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