Geologic map of Alaska (generalized)

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What does this data set describe?

Title: Geologic map of Alaska (generalized)
Digital data set used to produce a generalized geologic map of the state of Alaska. The digital data was derived from a detailed compilation and interpretation of published and unpublished geologic maps covering the state. The digital data from which this was derived is also provided in this publication.
  1. How might this data set be cited?
    Wilson, Frederic H., Labay, Keith, Shew, Nora, and Hults, Chad P., 2015, Geologic map of Alaska (generalized):.

    Online Links:

    This is part of the following larger work.

    Wilson, Frederic H., Hults, Chad P., Mull, Charles G., and Karl, Susan M., 2015, Geologic Map of Alaska: US Geological Survey Scientific Investigations Map SIM 3340.

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: 172.0
    East_Bounding_Coordinate: -130.0
    North_Bounding_Coordinate: 72.0
    South_Bounding_Coordinate: 51.2
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2015
    Currentness_Reference: Publication date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: Vector Digital Data Set (Polygon)
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • G-polygon (15466)
    2. What coordinate system is used to represent geographic features?
      The map projection used is NAD 1983 Alaska Albers (ESRI Full Name: NAD_1983_Alaska_Albers).
      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 0.6096
      Ordinates (y-coordinates) are specified to the nearest 0.6096
      Planar coordinates are specified in Meter
      The horizontal datum used is D_North_American_1983.
      The ellipsoid used is GRS_1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222101.
  7. How does the data set describe geographic features?
    Characteristics of the polygon features are coded in the attribute table. The table includes the following items: GROUP_ID, GROUP_SYMBOL, GROUP_LABEL, GROUP_LABEL2, GROUP_NAME, and GROUP_AGE. (Source: this data set)
    Unique numeric identifier of map units on the generalized geologic map of Alaska. (Source: this data set)
    Range of values
    Symbol number used to identify color in style file (Source: this data set)
    Range of values
    Geologic map unit label using special characters to designate geologic age symbols in FGDCGeoAge font. (Source: this data set) Special symbols used and the geologic age they represent are: } Mesozoic, ^ Triassic, | Paleozoic, * Pennsylvanian, _ Cambrian, and < Proterozoic. GROUP_LABEL correlates with Attribute_Label GROUP_LABEL2.
    Geologic map unit label used for the generalized geologic map of Alaska. Substitutes for special characters include IP for Pennsylvanian and Px for Proterozoic. (Source: this data set)
    buBedrock of unknown type or age or areas not mapped (unknown age)
    CaAdams Argillite (Cambrian)
    CDbrvVolcanic rocks and sills (Pennsylvanian? to Devonian)
    ClgLisburne Group, undivided (Carboniferous)
    ClgneWahoo, Alapah, and Wachsmuth Limestones (Lisburne Group) (Middle Pennsylvanian to Mississippian)
    ClgtkTupik and Kogruk Formations (Lisburne Group) (Pennsylvanian to Upper Mississippian)
    CPxtTindir Group (Cambrian? and Proterozoic)
    CPxwgWales Group, undivided (Cambrian to Proterozoic)
    CPxwnWickersham and Neruokpuk units (Cambrian and Proterozoic)
    CrcRainbow chert (Togiak-Tikchik Complex) (Carboniferous?)
    DasBimodal metavolcanic rocks (Devonian)
    DbfBeaucoup Formation, undivided (Devonian)
    DCbgBaird Group and similar rocks (Middle Devonian to upper Cambrian)
    DccKarheen and Cedar Cove Formations (Devonian)
    DCmtMetaturbidite marble and calcareous schist (Nome Complex) (Devonian to Cambrian)
    DCspSchist and phyllite of the Alaska Range (Devonian or older)
    DCwblFarewell basinal facies carbonate rocks (Devonian or older)
    DeghHunt Fork Shale (Endicott Group) (Devonian)
    DegnNoatak Sandstone (Endicott Group) (Upper Devonian)
    DgbGambier Bay Formation, undivided (Devonian)
    DOgiOlder plutonic rocks of southeast Alaska (Early Devonian to Ordovician)
    DOlsThin-bedded limestone (Lower Devonian to Ordovician)
    DOscShale, chert, and argillite (Lower Devonian to Ordovician)
    DOtuMetasedimentary and metavolcanic rocks of Tukpahlearik Creek, undivided (Devonian to Ordovician)
    DPxcnMetasedimentary and metavolcanic rocks of the Central Belt and Northern Thrust assemblage of Till and others (2008a) (Devonian to Proterozoic)
    DPxgaGneiss, amphibolite, schist, quartzite, and marble (Yukon-Tanana crystalline complex) (Devonian or older)
    DPxnlOlder carbonate rocks of northern Alaska (Lower Devonian to Proterozoic?)
    DPxsbBrooks Range schist belt (Devonian to Proterozoic)
    DPxsqPelitic schist and quartzite and mafic interbeds (Yukon-Tanana crystalline complex) (Devonian and older)
    DSsmShallow-marine, carbonate-dominated rocks (Devonian and Silurian)
    DSumOlder ultramafic rocks of southeast Alaska (Devonian and Silurian)
    DSvBasalt, andesite, and sedimentary rocks (Devonian)
    DvecWoodchopper Volcanics and Schwatka unit of Weber and others (1992) (Devonian)
    DZwpFarewell platform facies (Upper Devonian, Frasnian to Neoproterozoic)
    DZyfClastic and carbonate rocks of the Yukon Flats Basin (Devonian to Neoproterozoic?)
    DZykSedimentary and metasedimentary rocks of York terrane (Lower Devonian to Ordovician)
    lPDcfCalico Bluff and Ford Lake Shale, undivided (Lower Pennsylvanian to Devonian)
    lPMnNuka Formation (Carboniferous)
    lPsbUpper Saginaw Bay Formation and similar rocks of southeast Alaska (Pennsylvanian)
    JagBokan Mountain peralkaline granite and syenite (Middle Jurassic)
    JDmcMystic structural complex, undivided (Jurassic to Devonian)
    JDocIgneous rocks (Angayucham) (Jurassic to Devonian)
    JegrIntermediate to mafic plutonic rocks (Early Jurassic)
    JlPeEtivluk Group, undivided (Middle Jurassic to Pennsylvanian)
    JkGraywacke of Kulukak Bay of Hoare and Coonrad (1978) (Upper to Middle Jurassic)
    JlmgrPlutonic rocks (Late and Middle Jurassic)
    JMctCherty tuff and breccia (Angayucham) (Jurassic? to Mississippian)
    JMpsClastic and carbonate rocks, Porcupine River region (Jurassic to Mississippian)
    JPkKakhonak Complex and Tlikakila complex of Carlson and Wallace (1983) (Jurassic, Triassic, and older?)
    JPsCalcareous and metabasaltic schist and phyllite (Togiak-Tikchik Complex) (Early Jurassic to Permian)
    JPzcChulitna sequence, undivided (Jurassic to upper Paleozoic)
    JPzsNorthern Alaska sedimentary rocks (Middle Jurassic to Carboniferous)
    JsctShelikof and Chinitna Formations and Tuxedni Group (Middle Jurassic)
    JtkTalkeetna Formation (Early Jurassic)
    JTrkpLimestone and volcanic rocks of the Kenai Peninsula (Early Jurassic and Late Triassic, Norian)
    JTrmvTatina River volcanics of Bundtzen and others (1997a) (Mystic structural complex) (Jurassic and Triassic)
    JTrosNewenham ophiolite complex (Jurassic and Triassic)
    JTrschBlueschist of southern Alaska (Early Jurassic to Triassic)
    JTrsrSpiculitic rocks (Lower Jurassic and Upper Triassic)
    JZuMafic and ultramafic rocks in central, western, and northern Alaska (Jurassic to late Proterozoic)
    KccaCoquina and calcarenite (Lower Cretaceous)
    KcgcCalcareous graywacke and conglomerate (Lower Cretaceous, Albian to Aptian)
    KchfChugach accretionary complex (Cretaceous)
    KcvgCalcareous graywacke and mudstone, volcanic graywacke, and conglomerate (lower Upper or upper Lower Cretaceous)
    KDtTogiak-Tikchik Complex, undivided (Mesozoic to Devonian)
    KegGranodiorite and other plutonic rocks (Early Cretaceous, Aptian to Hauterivian)
    KfyFlysch (Upper and Lower? Cretaceous)
    KhsRocks of Hammond River shear zone of Till and others (2008a) (Cretaceous)
    KipcMafic igneous-clast conglomerate, sandstone, and mudstone (Lower Cretaceous)
    KJabAndesite and basalt (Early Cretaceous and Jurassic)
    KJgnGravina-Nuzotin unit (Lower Cretaceous and Upper Jurassic)
    KJguPlutonic rocks and dikes (Cretaceous to Jurassic)
    KJsFine-grained sedimentary and metasedimentary rocks (Cretaceous or Jurassic)
    KJseSaint Elias Suite of Gordey and Makepeace (2003) and similar rocks (Early Cretaceous and Late Jurassic)
    KJsnkStaniukovich and Naknek Formations, Kotsina Conglomerate, and similar rocks of southern Alaska (Lower Cretaceous to Jurassic, Pliensbachian)
    KJvpVolcano-plutonic complexes (Cretaceous and Jurassic)
    KJygYakutat Group, undivided (Lower Cretaceous and Upper Jurassic?)
    KJyhGraywacke of the Yenlo Hills (Cretaceous? and uppermost Jurassic)
    KkKuskokwim Group, undivided (Upper Cretaceous to upper Lower Cretaceous)
    KkeKemik Sandstone (Lower Cretaceous, Hauterivian)
    KkgFlysch and quartzite, Kandik Group and equivalents (Lower Cretaceous, Albian to Valanginian)
    KlgrIntermediate granitic rocks (Late Cretaceous)
    KmgrGranitic rocks of central and southeast Alaska (Cretaceous, Coniacian to Albian)
    KmigMigmatite and metaplutonic rocks (Cretaceous)
    KMmWest-central Alaska melange (Angayucham) (Cretaceous or older)
    KmsMafic and shoshonitic volcanic rocks (Early Cretaceous)
    KmssMarine sandstone and siltstone (Cretaceous, Cenomanian to Albian)
    KmucMcHugh and Uyak Complexes and similar rocks (Late Cretaceous)
    KnmtNonmarine to shelf sedimentary rocks (Tertiary? and Cretaceous)
    KnsSedimentary rocks of the North Slope (Cretaceous, Cenomanian to Albian)
    KokOkpikruak and Kongakut Formations (Lower Cretaceous)
    KpfPedmar Formation (Lower Cretaceous, Albian)
    KpsPelitic schist (Late Cretaceous)
    KPssKingak Shale, Shublik Formation, and Karen Creek Sandstone, undivided (Lower Cretaceous to Permian)
    KPzumMafic and ultramafic rocks in southern Alaska (Cretaceous to late Paleozoic)
    KsbSchrader Bluff Formation (Upper Cretaceous, Maastrichtian to Santonian)
    KsbfSeabee Formation and Hue Shale (Upper Cretaceous, Coniacian to Turonian)
    KsfgFoliated granitic rocks of southeast Alaska (middle Cretaceous?)
    KsmdShallow to moderate depth sedimentary rocks (Upper Cretaceous to upper Lower Cretaceous)
    KTrmKelp Bay Group, undivided (Cretaceous to Triassic)
    KTrvsVolcanic and sedimentary rocks of southwest Alaska (Cretaceous to Triassic?)
    KvgcVolcanic graywacke and conglomerate (Lower Cretaceous, Hauterivian and older)
    KvuVolcanic rocks, undivided (Cretaceous)
    KygVolcanic graywacke and mudstone (Lower Cretaceous)
    MDeEndicott Group, undivided (Mississippian to Devonian)
    MDegkKanayut Conglomerate and Noatak Sandstone, undivided (Endicott Group) (Lower Mississippian and Upper Devonian)
    MDipIyoukeen and Peratrovich Formations (Mississippian and Devonian)
    MDmgGranitic rocks and orthogneiss (Mississippian to Devonian)
    MDtsTotatlanika Schist (Yukon-Tanana crystalline complex) (Early Mississippian to Late Devonian)
    MDvGreenstone and schist (Togiak-Tikchik Complex) (Mississippian? and Devonian?)
    MgqGlobe quartzite of Weber and others (1992) (Mississippian)
    MkKayak Shale (Endicott Group) (Mississippian)
    MlgacAkmalik Chert and other black chert of the Lisburne Group (Mississippian)
    MlgkKuna Formation (Lisburne Group) (Mississippian)
    MlgnuNasorak and Utukok Formations (Lisburne Group) (Mississippian)
    MOkgKaskawulsh group of Kindle (1953) (Mississippian and older)
    MPxgsGneiss, schist, and amphibolite (Yukon-Tanana crystalline complex) (Mississippian, Devonian, and older)
    MzmMelanges (Mesozoic to Paleozoic)
    MzPzaMetamorphic rocks of Admiralty Island, undivided (Mesozoic to Paleozoic)
    MzPzcpMetamorphic rocks associated with the Coast plutonic complex of Brew and Morrell (1979b) (Triassic to Paleozoic)
    MzPzkaKisaralik anticlinorium of Box and others (1993) (Togiak-Tikchik Complex) (Jurassic metamorphism, early Mesozoic or Paleozoic protolith)
    MzPzmbMetabasite (Mesozoic and Paleozoic)
    OcChert of Interior Alaska (Ordovician)
    OCjrJones Ridge Limestone and related units (Ordovician to Cambrian)
    OCvFossil Creek Volcanics and similar rocks (Ordovician and Cambrian)
    OPxptOlder rocks of York terrane and Grantley Harbor Fault zone (Middle Ordovician to Proterozoic)
    PcsClastic and volcaniclastic rocks (Togiak-Tikchik Complex) (Permian)
    PDcfCannery Formation and Porcupine slate of Redman and others (1985), undivided (Permian to Devonian)
    PDmsSedimentary rocks of the Mystic structural complex (Permian to Devonian)
    PIPgiGranodiorite, syenite, and other granitic rocks (early Permian and Pennsylvanian)
    PIPsmStrelna Metamorphics and related rocks (early Permian to Middle Pennsylvanian)
    PlssLimestone and calcareous clastic rocks (Permian)
    PstcStep Conglomerate (lower Permian)
    PvAndesite and basalt of southern Alaska (early Permian)
    PxkdKatakturuk Dolomite (Proterozoic)
    PxqmBasement of the White Mountain sequence (Proterozoic)
    PxvBasalt and red beds member (Tindir Group) and Mount Copleston volcanic rocks of Moore (1987) (Proterozoic)
    PzcMarble (early Permian to early Paleozoic)
    PzcuBlack chert (lower Paleozoic, Devonian, or older)
    PzeEclogite and associated rocks (Yukon-Tanana crystalline complex) (Paleozoic)
    PzknKlondike Schist, Keevy Peak Formation, and similar rocks (Yukon-Tanana crystalline complex) (Permian to early Paleozoic)
    PzlsLimestone and marble (Paleozoic)
    PznpMetagabbro and metasedimentary rocks (Nome Complex) (Paleozoic?)
    PzPxgbGabbro and metagabbro (early Paleozoic and Proterozoic?)
    PzPxkgHigh-grade metamorphic rocks of the Seward Peninsula (earliest Paleozoic to Proterozoic)
    PzPxncNome Complex, undivided (early Paleozoic to Proterozoic)
    PzPxrqmPelitic and quartzitic schist of the Ruby terrane (early Paleozoic to Proterozoic?)
    PzZnclLayered sequence (Nome Complex) (Devonian to Neoproterozoic)
    QTgmYakataga and Tugidak Formations (Quaternary and uppermost Tertiary)
    QTmContact metamorphosed and hydrothermally altered rocks (Quaternary or late Tertiary)
    QTsUnconsolidated and poorly consolidated surficial deposits (Quaternary, Pleistocene, and uppermost Tertiary)
    QTviYoung volcanic and shallow intrusive rocks (Quaternary or late Tertiary)
    QTvsKiska Harbor and Milky River Formations (Quaternary? and late Tertiary)
    SCdaOlder rock units of the Doonerak Window (Silurian to Cambrian)
    SCwbcFarewell basinal facies clastic rocks (Silurian to upper Cambrian)
    SOigIviagik group of Martin (1970) (Silurian, Llandovery, to Ordovician)
    SOmiHeterogeneous metamorphic rocks, southeast Alaska (Silurian and Ordovician)
    SOpwSedimentary and volcanic rocks of Prince of Wales Island (Silurian, Llandovery, and Ordovician)
    SZfwrFour Winds complex of Gilbert and others (1987), Retreat Group, and orthogneiss (Silurian to Proterozoic)
    TbkBasalt and keratophyre (Tertiary, Paleogene, or older)
    TcbCoal-bearing sedimentary rocks (Tertiary, Pliocene to Eocene?)
    TccGneiss and amphibolite (Tertiary, Miocene)
    TclCopper Lake Formation (Tertiary, Eocene to Paleocene)
    TcpYounger phase, Coast plutonic complex of Brew and Morrell (1979b) (Tertiary, Eocene)
    TcppPorphyritic granodiorite phase of Coast plutonic complex of Brew and Morrell (1979b) (Tertiary, Eocene)
    TehiFelsic dikes, sills, and small stocks in southern Alaska (Tertiary and older?)
    TgbGabbroic rocks in southern Alaska (Tertiary)
    ThiHypabyssal intrusions (Tertiary)
    TkKootznahoo Formation (Tertiary, lower Miocene to upper Eocene)
    TKcfCanning Formation (lower Tertiary, Oligocene? to Cretaceous, Albian)
    TKgiGranitic rocks of southern and interior Alaska (Tertiary, Paleocene to Cretaceous, Maastrichtian)
    TKgrGhost Rocks Formation and similar rocks (Tertiary, Paleocene, and Upper Cretaceous)
    TKkfKrugoli Formation, undifferentiated (Tertiary, Paleogene, or Cretaceous)
    TKmMafic intrusive rocks (Tertiary to Late Cretaceous or older)
    TkntNearshore and nonmarine sedimentary rocks in southern Alaska (Tertiary)
    TKpcPrince Creek Formation (lower Tertiary, Paleocene, to Upper Cretaceous, Campanian)
    TKprFlows and pyroclastic rocks (early Tertiary to Late Cretaceous)
    TKsConglomerate, sandstone, and lignite (lower Tertiary to Upper Cretaceous)
    TKtspFoliated tonalite sill and pegmatite, Coast plutonic complex of Brew and Morrell (1979b) (Tertiary, Eocene? to latest Cretaceous)
    TmiYounger granitic rocks (Tertiary, Pliocene to Miocene)
    TMzmbMacLaren metamorphic belt of Smith and Lanphere (1971) (Tertiary to Jurassic or older?)
    TMzuBasement rocks, undifferentiated, Aleutian Islands (Tertiary or older)
    TngNenana Gravel (Tertiary, Pliocene and upper Miocene)
    ToegGranitic rocks in southern Alaska (Tertiary, Oligocene and Eocene)
    TogumMafic and ultramafic rocks of the Valdez and Orca Groups (Tertiary, Eocene to Paleocene)
    TogvVolcanic rocks of the Orca Group and Ghost Rocks Formation (Tertiary, Eocene to Paleocene)
    TopRedwood and Poul Creek Formations (Tertiary, Miocene to Eocene?)
    TovsSedimentary and volcanic rocks of the Orca Group, undivided (Tertiary, Eocene to Paleocene)
    TpgiGranitic intrusive rocks of the Chugach accretionary complex (Tertiary, Paleocene)
    TPziUndivided dikes and sills (Tertiary to Paleozoic?)
    TsfSagavanirktok Formation (Tertiary, Miocene to Paleocene)
    TskiSitkinak and Sitkalidak Formations (Tertiary, Oligocene to Eocene)
    TsmoSedimentary rocks of southwest Alaska (Tertiary, Miocene and Oligocene)
    TsuSedimentary rocks, undivided (Tertiary)
    TtsrSedimentary rocks of eastern Prince William Sound (Tertiary, Eocene)
    TvVolcanic rocks, undivided (Tertiary)
    TvcVictoria Creek metamorphic rocks (Tertiary, Paleocene metamorphism)
    TvcsVolcanic and sedimentary rocks (Tertiary, Oligocene and Eocene)
    TvmeOlder volcanic rocks, undivided (Tertiary, early Miocene to Eocene)
    TvpmYounger volcanic rocks, undivided (Tertiary, Pliocene and Miocene)
    TrcsCalcareous sedimentary rocks (Upper Triassic, middle? Norian and upper Carnian)
    TrDtzSedimentary rocks and chert (Angayucham) (Triassic to Devonian)
    TrgsShublik Formation and lower Glenn Shale (Triassic)
    TrhgHyd Group, undivided (Upper and Middle Triassic)
    TrlPmsSkolai and Mankomen Groups, undivided (Triassic to Pennsylvanian)
    TrlPsfFlysch-like sedimentary rocks (Triassic to Pennsylvanian)
    TrmbMassive basalt and greenstone (Triassic)
    TrmlsMarble and limestone of Wrangellia (Triassic)
    TrMsmSeventymile assemblage (Yukon-Tanana crystalline complex) (Triassic to Mississippian)
    TrPsgSadlerochit Group, undivided (Lower Triassic to Permian)
    TrPvsMetamorphic rocks, southeast Alaska (Triassic to Permian)
    TrPzbiMetamorphic rocks of Baranof Island (Triassic or older)
    TrPzgpMetagraywacke and phyllite (Triassic? and late Paleozoic)
    TrqdQuartz diorite and granodiorite (Triassic)
    TrsfShuyak Formation, undivided (Upper Triassic)
    XioKanektok metamorphic complex and Idono Complex (Paleoproterozoic)
    ZamMetasedimentary and metavolcanic rocks of Mount Angayukaqsraq (Neoproterozoic)
    ZgnGneiss of northern Alaska (Neoproterozoic)
    Name of geologic map unit on generalized geologic map of Alaska. (Source: this data set) Correlates with attributes GROUP_ID, GROUP_LABEL, and GROUP_LABEL2. See Attribute_Domain_Values for GROUP_LABEL2.
    Age of geologic map unit on generalized geologic map of Alaska. (Source: this data set) Correlates with attributes GROUP_ID, GROUP_LABEL, GROUP_LABEL2, and GROUP_NAME. See Attribute_Domain_Values for GROUP_LABEL2.
    Characteristics of the arc features are coded in the arc attribute table. The table includes the following items: ARC_CODE and LINE_TYPE. (Source: this data set)
    ARC_CODE is a positive integer value in the arc attribute table. Values range discontinuously from 4 to 91. Values match one-for-one with LINE_TYPE. (Source: this data set)
    4Normal fault, location certain
    5Normal fault, location approximate
    6Normal fault, location inferred or queried
    10Thrust fault, location certain; teeth on right from origin
    11Thrust fault, location approximate; teeth on right from origin
    12Thrust fault, location inferred or queried; teeth on right from origin
    14Caldera or crater rim
    28Concealed caldera or crater rim
    30Fault, unknown offset, certain location
    31Fault, unknown offset, approximate location
    32Fault, unknown offset, inferred location
    35High-angle reverse fault, certain location
    36High-angle reverse fault, approximate location
    37High-angle reverse fault, inferred location
    52Concealed normal fault
    53Concealed thrust fault
    54Concealed high-angle reverse fault
    55Concealed normal fault having right lateral oblique slip
    57Concealed right-lateral fault
    58Concealed left-lateral fault
    60Concealed fault of uncertain displacement
    71Normal fault, location certain, having right lateral oblique slip
    72Normal fault, location approximate, having right lateral oblique slip
    76Normal fault, inferred or queried, having right lateral oblique slip
    87Right lateral fault, location certain
    88Right lateral fault, location approximate
    89Right lateral fault, inferred or queried
    90Left lateral fault, location certain
    91Left lateral fault, location approximate
    Description of type of geologic line. (Source: this data set) Correlates with attribute ARC_CODE.

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?
  3. To whom should users address questions about the data?
    U.S. Geological Survey, Alaska Science Center
    Attn: Frederic H. Wilson
    Research Geologist
    4210 University Drive
    Anchorage, AK

    907-786-7448 (voice)

Why was the data set created?

This data set represents part of a systematic effort to release geologic map data for the United States in a uniform manner. Geologic data in this data set has been compiled from a wide variety of sources, published and unpublished, ranging from state and regional geologic maps to field mapping.

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: Unknown (process 1 of 4)
    The geology for each of the 153 1:250,000 scale quadrangles in Alaska was compiled from many different sources. Linework was hand digitized from materials of various media and scale. The arcs and polygons were attributed, and topology was checked. Data is archived as ARC/Info coverages.
    Date: 2015 (process 2 of 4)
    The geology data from the 153 quadrangle coverages were combined to create the detailed map feature classes in AKStategeol.gdb.
    Date: 2015 (process 3 of 4)
    The generalized map features were created from the detailed map features by this process. The detailed geologic units were combined using attribute GROUP_ID, and then rasterized with 100 m cells. The raster data was manipulated in several steps using GROUP_ID and area to reduce the amount of surficial units and water. It was also used to remove small areas and slivers of a generalized unit (GROUP_ID). The grid was converted to polygons, which were used to create labels and lines, and then the lines were smoothed and used to create new polygons with attributes from the new labels. These new polygons are AKStategeolpoly_generalized.
    Date: 2015 (process 4 of 4)
    AKStategeolarc_generalized is a subset of AKStategeol_arc, consisting of caldera rims and major faults.
  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?
    Many types of source materials of varying scales were used to compile this data set. Sources include previously published maps, unpublished mapping, and air photo interpretation, and reflects more than a century of work in Alaska. Vector features were mostly digitized either by digitizing on screen or on a large format digitizing tablet. Vectors and polygons were attributed and checked. Topology rules were checked.
  2. How accurate are the geographic locations?
    Data for the generalized geologic map is presented at 1:1,584,000 scale (or 1 inch = 25 miles). The parent data set 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?
    AKStategeolpoly_generalized and AKStategeolarc_generalized were derived from AKStategeol_poly and AKStategeol_arc respectively, in order to produce a simplified map for graphic presentation. The parent data sets contain more detailed mapping and information about the geology, including original map unit, age, lithology, and reference source. Detailed geologic unit descriptions are provided in the accompanying pamphlet.
  5. How consistent are the relationships among the observations, including topology?
    The geologic data consists of attributed arcs and polygons. Each polygon has a coded attribute designating the mapped geologic map unit. Faults, stratigraphic contacts, and other linear features are represented as arcs. When a fault is also a stratigraphic contact, only a single arc is present. Dangling arcs may be present (fault, dike, lineation, etc.).

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None.
None. Acknowledgment of the U.S. Geological Survey would be appreciated in products derived from these data.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey
    MS902 Box 25286 Denver Federal Center
    Lakewood, CO

    1-888-ASK-USGS (voice)
  2. What's the catalog number I need to order this data set? SIM 3340
  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?

Last modified: 04-Dec-2015
Metadata author:
U.S. Geological Survey, Alaska Science Center
Attn: Nora B. Shew
4210 University Drive
Anchorage, AK

907-786-7445 (voice)
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

Generated by mp version 2.9.32 on Fri Dec 4 13:04:52 2015