Ferricrete, manganocrete, and bog iron occurrences with selected sedge bogs and active iron bogs and springs in the upper Animas River watershed, San Juan County, Colorado

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Frequently anticipated questions:

What does this data set describe?

Ferricrete, manganocrete, and bog iron occurrences with selected sedge bogs and active iron bogs and springs in the upper Animas River watershed, San Juan County, Colorado
During 1996 to 2000, the Bureau of Land Management, National Park Service, Environmental Protection Agency, United States Department of Agriculture (USDA) Forest Service, and the U.S. Geological Survey (USGS) developed a coordinated strategy to (1) study the environmental effects of historical mining on Federal lands, and (2) remediate contaminated sites that have the greatest impact on water quality and ecosystem health. This dataset provides information that contributes to these overall objectives and is part of the USGS Abandoned Mine Lands Initiative. Data presented here represent ferricrete occurrences and selected iron bogs and springs in the upper Animas River watershed in San Juan County near Silverton, Colorado. Ferricretes (stratified iron and manganese oxyhydroxide-cemented sedimentary deposits) are one indicator of the geochemical baseline conditions as well as the effect that weathering of mineralized rocks had on water quality in the Animas River watershed prior to mining. Logs and wood fragments preserved in several ferricretes in the upper Animas River watershed, collected primarily along streams, yield radiocarbon ages of modern to 9,580 years B.P. (P.L. Verplanck, D.B. Yager, and S.E. Church, work in progress). The presence of ferricrete deposits along the current stream courses indicates that climate and physiography of the Animas River watershed have been relatively constant throughout the Holocene and that weathering processes have been ongoing for thousands of years prior to historical mining activities. Thus, by knowing where ferricrete is preserved in the watershed today, land-management agencies have an indication of (1) where metal precipitation from weathering of altered rocks has occurred in the past, and (2) where this process is ongoing and may confound remediation efforts.
These data are included as two coverages-a ferricrete coverage and a bogs and springs coverage. The coverages are included in ArcInfo shapefile and ArcInfo interchange file format.
This product consists of two vector polygon coverages. The coverages include a ferricrete coverage and an iron bogs, sedge bogs, and springs coverage.
  1. How might this data set be cited?
    Yager, Douglas B., Church, Stanley E., Verplanck, Philip L., and Wirt, Laurie, 2003, Ferricrete, manganocrete, and bog iron occurrences with selected sedge bogs and active iron bogs and springs in the upper Animas River watershed, San Juan County, Colorado: U.S. Geological Survey Miscellaneous Field Studies Map MF-2406, U.S. Geological Survey, Denver, Colorado.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -107.7775
    East_Bounding_Coordinate: -107.5581
    North_Bounding_Coordinate: 37.9258
    South_Bounding_Coordinate: 37.7983
  3. What does it look like?
    http://pubs.usgs.gov/mf/2003/mf-2406/mf-2406.gif (GIF)
    Reduced-size image of the map sheet, 350x275 pixels, 63k bytes
    http://pubs.usgs.gov/mf/2003/mf-2406/mf-2406.pdf (PDF)
    Printable representation of map layout, 90 megabytes
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2003
    Publication date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: map
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Vector data set.
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      UTM_Zone_Number: 13
      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 coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 65
      Ordinates (y-coordinates) are specified to the nearest 65
      Planar coordinates are specified in meters
      The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.4.
      The flattening of the ellipsoid used is 1/294.98.
  7. How does the data set describe geographic features?
    DATABASE STRUCTURE--The database structure of the map consists of two coverages. These coverages include the "FRCT" and the "BOG" coverage. They have the following INFO attribute items.
    The FRCT coverage contains all contact lines and label points for each polygon related to the ferricrete data, and the BOG coverage contains all contact lines and label points for each polygon related to the bogs and springs data. The FRCT.PAT and BOG.PAT INFO files have the non-common attribute field for DEP_TYPE. DEP_TYPE is a text field that describes each deposit type polygon and each poly line. Two shapefiles each comprise the ferricrete and bogs and springs features. The ferricrete poly and arc features are included in the "frct.shp" and "frcta.shp" shapefiles, respectively. The bog and spring features are included in the bog.shp and boga.shp shapefiles, respectively.
    The following detailed overview discusses the non-common attribute DEP_TYPE included in the FRCT and the BOG coverages that comprise the ferricrete and iron bogs and springs coverages and the frct.shp, frcta.shp, bog.shp, and boga.shp shapefiles.
    The INFO files FRCT.PAT and FRCT.AAT have populated attribute fields for item DEP_TYPE and SYMBOL. The INFO items DEP_TYPE and SYMBOL are populated with corresponding text that identifies each unique mapped deposit type and its corresponding map symbol. These ferricrete DEP_TYPE and corresponding SYMBOL attributes are as follows.
    af   Alluvial ferricrete
    cf   Colluvial ferricrete
    uf   Undifferentiated ferricrete
    mncf Colluvial manganocrete
    mnaf Alluvial manganocrete
    tf   Transitional colluvial manganocrete and ferricrete
    bi   Bog iron
    The INFO files BOG.PAT and BOG.AAT have populated attribute fields for item DEP_TYPE and SYMBOL. The INFO items DEP_TYPE and SYMBOL are populated with corresponding text that identifies each unique mapped deposit type and its corresponding map symbol. These bog and spring DEP_TYPE and corresponding SYMBOL attributes are as follows.
    sb  Sedge bog
    spi Iron spring
    ib  Iron bog
    ub  Undifferentiated bog
    Entity_and_Attribute_Detail_Citation: http://pubs.usgs.gov/mf/2003/mf-2406/mf-2406_508.pdf

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Douglas B. Yager
    • Stanley E. Church
    • Philip L. Verplanck
    • Laurie Wirt
  2. Who also contributed to the data set?
    D.B. Yager; S.E. Church; P.L. Verplanck; and Laurie Wirt mapped the ferricrete and bog occurrences. T.C. Sole assisted in digitally compiling data along Cement Creek. D.B. Yager compiled all ferricrete and bog data and created the ArcInfo coverages. Preliminary ferricrete maps were provided by T.J. Casadevall and D.J. Sofield, which were used to guide detailed mapping efforts.
  3. To whom should users address questions about the data?
    Douglas B. Yager
    U.S. Geological Survey
    U.S. Geological Survey, MS 973, PO Box 25046,
    Denver Federal Center
    Denver, Colorado

    (303)236-2487 (voice)

Why was the data set created?

This map was constructed to identify ferricrete occurrences in the upper Animas River watershed. Ferricrete is one indicator of pyrite oxidation and acid rock drainage that have been ongoing in this region since the late Pleistocene. The mapping of ferricrete occurrences increases our understanding of the geochemical baseline conditions that existed in the Animas River watershed prior to mining. The digital GIS coverages provided may be used to evaluate the spatial relationships among iron-rich ground water, ferricrete occurrences,structure, and alteration assemblages.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 1996 (process 1 of 3)
    1:5,600-scale color enlargements of 1973 USDA Forest Service aerial photographs were used to map ferricrete and bog occurrences in the field along Cement Creek basin. All other field mapping was accomplished on 1:24,000-scale USGS topographic maps. The 1:24,000-scale data were transferred by hand to USGS topographic greenline base mylar maps and later scanned and converted to ArcInfo coverages. Cement Creek data, at creek level, were digitally compiled by the on-screen digitizing method, and using 1-m resolution digital ortho quadrangles as a backdrop image.
    Date: 1996 (process 2 of 3)
    Drafted linework was scanned with a scan resolution of 400 dpi. ArcInfo commands, IMAGEGRID and GRIDLINE, were used for raster to vector conversion. The vector cover produced was projected first with use of the ArcInfo TRANSFORM command. The vector coverage was TRANSFORMED into an empty TICCOV derived from the vector coverage with geographic coordinate-defined corner tics. Once transformed, the coverage was projected using ArcInfo's project command. Label errors were determined and corrected and the coverage topology was established.
    Date: 12-Mar-2003 (process 3 of 3)
    Creation of original metadata record Person who carried out this activity:
    Douglas B. Yager
    U.S. Geological Survey
    Box 25046
    Denver, Colorado

    (303) 236-2487 (voice)
  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    100 percent of ferricrete and iron bog and spring occurrences and unit attributes were compared to paper maps for accuracy when compiled and digitized. A quantitative assessment of attribute accuracy was not attempted. Label error tests were performed on digital coverages to ensure that no features are unlabeled. The attributes have been checked by the authors' unpublished field maps, and preliminary draft versions of the maps.
  2. How accurate are the geographic locations?
    The estimated horizontal positional accuracy of the data is about 12 meters in other mapped locations. All data used from published and unpublished digital sources are limited by the accuracy of these data. Attempts were made to verify the accuracy of these data by comparison to published topographic data and overlap with other digital data.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Completeness of the data is a function of the scale of source maps used when compiling data from 1:24,000-scale field sheets for the majority of the watershed area, and 1:5,600-scale aerial photography along Cement Creek only. Mapping in the upper Animas River subbasin region near Eureka and Hematite Gulch and surrounding subbasins and in the regions southeast of the Animas River near Arrastra Gulch and Cunningham Creek subbasins was done in reconnaissance only.
  5. How consistent are the relationships among the observations, including topology?

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None
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.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S.Geological Survey
    USGS Information Services
    Denver, CO
    United States

    1-888-ASK-USGS (voice)
  2. What's the catalog number I need to order this data set? USGS Miscellaneous Field Studies Map MF-2406
  3. What legal disclaimers am I supposed to read?
    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.
  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 13-Jun-2016
Metadata author:
Peter N Schweitzer
USGS Midwest Area
Collection manager, USGS Geoscience Data Clearinghouse, http://geo-nsdi.er.usgs.gov/
Mail Stop 954
12201 Sunrise Valley Dr
Reston, VA

703-648-6533 (voice)
703-648-6252 (FAX)
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://geo-nsdi.er.usgs.gov/metadata/map-mf/2406/metadata.faq.html>
Generated by mp version 2.9.48 on Tue Jul 03 20:05:18 2018