Identification_Information: Citation: Citation_Information: Originator: Douglas B. Yager Publication_Date: 2005 Title: Net Acid Production, Acid Neutralizing Capacity, and Associated Geophysical, 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 Open File Report Issue_Identification: OFR-2005-1433 Publication_Information: Publication_Place: Denver, Colorado Publisher: U.S. Geological Survey Online_Linkage: Description: Abstract: This point coverage, "anc_rank", presents results from laboratory studies involving the net acid production (NAP), acid neutralizing capacity (ANC), and magnetic mineralogy of thirty-four samples collected in the Upper Animas River watershed near Silverton, Colo., during the summer of 2003. 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 pyroxide (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 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 the 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 (over 8 volume percent) 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. Samples containing pyrite (? 1 weight percent) have NAP that ranges from non-detectable to 39 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 prove 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. Purpose: This point coverage was constructed to identify sample locations for NAP and ANC discussed in the accompanying OFR-2005-1433 and provide associated attribute information for each sample site. Supplemental_Information: This product consists of one vector point coverage. The coverage represents the locations of rock types sampled, and associated acid neutralizing capacity rank. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2005 Currentness_Reference: Publication date Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -107.778340 East_Bounding_Coordinate: -107.558240 North_Bounding_Coordinate: 37.933390 South_Bounding_Coordinate: 37.798000 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: Animas River watershed Place_Keyword: southwestern Colorado Place_Keyword: Silverton Place_Keyword: San Juan County Place_Keyword: San Juan volcanic field Place_Keyword: San Juan Mountains Place_Keyword: San Juan National Forest 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: Browse_Graphic_File_Description: link to graphic representation of map layout Browse_Graphic_File_Type: PDF Data_Set_Credit: D.B. Yager; A.E. McCafferty, M.R. Stanton, S.F. Diehl, R.L. Driscoll, D.L. Fey, and S.J. Sutley were involved in various analytical phases of this report, D.B. Yager created the vector point coverage and accompanying database attributes that correspond to data in the Open-File report. 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 OFR-2005-1433. Logical_Consistency_Report: Each point has unique label id’s 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: 2003 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 (in press) Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Geographic 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 ANC_RANK# ANC_RANK –ID Other attribute items. FIELD_NUM ANC_RANK UNIT LONGITUDE LATITUDE SITE_DESC ROCK_TYPE CACO3_PH3 CACO3_PH2 The ANC_RANK coverage contains all point featurews related to the samples collected as part of the acid neutralizing capacity study presented in Open-File report 2006. FIELD_NUM is the unique alphanumeric field number identifier for a sample site. ANC_RANK is the acid neutralizing capacity rank from 1 having the highest ANC. LONGITUDE and LATITUDE are the coordinates for the sample site in decimal degrees. 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. CACO3_PH3 and CACO3_PH2 indicate the calculated amount (based on acid titration to pH3 and pH2 respectively)of ANC calcium carbonate equivalent in kilograms per ton. Blank or 0 values in the field CACO3_PH3 indicate that a calculation was either not determined for this pH interval or a sample had minimal to no ANC when titrated to pH 3 (see details in Open-File report 2006) 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: Open-File Report 2005-1433 (Map-on-Demand) Distribution_Liability: none Standard_Order_Process: Non-digital_Form: Available as one printed sheet and a 20-page report. Order from USGS at address above or see for more ordering information. Fees: For current prices see Distribution_Liability: The U.S. Geological Survey (USGS) provides these geographic data "as is". The USGS makes no guarantee or warranty concerning the accuracy of information contained in the geographic data. The USGS further makes no warranties, either expressed or implied, as to any other matter whatsoever, including, without limitation, the condition of the product, or its fitness for any particular purpose. The burden for determining fitness for use lies entirely with the user. Although these data have been processed successfully on computers at the USGS, no warranty, expressed or implied, is made by the USGS regarding the use of these data on any other system, nor does the fact of distribution constitute or imply any such warranty. Any use of trade names is for descriptive purposes only and does not imply endorsement by the U.S. Government. This metadata has not been reviewed for geologic nomenclature. 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: 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: MF-2406 (Map-on-Demand) Distribution_Liability: none Standard_Order_Process: Non-digital_Form: Available online at: http://infotrek.er.usgs.gov/pubs/> for more ordering information. Fees: For current prices please see 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