Identification_Information:
  Citation:
    Citation_Information:
      Originator: Day, Warren C.
      Originator: Aleinikoff, John N.
      Originator: Roberts, Paul 
      Originator: Smith, Moira 
      Originator: Gamble, Bruce M.
      Originator: Henning, Mitchell W.
      Originator: Gough, Larry P.
      Originator: Morath, Laurie C.
      Publication_Date: 2003
      Title: Geologic map of the Big Delta B-2 quadrangle, east-central Alaska
      Geospatial_Data_Presentation_Form: Map and GIS database
      Series_Information:
        Series_Name: U.S. Geological Survey Geologic Investigations Series
        Issue_Identification: I-2788
      Publication_Information:
        Publication_Place: Denver, Colorado
        Publisher: U.S. Geological Survey
      Online_Linkage: http://pubs.usgs.gov/imap/2003/I-2788

  Description:
    Abstract:
      New 1:63,360-scale geologic mapping of the Big Delta B-2 quadrangle
      provides important data on the structural setting and age of geologic
      units, as well as on the timing of gold mineralization plutonism within
      the Yukon-Tanana Upland of east-central Alaska.  Gold exploration has
      remained active throughout the region in response to the discovery of the
      Pogo gold deposit, which lies within the northwestern part of the
      quadrangle near the south bank of the Goodpaster River.  Geologic mapping
      and associated geochronological and geochemical studies by the U.S.
      Geological Survey (USGS) and the Alaska Department of Natural Resources,
      Division of Mining and Water Management, provide baseline data to help
      understand the regional geologic framework.  Teck Cominco Limited
      geologists have provided the geologic mapping for the area that overlies
      the Pogo gold deposit as well as logistical support, which has lead to a
      much improved and informative product.

      The Yukon-Tanana Upland lies within the Tintina province in Alaska and
      consists of Paleozoic and possibly older(?) supracrustal rocks intruded by
      Paleozoic (Devonian to Mississippian) and Cretaceous plutons.  The oldest
      rocks in the Big Delta B-2 quadrangle are Paleozoic gneisses of both
      plutonic and sedimentary origin.  Paleozoic deformation, potentially
      associated with plutonism, was obscured by intense Mesozoic deformation
      and metamorphism.  At least some of the rocks in the quadrangle underwent
      tectonism during the Middle Jurassic (about 188 Ma), and were subsequently
      deformed in an Early Cretaceous contractional event between about 130 and
      116 Ma.  New U-Pb SHRIMP data presented here on zircons from the Paleozoic
      biotite gneisses record inherited cores that range from 363 Ma to about
      2,130 Ma and have rims of euhedral Early Cretaceous metamorphic
      overgrowths (116 +/- 4 Ma), interpreted to record recrystallization during
      Cretaceous west-northwest-directed thrusting and folding.  U-Pb SHRIMP
      dating of monazite from a Paleozoic gneiss sample yields an age of 112 +/-
      2 Ma; the monazite presumably grew during the waning stages of the intense
      regional Cretaceous ductile deformation.  The Cretaceous ductile
      deformation was followed closely by granite plutonism and gold
      mineralization.  The main pulse of gold mineralization is temporally and
      spatially associated with the Cretaceous granitic dikes and plutons and
      occurred during regional uplift and extension.

    Purpose:
      This data set was developed to provide digital GIS data for the
      geologic map of the Big Delta B-2 quadrangle in east-central Alaska.

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

      Although this Federal Geographic Data Committee-compliant metadata file is
      intended to document the data set in nonproprietary form, as well as in
      ARC/INFO format, this metadata file may include some ARC/INFO-specific
      terminology.

      FILES INCLUDED IN THIS DATA SET:

      ARC/INFO coverages:
      faults:  arc coverage containing faults and thrusts
      geology:  polygon coverage containing geologic contacts and units
      strucplot:  point coverage containing strike and dip of foliation,
      lineations, and folds information

      Base map:
      bigdeltar.tif and bigdeltar.tfw

  Time_Period_of_Content:
    Time_Period_Information:
      Single_Date/Time:
        Calendar_Date: 2003
    Currentness_Reference: Publication date

  Status:
    Progress: Complete
    Maintenance_and_Update_Frequency: None planned

  Spatial_Domain:
    Bounding_Coordinates:
      West_Bounding_Coordinate: -145.0
      East_Bounding_Coordinate: -144.5
      North_Bounding_Coordinate: 64.5
      South_Bounding_Coordinate: 64.25

  Keywords:
    Theme:
      Theme_Keyword_Thesaurus: None
      Theme_Keyword: geology
      Theme_Keyword: faults
      Theme_Keyword: contacts
    Place:
      Place_Keyword_Thesaurus: None
      Place_Keyword: USA
      Place_Keyword: Alaska
      Place_Keyword: Big Delta B-2

  Access_Constraints: None

  Use_Constraints:
    These data were created with the intent of being used and displayed at a
    scale of 1:63,360.  Acknowledgment of the USGS would be appropriate in
    products derived from these data.  Any hardcopies utilizing these data sets
    shall clearly indicate their source.  If the user has modified the data in
    any way they are obligated to describe the types of modifications they have
    performed on the hardcopy map.  User specifically agrees not to misrepresent
    these data sets, nor to imply that changes were approved by the U.S.
    Geological Survey or the authors of this geologic map database.

  Point_of_Contact:
    Contact_Information:
      Contact_Person_Primary:
        Contact_Person: Warren C. Day
        Contact_Organization: U.S. Geological Survey
      Contact_Position: Geologist, Associate Chief Scientist
      Contact_Address:
        Address_Type: Mailing and physical address
        Address: USGS, Denver Federal Center, P.O. Box 25046, MS 964
        City: Denver
        State_or_Province: CO
        Postal_Code: 80225
        Country: USA
      Contact_Voice_Telephone: 303-236-6484
      Contact_Electronic_Mail_Address: wday@usgs.gov

  Data_Set_Credit:
    GEOLOGIC MAPPING:
    Warren C. Day (U.S. Geological Survey, Denver, CO)
    Bruce M. Gamble, Larry P. Gough (U.S. Geological Survey, Anchorage, AK)
    Mitchell W. Henning (Alaska Department of Natural Resources, Division of
    Mining and Water Management, Anchorage, AK)
    Paul Roberts, Moira Smith, and others (Teck Cominco Limited, #600-200
    Burrard Street, Vancouver, B.C., Canada V6C 3L9)

    DIGITIZATION AND DIGITAL FILE AND DATABASE CREATION:
    Laurie C. Morath (U.S. Geological Survey, Denver, CO)

  Native_Data_Set_Environment:
    Microsoft Windows 2000 Version 5.0 (Build 2195) Service Pack 2;
    ESRI ArcCatalog 8.2.0.700

Data_Quality_Information:
  Attribute_Accuracy:
    Attribute_Accuracy_Report:
      Attributes were checked by manually comparing hardcopy plots of the
      digital data with the source materials, and by completing tests within the
      software on each of the attribute tables.  Authors and Alex Donatich (USGS
      map editor) performed separate reviews.

  Logical_Consistency_Report:
    Coverage features were checked visually for overshoots, undershoots,
    duplications, polygon closures, and other errors by the author that created
    the digital databases, other report authors, and map editor.  ESRI ArcGIS
    8.1 and 8.2 (ARC/INFO modules) software were used to complete topological
    cleaning on each of the coverages.  Check plots were reviewed by USGS
    geologists (authors) and map editor for consistency with basic geologic
    principles and general conformity to USGS mapping standards.

  Completeness_Report: Data are complete

  Positional_Accuracy:
    Horizontal_Positional_Accuracy:
      Horizontal_Positional_Accuracy_Report:
        Geologic contacts and faults were plotted in the field and from field
        notes on a topographic mylar base map at a scale of 1:63,360.  The hand-
        drawn map was scanned, georeferenced, and digitized using heads-up
        digitizing techniques and ESRI ArcGIS 8.1 software.

  Lineage:
    Process_Step:
      Process_Description:
        Numerous field trips involving field mapping and note taking, resulting
        in a hand-drawn version of the map.
      Process_Date: 1998-2001

    Process_Step:
      Process_Description:
        Field map was scanned, georeferenced, and digitized, and arc (faults,
        geology) and polygon (geology) coverages were built.  Strucplot database
        was converted to a point coverage.
      Process_Date: 2001-2002

    Process_Step:
      Process_Description:
        Coverages were attributed and edited as necessary.  Hardcopies of
        coverages were field-checked.
      Process_Date: 2002

    Process_Step:
      Process_Description:
        Hardcopies were printed for several reviews by authors and map editor.
        Hardcopies were checked against source materials for accuracy and
        completeness.
      Process_Date: 2002-2003

    Process_Step:
      Process_Description: Database content was checked for accuracy and completeness.
      Process_Date: 2002-2003

Spatial_Data_Organization_Information:
  Direct_Spatial_Reference_Method: Vector
Spatial_Reference_Information:
  Horizontal_Coordinate_System_Definition:
    Planar:
      Map_Projection:
        Map_Projection_Name: Transverse Mercator
        Transverse_Mercator:
          Scale_Factor_at_Central_Meridian: 0.999600
          Longitude_of_Central_Meridian: -144.750000
          Latitude_of_Projection_Origin: 0.000000
          False_Easting: 0.000000
          False_Northing: 0.000000
      Planar_Coordinate_Information:
        Planar_Coordinate_Encoding_Method: coordinate pair
        Coordinate_Representation:
          Abscissa_Resolution: 0.000064
          Ordinate_Resolution: 0.000064
        Planar_Distance_Units: meters
    Geodetic_Model:
      Horizontal_Datum_Name: North American Datum of 1927
      Ellipsoid_Name: Clarke 1866
      Semi-major_Axis: 6378206.400000
      Denominator_of_Flattening_Ratio: 294.978698

Entity_and_Attribute_Information:
  Overview_Description:
    Entity_and_Attribute_Overview:
      The data set consists of three coverages:  FAULTS (linear features 
      representing faults and thrusts), GEOLOGY (polygon features representing 
      geologic units and associated linear features bounding geologic unit 
      polygons), and STRUCPLOT (point features representing strike and dip 
      attitudes of foliation, lineations, and folds).

      All data files were created using ESRI ArcGIS 8.1 (ARC/INFO module), and 
      edited later in ESRI ArcGIS 8.2 (ARC/INFO module).  Consequently, they 
      contain a number of fields that are created and maintained specifically 
      for those software packages.  The actual field characteristics are as 
      follows:

      Arc features of the FAULTS coverage (FAULT_TYPE indicates type of fault or 
      thrust; FAULT_NUM is an integer index corresponding to type of fault or 
      thrust):

      COLUMN   ITEM NAME   WIDTH   OUTPUT   TYPE   No.DEC
      1        FNODE#       4       5       BIN    --
      5        TNODE#       4       5       BIN    --
      9        LPOLY#       4       5       BIN    --
      13       RPOLY#       4       5       BIN    --
      17       LENGTH       8      18       FL      5
      25       FAULTS#      4       5       BIN    --
      29       FAULTS-ID    4       5       BIN    --
      33       OBJECTID     4      10       BIN    --
      37       FAULT_TYPE  50      50       CHAR   --
      87       FAULT_NUM    2       5       BIN    --

      Arc features of the GEOLOGY coverage (CONT_TYPE indicates type of contact; 
      CONT_NUM is an integer index corresponding to type of contact):

      COLUMN   ITEM NAME   WIDTH   OUTPUT   TYPE   No.DEC
      1        FNODE#       4       5       BIN    --
      5        TNODE#       4       5       BIN    --
      9        LPOLY#       4       5       BIN    --
      13       RPOLY#       4       5       BIN    --
      17       LENGTH       8      18       FL     5
      25       GEOLOGY#     4       5       BIN    --
      29       GEOLOGY-ID   4       5       BIN    --
      37       CONT_TYPE   30      30       CHAR   --
      87       CONT_NUM     2       6       BIN    --

      Polygon features of the GEOLOGY coverage (UNIT_SYMBO indicates geologic 
      unit symbol; UNIT_NAME describes type of geologic unit):

      COLUMN   ITEM NAME   WIDTH   OUTPUT   TYPE   No.DEC
      1        AREA         8      18       FL      5
      9        PERIMETER    8      18       FL      5
      17       GEOLOGY#     4       5       BIN    --
      21       GEOLOGY-ID   4       5       BIN    --
      25       OBJECTID     4      10       BIN    --
      29       UNIT_SYMBO  50      15       CHAR   --
      79       UNIT_NAME   50      50       CHAR   --

      Point features of the STRUCPLOT coverage (FIELD_NO is a unique 
      alphanumeric identification for each field locality; LAT_DD is latitude in 
      decimal degrees; LONG_DD is longitude in decimal degrees; DATE_ is date 
      point feature was measured; S1_STRIKE is strike in degrees; S1_DIP is dip 
      in degrees: L2_TREND is lineation trend in degrees; L2_PLUNGE is lineation 
      plunge in degrees; F2_TREND is F2 fold trend in degrees; F2_PLUNGE is F2 
      fold plunge in degrees; F3_TREND is F3 fold trend in degrees; F3_PLUNGE is 
      F3 fold plunge in degrees; POINT_TYPE indicates mapped point type; 
      POINT_NUM is an integer index corresponding to mapped point type):

      COLUMN   ITEM NAME     WIDTH   OUTPUT   TYPE   No.DEC
      1        AREA           4      12       FL      3
      5        PERIMETER      4      12       FL      3
      9        STRUCPLOT#     4       5       BIN    --
      13       STRUCPLOT-ID   4       5       BIN    --
      17       FIELD_NO      17      17       CHAR   --
      34       LAT_DD         8       8       FL      4
      42       LONG_DD        8       9       FL      4
      50       DATE_          8      10       DATE   --
      58       S1_STRIKE      8      11       FL      0
      66       S1_DIP         4       7       BIN    --
      70       L2_TREND       8      10       FL      0
      78       L2_PLUNGE      8      11       FL      0
      86       F2_TREND       8      10       FL      0
      94       F2_PLUNGE      8      11       FL      0
      102      F3_TREND       8      10       FL      0
      110      F3_PLUNGE      8      11       FL      0
      118      POINT_TYPE    50      50       CHAR   --
      168      POINT_NUM      2       5       BIN    --

      Some fields within each coverage's attribute table have a one-to-one 
      relationship with each other.  The following tables illustrate these 
      relationships as well as the frequency with which the relationships occur.

      Field value combinations in arc features of the FAULTS coverage:

      FREQUENCY   FAULT_TYPE                    FAULT_NUM
      48          Fault, Approximate Location   1
      65          Fault, Inferred Location      2
      69          Fault, Concealed              3
      12          Thrust, Approximate Location  4
      7           Thrust, Inferred Location     5
      3           Thrust, Concealed             6

      Field value combinations in arc features of the GEOLOGY coverage:

      FREQUENCY   CONT_TYPE                       CONT_NUM
      503         Contact, Approximate            1
      29          Contact, Inferred               2
      35          Contact, Coincident with Fault  3
      86          Map Boundary                    4

      Field value combinations in polygon features of the GEOLOGY coverage:

      FREQUENCY   UNIT_SYMBO   UNIT_NAME
      7           Qac          Alluvium and colluvium
      95          Qc           Colluvium
      1           Tb           Basalt
      15          Kgb          Goodpaster batholith
      5           Kdt          Diorite and tonalite
      1           Kgsp         Shawnee Peak intrusion
      1           Kgru         Granodiorite to granite, undivided
      14          Kgcd         Granitoid dike
      19          Kg           Granite stock
      2           Kgs          Granite of Swede Peak
      2           Ddg          Dioritic orthogneiss
      6           Dag          Augen gneiss
      17          Dog          Granodioritic orthogneiss
      9           Pzmg         Mafic gneiss
      4           Pzum         Ultramafic schist
      5           Pzq          Quartzite and metapelite
      21          Pzpg         Paragneiss
      1           Pzgn         Biotite-sillimanite gneiss
      2           Pzg          Biotite gneiss

      Field value combinations in point features of the STRUCPLOT coverage:

      FREQUENCY   POINT_TYPE                                  POINT_NUM
      3           F2 fold                                     1
      16          F3 fold                                     2
      3           Lineation and F3 fold                       3
      6           Lineation only                              4
      1           Strike and dip of foliation and F3 fold     5
      65          Strike and dip of foliation only            6
      73          Strike and dip of foliation with lineation  7

    Entity_and_Attribute_Detail_Citation: None

Distribution_Information:
  Distributor:
    Contact_Information:
      Contact_Organization_Primary:
        Contact_Organization: U.S. Geological Survey
      Contact_Address:
        Address_Type: Mailing and physical address
        Address: Central Publications Group
        Address: P.O. Box 25046, Federal Center, MS-902
        City: Denver
        State_or_Province: CO
        Postal_Code: 80225-0046
        Country: USA
      Contact_Voice_Telephone: 303-236-5486
  Resource_Description: I-2788
  Distribution_Liability:
    Although these data have been subjected to rigorous review and are 
    substantially complete, they are released on the condition that neither the 
    U.S. Geological Survey nor the Unites States Government may be held liable 
    for any damages resulting from their authorized or unauthorized use.
  Standard_Order_Process:
    Digital_Form:
      Digital_Transfer_Information:
        Format_Name: ARCE, SHP
        Format_Version_Number: ArcGIS v. 8.2
        File_Decompression_Technique: .tar.gz--UNIX gzip-compressed TAR 
          file(ARCE files)--use GNU zip and TAR.EXE; .zip--self-extracting 
          Window ZIP archive (SHP files)--execute file to extract
      Digital_Transfer_Option:
        Online_Option:
          Computer_Contact_Information:
            Network_Address:
              Network_Resource_Name: http://pubs.usgs.gov/imap/2003/i-2788/
    Fees: None

Distribution_Information:
  Distributor:
    Contact_Information:
      Contact_Organization_Primary:
        Contact_Organization: U.S. Geological Survey
      Contact_Address:
        Address_Type: Mailing address
        Address: USGS Information Services
        Address: PO Box 25286
        Address: Federal Center
        City: Denver
        State_or_Province: CO
        Postal_Code: 80225-0286
        Country: USA
      Contact_Voice_Telephone: (888) ASK-USGS
  Resource_Description: I-2788
  Distribution_Liability: None
  Standard_Order_Process:
    Non-digital_Form: Available as one printed sheet
    Fees: Contact USGS at the address listed above

Metadata_Reference_Information:
  Metadata_Date: 20030513
  Metadata_Contact:
    Contact_Information:
      Contact_Organization_Primary:
        Contact_Organization: U.S. Geological Survey
        Contact_Person: Laurie C. Morath
      Contact_Address:
        Address_Type: Mailing and physical address
        Address: USGS, Denver Federal Center, PO Box 25046, MS 973
        City: Denver
        State_or_Province: CO
        Postal_Code: 80225
      Contact_Voice_Telephone: 303-236-5361
  Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
  Metadata_Standard_Version: FGDC-STD-001-1998
  Metadata_Access_Constraints: None
  Metadata_Use_Constraints: None
  Metadata_Extensions:
    Online_Linkage: <http://www.esri.com/metadata/esriprof80.html>
    Profile_Name:
      ESRI Metadata Profile