Identification_Information:
  Citation:
    Citation_Information:
      Originator: Bove, Dana J.
      Originator: Hon, Ken
      Originator: Budding, Karin E.
      Originator: Slack, John F.
      Originator: Snee, Lawrence W.
      Originator: Yeoman, Ross A.
      Title: Geochronology and geology of late Oligocene through Miocene volcanism and mineralization in the western San Juan mountains, Colorado
      Publication_Date: 1999
      Series_Information:
        Series_Name: Open-File Report
        Issue_Identification: 99-347
      Publication_Information:
        Publication_Place: Denver, Colorado
        Publisher: Geological Survey (U.S.)
      Online_Linkage: http://pubs.usgs.gov/of/1999/ofr-99-0347/
  Description:
    Abstract: New age determinations with descriptions of sample locations and analytical details.
    Purpose:
      Our goal was to obtain more precise ages from a variety of fresh and
      mineralized rocks to clarify key relationships between caldera
      formation and mineralization in the western San Juan Mountains. We
      have obtained a series of new 40Ar/39Ar ages from the main
      calc-alkaline ashflow sheets and related younger calc-alkaline
      plutons, the ash-flows and lavas of the Lake City caldera cycle, and
      veins and other altered rocks in the Lake City region. Although
      these ages do not alter the general geological story of the western
      San Juan Mountains, they provide a much more precise chronological
      framework for interpreting durations of events and their
      relationship to mineralization
  Time_Period_of_Content:
    Time_Period_Information:
      Single_Date/Time:
        Calendar_Date: 1999
    Currentness_Reference: publication date
  Status:
    Progress: Complete
    Maintenance_and_Update_Frequency: None planned
  Spatial_Domain:
    Bounding_Coordinates:
      West_Bounding_Coordinate: -107.748889
      East_Bounding_Coordinate: -107.195278
      North_Bounding_Coordinate: 38.393333
      South_Bounding_Coordinate: 37.771944
  Access_Constraints: none
  Use_Constraints: none
  Keywords:
    Theme:
      Theme_Keyword_Thesaurus: Alexandria Digital Library Feature Type Thesaurus
      Theme_Keyword: craters
    Place:
      Place_Keyword_Thesaurus: Augmented FIPS 10-4 and FIPS 6-4
      Place_Keyword: f08051 = Gunnison
      Place_Keyword: f08053 = Hinsdale
      Place_Keyword: f08091 = Ouray
      Place_Keyword: f08111 = San Juan
    Theme:
      Theme_Keyword_Thesaurus: General glossary for mineral resources spatial data
      Theme_Keyword: DBF
      Theme_Keyword: shapefile
    Theme:
      Theme_Keyword_Thesaurus: Lithologic classification of geologic map units
      Theme_Keyword: Ash-flow tuff
      Theme_Keyword: Rhyolite
    Theme:
      Theme_Keyword_Thesaurus: USGS Thesaurus
      Theme_Keyword: geochronology
      Theme_Keyword: geologic history
      Theme_Keyword: geospatial datasets
      Theme_Keyword: miocene
      Theme_Keyword: oligocene
      Theme_Keyword: ore formation
      Theme_Keyword: potassium-argon analysis
      Theme_Keyword: radiometric dating
      Theme_Keyword: volcanic activity
      Theme_Keyword: volcanic rocks
  Point_of_Contact:
    Contact_Information:
      Contact_Person_Primary:
        Contact_Person: John F Slack
        Contact_Organization: USGS ER MW GD
      Contact_Address:
        Address_Type: mailing address
        Address:
          12201 Sunrise Valley Drive
          Mail Stop 954
        City: Reston
        State_or_Province: VA
        Postal_Code: 20192-0002
        Country: USA
      Contact_Voice_Telephone: 703-648-6337
      Contact_Facsimile_Telephone: 703-648-6383
      Contact_Electronic_Mail_Address: jfslack@usgs.gov
Spatial_Data_Organization_Information:
  Direct_Spatial_Reference_Method: Point
  Point_and_Vector_Object_Information:
    SDTS_Terms_Description:
      SDTS_Point_and_Vector_Object_Type: Entity point
      Point_and_Vector_Object_Count: 31
Spatial_Reference_Information:
  Horizontal_Coordinate_System_Definition:
    Geographic:
      Geographic_Coordinate_Units: decimal degrees
    Geodetic_Model:
      Horizontal_Datum_Name: North American Datum of 1983
      Ellipsoid_Name: Geodetic Reference System 80
      Semi-major_Axis: 6378137
      Denominator_of_Flattening_Ratio: 298.257
Entity_and_Attribute_Information:
  Detailed_Description:
    Entity_Type:
      Entity_Type_Label: samples.dbf
      Entity_Type_Definition: Sample locations and site characteristics, table A1 of the report
    Attribute:
      Attribute_Label: SAMPLE_ID
      Attribute_Definition: Sample identification number
    Attribute:
      Attribute_Label: DMSLAT
      Attribute_Definition: Geographic latitude in degrees, minutes, and seconds
    Attribute:
      Attribute_Label: LATITUDE
      Attribute_Definition: Geographic latitude in decimal degrees
    Attribute:
      Attribute_Label: DMSLONG
      Attribute_Definition: Geographic longitude in degrees, minutes, and seconds
    Attribute:
      Attribute_Label: LONGITUDE
      Attribute_Definition: Geographic longitude in decimal degrees
    Attribute:
      Attribute_Label: QUAD_NAME
      Attribute_Definition: Name of USGS map quadrangle from which the sample was taken
    Attribute:
      Attribute_Label: ELEV_M
      Attribute_Definition: Elevation in meters
    Attribute:
      Attribute_Label: DESC
      Attribute_Definition: Description of the sample
  Detailed_Description:
    Entity_Type:
      Entity_Type_Label: ArArage.dbf
      Entity_Type_Definition: Argon-Argon age determinations of samples, table 1 of the report
    Attribute:
      Attribute_Label: SAMPLE_ID
      Attribute_Definition: Sample identification number
    Attribute:
      Attribute_Label: MAP_FIG_NO
      Attribute_Definition: Index number of the location indicated on the maps figures 2a,b
    Attribute:
      Attribute_Label: ROCK_TYPE
      Attribute_Definition: Formation name and general rock type
    Attribute:
      Attribute_Label: AGE_DESC
      Attribute_Definition: General category of rock sample
    Attribute:
      Attribute_Label: LOCALITY
      Attribute_Definition: General location
    Attribute:
      Attribute_Label: DISTURBED
      Attribute_Definition: Indication as to whether the spectrum was disturbed
    Attribute:
      Attribute_Label: MIN_DATED
      Attribute_Definition: Mineral dated
    Attribute:
      Attribute_Label: PLATEAU
      Attribute_Definition: Plateau age in Ma
    Attribute:
      Attribute_Label: PLATEAU_U
      Attribute_Definition: Plateau age uncertainty
    Attribute:
      Attribute_Label: AVE_MEAN
      Attribute_Definition: Average weighted mean age in Ma
    Attribute:
      Attribute_Label: AVE_MEAN_U
      Attribute_Definition: Average weighted mean age uncertainty
    Attribute:
      Attribute_Label: RESET
      Attribute_Definition: Reset age in Ma
    Attribute:
      Attribute_Label: RESET_U
      Attribute_Definition: Reset age uncertainty
    Attribute:
      Attribute_Label: ISOCHRON
      Attribute_Definition: Isochron age in Ma
    Attribute:
      Attribute_Label: ISOCHRON_U
      Attribute_Definition: Isochron age uncertainty
    Attribute:
      Attribute_Label: PREFER
      Attribute_Definition: Preferred age in Ma
    Attribute:
      Attribute_Label: PREFER_U
      Attribute_Definition: Preferred age uncertainty
  Detailed_Description:
    Entity_Type:
      Entity_Type_Label: KArage.dbf
      Entity_Type_Definition: Potassium-argon age data for rhyolitic rocks in the Lake City area, table A2 of the report
    Attribute:
      Attribute_Label: SAMPLE_NO
      Attribute_Definition: Sample identification number
    Attribute:
      Attribute_Label: MAP_FIG_NO
      Attribute_Definition: Index number of the location indicated on the maps figures 2a,b
    Attribute:
      Attribute_Label: SAMP_DESC
      Attribute_Definition: Formation name and general rock type
    Attribute:
      Attribute_Label: MINERAL
      Attribute_Definition: Mineral dated
    Attribute:
      Attribute_Label: NA2O_PCT1
      Attribute_Definition: Sodium oxide concentration in weight percent (one of two determinations)
    Attribute:
      Attribute_Label: NA2O_PCT2
      Attribute_Definition: Sodium oxide concentration in weight percent (two of two determinations)
    Attribute:
      Attribute_Label: K2O_PCT1
      Attribute_Definition: Potassium oxide concentration in weight percent (one of two determinations)
    Attribute:
      Attribute_Label: K2O_PCT2
      Attribute_Definition: Potassium oxide concentration in weight percent (two of two determinations)
    Attribute:
      Attribute_Label: 40AR
      Attribute_Definition: Argon-40 concentration (units 10E10 moles per gram)
    Attribute:
      Attribute_Label: 40AR_PCT
      Attribute_Definition: Argon-40 as a percentage of total Argon
    Attribute:
      Attribute_Label: AGE_MA
      Attribute_Definition: Age in Ma
    Attribute:
      Attribute_Label: AGE_MA_U
      Attribute_Definition: Age uncertainty
Distribution_Information:
  Distributor:
    Contact_Information:
      Contact_Organization_Primary:
        Contact_Organization: USGS Information Services
      Contact_Address:
        Address_Type: mailing
        Address: Box 25286, Denver Federal Center
        City: Denver
        State_or_Province: Colorado
        Postal_Code: 80255-0046
        Country: USA
      Contact_Voice_Telephone: 1-888-ASK-USGS
      Contact_Facsimile_Telephone: 1-303-202-4695
      Contact_Electronic_Mail_Address: infoservices@usgs.gov
  Resource_Description: USGS Open-File Report 99-347
  Distribution_Liability:
    This report is preliminary and has not been reviewed for
    conformity with U.S. Geological Survey editorial standards (or
    with the North American Stratigraphic Code).  Any use of trade,
    product, or firm names is for descriptive purposes only and does
    not imply endorsement by the U.S. Government.
  Standard_Order_Process:
    Digital_Form:
      Digital_Transfer_Information:
        Format_Name: Shapefile
        Format_Version_Number: 1.0
        Format_Information_Content: Sample site information and geologic age estimates
        File_Decompression_Technique: unzip
      Digital_Transfer_Option:
        Online_Option:
          Computer_Contact_Information:
            Network_Address:
              Network_Resource_Name: http://pubs.usgs.gov/of/1999/ofr-99-0347/data/of99-347.zip
    Fees: none
Metadata_Reference_Information:
  Metadata_Date: 20080711
  Metadata_Contact:
    Contact_Information:
      Contact_Person_Primary:
        Contact_Person: Peter N Schweitzer
        Contact_Organization: USGS ER GD
      Contact_Position: Geologist
      Contact_Address:
        Address_Type: mailing address
        Address: 12201 Sunrise Valley Drive
        City: Reston
        State_or_Province: VA
        Postal_Code: 20192-0002
        Country: USA
      Contact_Voice_Telephone: 703-648-6533
      Contact_Facsimile_Telephone: 703-648-6252
      Contact_Electronic_Mail_Address: pschweitzer@usgs.gov
  Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata
  Metadata_Standard_Version: FGDC-STD-001-1998