Identification_Information:
  Citation:
    Citation_Information:
      Originator: Douglas B. Yager
      Publication_Date: 2008
      Title:
        Net Acid Production, Acid Neutralizing Capacity, and Associated
        Mineralogical, and Geochemical Characteristics of Animas
        River Watershed Rocks Near Silverton, Colorado
      Edition: 1.0
      Geospatial_Data_Presentation_Form: point location map and database
      Series_Information:
        Series_Name: USGS Scientific Investigations Report
        Issue_Identification: SIR 2008-5063
      Publication_Information:
        Publication_Place: Denver, Colorado
        Publisher: U.S. Geological Survey
      Online_Linkage: <http://pubs.usgs.gov/sir/2008/5063

  Description:
    Abstract:
      This point coverage, "ancUTM", presents results from laboratory studies
      involving the net acid production (NAP), and acid neutralizing capacity
      and magnetic mineralogy of 48 samples collected in the Upper Animas
      River watershed near Silverton, Colo., during the Summer and Fall of 2003
      to 2005.  Sampling focused mainly on the volumetrically important,
      Tertiary-age volcanic and plutonic rocks that are host to base and
      precious metal mineralization in the study area. Rocks in the study have
      all been subjected to a regional propylitic alteration event that modified
      the primary mineralogy of the host rock, while introducing minerals with
      an acid neutralizing capacity (ANC)including calcite, chlorite and epidote.
      Locally, hydrothermal alteration has consumed any ANC and introduced
      minerals, mainly pyrite, that has a high net acid production (NAP).
      Laboratory studies included hydrogen peroxide (H2O2) acid digestion and
      subsequent sodium hydroxide (NaOH) titration to determine NAP, and
      sulfuric acid H2SO4 acid titration experiments to determine ANC on
      selected samples that generally had low NAP.  In addition to these
      environmental rock property determinations, mineralogical, chemical, and
      petrographic characteristics of each sample were determined through
      multiple methods including semi-quantitative X-ray diffractometry
      (Rietveld method), optical mineralogy, wavelength dispersive X-ray
      fluorescence, total carbon-carbonate, and 40-element inductively coupled
      plasma and inductively coupled plasma mass spectrometric analyses.
      Magnetic susceptibilities, converted to estimates of volume-percent
      magnetite were also calculated.  Although magnetite is a minor mineral
      constituent, it is easily measured, and can be positively correlated to
      measurable percentages of important acid-neutralizing minerals, such as
      chlorite and calcite and inversely correlated to NAP indicator minerals
      including pyrite and clay minerals.Ranks were assigned to the samples
      based on ANC quantity in kilograms/ton (kg/ton) calcium carbonate
      equivalent, and ratios of ANC to NAP.  Results show that of all units
      studies Pyroxene Andesite Member of the Silverton Volcanics has highest
      ANC with little to no NAP in either the propylitic or weakly
      sericitically-altered samples.  Samples of the propylitically altered
      Pyroxene Andesite Member also contains the highest mean magnetite
      abundance and therefore, may permit its regional mapping using the
      airborne magnetic and electromagnetic survey data.  Samples from the Burns
      Member of the Silverton Volcanics, in general have a low ANC, high to
      moderate NAP, and in general, contain little to no magnetite.
      Propyllitized Burns Member clasts in talus that formed near the southeast
      Silverton caldera margin in Minnie Gulch; however, have high ANC and low
      NAP.  Samples containing trace to minor quantities pyrite have NAP that
      ranges from non-detectable to 182 kg/ton CaCO3.  Samples with no
      detectable calcite often contain abundant chlorite species (clinochlore
      and chamosite).  Acid titration was performed on a chlorite mineral
      separate comprised mainly of the minerals clinochlore and chamosite,
      collected from a Burns Member lava with a high ANC (second highest ANC of
      all samples studied) and that lacks calcite.  Acid titration results
      indicate that chlorite species have some ANC over a range between pH 4 and
      pH 2.  The calculated ANC of the chlorite mineral separate is 54 kg/ton
      CaCO3 equivalent.  This indicates that samples that lack calcite, where
      chlorite is also abundant could supply some ANC.  This study provides
      information that could be useful to local stakeholders groups and
      federal land managers involved in mine cleanup efforts.  Several samples
      studied have ANC values that exceed the 20 kg/ton CaCO3 equivalent
      necessary for consideration in mine waste remediation.  Data collected for
      the environmental rock properties, NAP and ANC, of Animas River watershed
      rocks could aid in locating rocks that could be suitable for use in
      ongoing mine waste remediation efforts to neutralize acid mine drainage.

    Purpose:
      This point coverage was constructed to identify sample locations for NAP
      and ANC determinations on samples discussed in both a previous study
      (OFR-2005-1433) and the current report (SIR 2008-5063).

    Supplemental_Information:
      This product consists of one vector point coverage.  The
      coverage represents the locations of rock types sampled, and associated
      NAP and ANC rank.

  Time_Period_of_Content:
    Time_Period_Information:
      Single_Date/Time:
        Calendar_Date: 2008
    Currentness_Reference: Publication date

  Status:
    Progress: Complete
    Maintenance_and_Update_Frequency: None planned

  Spatial_Domain:
    Bounding_Coordinates:
      West_Bounding_Coordinate: -107.875
      East_Bounding_Coordinate: -107.5
      North_Bounding_Coordinate: 38.0
      South_Bounding_Coordinate: 37.75

  Keywords:
    Theme:
      Theme_Keyword_Thesaurus: none
      Theme_Keyword: Animas River watershed
      Theme_Keyword: U.S. Geological Survey Minerals Team
      Theme_Keyword: Acid neutralizing capacity
      Theme_Keyword: Net acid production
      Theme_Keyword: Mine waste remediation
      Theme_Keyword: Silverton Volcanics
      Theme_Keyword: Propyllitic alteration
      Theme_Keyword: Tertiary volcanics
      Theme_Keyword: Chlorite

    Place:
      Place_Keyword_Thesaurus:
        U.S. Board on Geographic Names
        (BGN) Geographic Names Information System (GNIS)

      Place_Keyword: USA
      Place_Keyword: Colorado
      Place_Keyword: southwestern Colorado
      Place_Keyword: San Juan County
      Place_Keyword: San Juan Mountains
      Place_Keyword: San Juan National Forest
      Place_Keyword: San Juan volcanic field
      Place_Keyword: Animas River watershed
      Place_Keyword: Ironton
      Place_Keyword: Handies Peak
      Place_Keyword: Ophir
      Place_Keyword: Silverton
      Place_Keyword: Howardsville

  Access_Constraints: None

  Use_Constraints:
    The intended scale of use for these data is 1:24,000.
    Acknowledgment of the U.S. Geological Survey would be
    appreciated in products derived from these data.

  Point_of_Contact:
    Contact_Information:
      Contact_Person_Primary:
        Contact_Person: Douglas B. Yager
        Contact_Organization: U.S. Geological Survey
      Contact_Address:
        Address_Type: mailing address
        Address:
          U.S. Geological Survey, MS 973, PO Box 25046,
          Denver Federal Center
        City: Denver
        State_or_Province: Colorado
        Postal_Code: 80225
        Country: USA
      Contact_Voice_Telephone: (303)236-2487
      Contact_Electronic_Mail_Address: dyager@usgs.gov

  Browse_Graphic:
    Browse_Graphic_File_Name: <http://pubs.usgs.gov/sir/2008/5063
    Browse_Graphic_File_Description:
      link to graphic
      representation of map layout
    Browse_Graphic_File_Type: PDF

  Data_Set_Credit:
    D.B. Yager and M.R. Stanton. D.B. Yager created the vector
    point coverage and accompanying database.

  Native_Data_Set_Environment: ARCINFO 7.2Sun Unix platform, and ArcGIS 9.1

Data_Quality_Information:
  Attribute_Accuracy:
    Attribute_Accuracy_Report:
      Label error tests were performed on the digital coverage
      to ensure that no features are unlabeled.  The attributes have been
      checked for accuracy by comparing tabular data included as part of
      SIR 2008-5063.

  Logical_Consistency_Report: Each point has unique label ids and attribute information.

  Completeness_Report:
    Sampling focused on the Tertiary volcanic rocks in the study area near
    Silverton, Colo.  Most data were collected for the Burns and Pyroxene
    Andesite Members of the Silverton Volcanics.  Other igneous units were
    sampled in reconnaissance only.  Paleozoic and Mesozoic units were
    unsampled.

  Positional_Accuracy:
    Horizontal_Positional_Accuracy:
      Horizontal_Positional_Accuracy_Report:
        The estimated horizontal positional accuracy of sample sites
        is about 3- to 5 meters and is based on the average positional accuracy
        of GPS instruments used for this study.

  Lineage:
    Process_Step:
      Process_Description:
        Sample location data were acquired using PLGR and Garmin GPS units.
        Acid neutralizing capacity attributes were added to the point coverage
        once the were determined in the laboratory.

      Process_Date: 2005

    Process_Step:
      Process_Description:
        GPS data were plotted for positional verification accuracy on USGS
        1:24,000-scale topographic base maps and were then plotted on base
        topographic data that are part of U.S. Geological Survey Professional
        Paper 1651.

      Process_Date: 2005

Spatial_Data_Organization_Information:
  Direct_Spatial_Reference_Method: Vector

Spatial_Reference_Information:
  Horizontal_Coordinate_System_Definition:
    Planar:
      Grid_Coordinate_System:
        Grid_Coordinate_System_Name: Universal Transverse Mercator
        Universal_Transverse_Mercator:
          UTM_Zone_Number: 13
          Transverse_Mercator:
            Scale_Factor_at_Central_Meridian: .9996
            Longitude_of_Central_Meridian: -105.0
            Latitude_of_Projection_Origin: 0.0
            False_Easting: 500000.0
            False_Northing: 0.0
      Planar_Coordinate_Information:
        Planar_Coordinate_Encoding_Method: coordinate pair
        Coordinate_Representation:
          Abscissa_Resolution: 65
          Ordinate_Resolution: 65
        Planar_Distance_Units: decimal degrees
    Geodetic_Model:
      Horizontal_Datum_Name: North American Datum of 1927
      Ellipsoid_Name: Clarke 1866
      Semi-major_Axis: 6378206.4
      Denominator_of_Flattening_Ratio: 294.98

Entity_and_Attribute_Information:
  Overview_Description:
    Entity_and_Attribute_Overview:
      DATABASE STRUCTURE--The database structure of the point coverage is
      composed of the following INFO and other attribute fields.

      INFO attribute items.
      AREA
      PERIMETER
      ANCUTM#
      ANCUTM ID

      Other attribute items.
      FIELD_NUM
      LONGITUDE
      LATITUDE
      ANC_RANK
      CACO3_PH2
      NAP
      UNIT
      SITE_DESC
      ROCK_TYPE

      FIELD_NUM is the unique alphanumeric field number identifier for a sample
      site. LONGITUDE and LATITUDE are the coordinates for the sample
      site in decimal degrees.  ANC_RANK is the acid neutralizing capacity rank
      with 1 having the highest ANC and subsequent higher numbers having
      progressively lower ANC.  CACO3_PH2 indicates the ANC of a sample titrated
      to pH 2, calculated in terms of calcium carbonate equivalent units. NAP is 
      net acid production. UNIT is geologic formation.  SITE_DESC is
      the locality description of the site.  ROCK_TYPE describes the
      characteristics of the sample collected, whether an altered lava flow,
      volcaniclastic sedimentary rock, or in one instance, colluvium.

    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 address
        Address: USGS Information Services
        Address: Box 25286
        City: Denver
        State_or_Province: Colorado
        Postal_Code: 80225
        Country: USA
      Contact_Voice_Telephone: 1-888-ASK-USGS

  Resource_Description: Scientific Investigations Report 2008-5063
  Distribution_Liability:
    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 U.S. Government or any agency thereof.
    These files have been approved for release and publication by the Director of the USGS.  Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review.  Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.
    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 information product, for the most part, is in the public domain, it also contains copyrighted materials as noted in the text.  Permission to reproduce copyrighted items for other than personal use must be secured from the copyright owner.
    Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.  The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and/or contained herein.

  Standard_Order_Process:
    Digital_Form:
      Digital_Transfer_Information:
        Format_Name:
          ArcInfo interchange file and ArcInfo
          shapefile formats
        Format_Version_Number: ArcInfo version 7.2.1 and ArcGIS version 9.1
        File_Decompression_Technique:
          .tar.gz - UNIX gzip-compressed TAR file - use GNU zip
          and TAR to extract
          .ZIP - Windows ZIP archive - use Winzip, PKZip, or
          similar to extract
      Digital_Transfer_Option:
        Online_Option:
          Computer_Contact_Information:
            Network_Address:
              Network_Resource_Name: <http://pub.usgs.gov/sir/2008/5063/
    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: Box 25286
        City: Denver
        State_or_Province: CO
        Postal_Code: 80225
        Country: United States
      Contact_Voice_Telephone: 1-888-ASK-USGS
  Resource_Description: SIR 2008-5063

  Distribution_Liability:
    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 U.S. Government or any agency thereof.
    These files have been approved for release and publication by the Director of the USGS.  Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review.  Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.
    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 information product, for the most part, is in the public domain, it also contains copyrighted materials as noted in the text.  Permission to reproduce copyrighted items for other than personal use must be secured from the copyright owner.
    Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.  The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and/or contained herein.

  Standard_Order_Process:
    Non-digital_Form: Available as one printed book with 1 map plate in pocket
    Fees:
      For current prices please see
      <http://store.usgs.gov/mod/order.html
Metadata_Reference_Information:
  Metadata_Date: 20030312
  Metadata_Contact:
    Contact_Information:
      Contact_Person_Primary:
        Contact_Person: Douglas B. Yager
        Contact_Organization: U.S. Geological Survey
      Contact_Address:
        Address_Type: mailing address
        Address: Box 25046
        Address: Denver Federal Center, MS973
        City: Denver
        State_or_Province: Colorado
        Postal_Code: 80225
        Country: USA
      Contact_Voice_Telephone: (303) 236-2487
      Contact_Electronic_Mail_Address: dyager@usgs.gov

  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