values are present. (Source: this data set) free text or null
    selection
    Field created to base age query for sandstone uranium HUC analysis. (Source: this data set)
    ValueDefinition
    yesGeologic unit is Tertiary or Upper Cretaceous in age.
    noGeologic age is not of Tertiary or Upper Cretaceous age.
    coalbearing
    Field created to base coal query for sandstone uranium HUC analysis. Null values are present. (Source: this data set)
    ValueDefinition
    yesGeologic unit is described as coal-bearing in ADGGS Special Report 37.
    Sandstone
    Subset of the Alaska geology database in which lithology is categorized as 'Clastic' but excluding 'Mudstone', 'Siltstone', 'Siltstone-mudstone', 'Graywacke', and ' Calcarenite', or 'Metaclastic' excluding 'Metasiltstone', 'Pelitic-schist', 'Phyllite', 'Slate', and 'Metagraywacke'. No selection on RANK is made. (Source: this data set)
    Sandstone_buffer
    The intersection of a 3 km outside only buffer around the Sandstone layer with unconsolidated sediments. (Source: this data set)
    Sandstone_Tert
    Subset of dataset Sandstone in which age is either 'Tertiary' or 'Tertiary and/or Cretaceous'. (Source: this data set)
    SnGranite_lith
    Subset of the Alaska geology database in which lithology is categorized as 'Granitic' excluding 'Granodiorite' and 'Tonalite', or 'Felsic-hypabyssal'. No selection on RANK is made. (Source: this data set)

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

Why was the data set created?

The lithology data layers were created to provide rock type information to estimate the potential of mineral resources in the state of Alaska.

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: 2015 (process 1 of 1)
    Polygons were selected from the Alaska state geology database based on the lithology attributes and relative abundance to create the lithology data sets. Once selected, the polygons were exported to a new data set, and then the polygons were dissolved into single part features. All attributes from the original geology dataset were dropped. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Nora Shew
    4210 University Drive
    Anchorage, Alaska
    USA

    907-786-7445 (voice)
    nshew@usgs.gov
  3. What similar or related data should the user be aware of?

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

  1. How well have the observations been checked?
    This dataset was derived from a geology data set intended for use at a nominal scale of 1:250,000. The lithologic coding in the Alaska geology database is based on the regional geologic unit. Geologic units are comprised of more than one rock type, therefore a particular area may be covered by more than one lithology layer. The relative abundance of each lithology in each geologic unit is a coded attribute. The coding schema uses 'Major' for greater or equal to 33 percent; 'Minor' if between 10 and 33 percent; 'Incidental' for less than 10 percent; and 'Indeterminate, major' if relative abundance is unknown.
  2. How accurate are the geographic locations?
    Data is presented for use at a nominal scale of 1:250,000.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Geologic data and knowledge is not uniform across the state of Alaska; therefore, the certainty of the distribution of lithologies is uneven. These datasets are created from the current best digital data available. The attributes from the original geology dataset are not included, however the digital geologic map is published data.
  5. How consistent are the relationships among the observations, including topology?
    The lithology feature classes consist of polygons. The polygons were selected from a state geology dataset based on the lithology and its relative abundance, and then the polygons were dissolved into single part features.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None
Use_Constraints:
None. Users are advised to read the metadata for the dataset thoroughly to understand appropriate use and data limitations.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey
    MS902
    Box 25286
    Denver Federal Center
    Lakewood, CO
    U.S.A.

    1-888-ASK-USGS (voice)
  2. What's the catalog number I need to order this data set? USGS Open-File Report 2016-1191
  3. What legal disclaimers am I supposed to read?
    This publication was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 29-Dec-2015
Last Reviewed: 06-Sep-2016
Metadata author:
U.S. Geological Survey
Attn: Nora Shew
4210 University Drive
Anchorage, AK
U.S.A.

907-786-7445 (voice)
nshew@usgs.gov
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

Generated by mp version 2.9.34 on Fri Nov 4 13:26:31 2016