Digital map of hydrothermal alteration type, key mineral groups, and green vegetation of the northwestern United States derived from automated analysis of ASTER satellite data

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Frequently anticipated questions:


What does this data set describe?

Title:
Digital map of hydrothermal alteration type, key mineral groups, and green vegetation of the northwestern United States derived from automated analysis of ASTER satellite data
Abstract:
Mineral groups identified through automated analysis of remote sensing data acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) were used to generate a map showing the type and spatial distribution of hydrothermal alteration, other exposed mineral groups, and green vegetation across the northwestern conterminous United States. Boolean algebra was used to combine mineral groups identified through analysis of visible, near-infrared, and shortwave-infrared ASTER data into attributed alteration types and mineral classes based on common mineralogical definitions of such types and the minerals present within the mineral groups. Alteration types modeled in this way can be stratified relative to acid producing and neutralizing potential to aid in geoenvironmental watershed studies. This mapping was performed in support of multidisciplinary studies involving the predictive modeling of mineral deposit occurrence and geochemical environments at watershed to regional scales. These studies seek to determine the relative effects of mining and non-anthropogenic hydrothermal alteration on watershed surface water geochemistry and faunal populations. The presence or absence of hydrothermally-altered rocks and (or) specific mineral groups can be used to model the favorability of occurrence of certain types of mineral deposits, and aid in the delineation of permissive tracts for these deposits. These data were used as a data source for the U.S. Geological Survey (USGS) Sagebrush Mineral-Resource Assessment (SaMiRA). This map, in ERDAS Imagine (.img) format, has been attributed by pixel value with material identification data that can be queried in most image processing and GIS software packages. Three files are included with this product: file with .img extension contains thematic image attributes and geographic projection data, file with .ige extension contains the raster data, and the file with .rrd extension includes pyramid data for fast display.
Supplemental_Information:
These data represent version 2 of the mosaic of the northwestern U.S. produced on June 11, 2013 using algorithm build AA61.
  1. How might this data set be cited?
    Rockwell, Barnaby W., and Bonham, Lindsey C., 2017, Digital map of hydrothermal alteration type, key mineral groups, and green vegetation of the northwestern United States derived from automated analysis of ASTER satellite data: USGS data release 10.5066/F7CR5RK7, U.S. Geological Survey, Denver, CO.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -125.119620923
    East_Bounding_Coordinate: -98.9894527256
    North_Bounding_Coordinate: 49.5956281265
    South_Bounding_Coordinate: 40.7688227906
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 01-May-2000
    Ending_Date: 01-Oct-2007
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: Raster digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Raster data set. It contains the following raster data types:
      • Dimensions 32699 x 68458 x 1, type Grid Cell
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000269941139971. Longitudes are given to the nearest 0.000381696342245. Latitude and longitude values are specified in Decimal seconds. The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    aster_northwest_aa61_v2_6-11-13.img.vat
    Table containing attribute information associated with the data set. (Source: Producer defined)
    OID
    Internal feature number. (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Value
    Internal digital number (Source: Author)
    Range of values
    Minimum:0
    Maximum:255
    Count
    Value frequency count (Source: Author)
    Range of values
    Minimum:0
    Maximum:454432322
    Red
    Red value of color table (Source: Author)
    Range of values
    Minimum:0
    Maximum:1
    Green
    Green value of color table (Source: Author)
    Range of values
    Minimum:0
    Maximum:1
    Blue
    Blue value of color table (Source: Author)
    Range of values
    Minimum:0
    Maximum:1
    Opacity
    Opacity of value - denotes whether or not a material ID has been assigned (Source: Author)
    Range of values
    Minimum:0
    Maximum:1
    MaterialID
    Material(s) identified in a pixel. Enumerated_Domain_Values correspond to the internal digital number values of the "Value" attribute. (Source: Author)
    ValueDefinition
    0No materials classified
    1Minor ferric iron
    2Major ferric iron
    3Advanced argillic +/- ferric iron
    4Argillic (kandite clay +/- sericite +/- smectite) +/- minor advanced argillic
    5Sericite and (or) smectite
    6Carbonate-propylitic
    7Dolomite (may include Mg/Fe-OH phyllosilicates or epidote in igneous and metamorphic terranes)
    8Jarosite +/- sericite +/- smectite, or hydrous silica + ferric iron
    9Hydrous silica
    10Sericite + chlorite or Fe/Mg sericite
    11Argillic + ferric iron or weathered phyllic +/- minor advanced argillic
    12Sericite and (or) smectite + ferric iron (may include fresh phyllic)
    13Carbonate-propylitic + sericite and (or) smectite
    14Green vegetation
    15Carbonate-propylitic + ferric iron
    16Sericite + chlorite or Fe/Mg sericite + ferric iron
    17Carbonate-propylitic + sericite and (or) smectite + ferric iron
    18Dolomite + ferric iron (may include Mg/Fe-OH phyllosilicates or epidote in igneous and metamorphic terranes)
    19Carbonate-propylitic +/- hydrous silica (may include some dolomite)
    20Carbonate-propylitic +/- hydrous silica + ferric iron (may include some dolomite)
    21Ferrous or coarse-grained ferric iron (may include oxidized basalts, fire ash, some moist soils, and any blue/green rocks)
    22Carbonate-propylitic + ferrous or coarse-grained ferric iron
    23Dolomite + ferrous or coarse-grained ferric iron (may include Mg/Fe-OH phyllosilicates or epidote in igneous and metamorphic terranes)
    45Dry vegetation in fallow agricultural fields - deep 2.17 and 2.20 micron absorption (identified as argillic, class 4, yellow)
    46Dry, yellow/brown veg. in fallow agricultural fields - 2.17 and 2.20 micron absorption (identified as argillic + Fe, class 11, orange)
    47Dry vegetation in fallow agricultural fields - deep 2.17 micron absorption (identified as advanced argilllic, class 3, red)
    48No data (clouds, cloud shadow, smoke, haze, data errors)
    49Semi-corrupted SWIR band 5: identified advanced argillic and argillic alteration may be unreliable
    50Semi-corrupted SWIR band 7: identified dolomite, hydrous silica, and jarosite may be unreliable
    Entity_and_Attribute_Overview:
    Results of merging of mineral groups identified through automated analysis of ASTER multispectral data. The digital number (DN) values in this image have been attributed by modeled alteration type, mineral group, or green vegetation as shown in the following table. Each DN value corresponds to a particular color in the included color table. All pixels identified as a particular alteration type or mineral group have been assigned a single, discrete color. Pixels with a DN value of zero indicate either that no materials were identified or that no input spectral data were available. There are no DN data values in the range of 24-44 or greater than 50.

    Value  Count Red   Green Blue  Opacity MaterialID
     1  18455527 1     0.749 0.8   1       Minor ferric iron
     2    719220 0.929 0.51  0.929 1       Major ferric iron
     3   2595880 1     0     0     1       Advanced argillic +/- ferric iron
     4   2137365 1     1     0     1       Argillic (kandite clay +/- sericite +/- smectite) +/- minor advanced argillic
     5  78094642 0.129 0.788 0.718 1       Sericite and (or) smectite
     6   2140915 0     1     0     1       Carbonate-propylitic
     7    898039 0     0     1     1       Dolomite (may include Mg/Fe-OH phyllosilicates or epidote in igneous and metamorphic terranes)
     8    203441 1     0     1     1       Jarosite +/- sericite +/- smectite, or hydrous silica + ferric iron
     9   2549741 0.588 0.247 0.8   1       Hydrous silica
    10   1397612 0.298 0.62  0.42  1       Sericite + chlorite or Fe/Mg sericite
    11    916940 1     0.647 0     1       Argillic + ferric iron or weathered phyllic +/- minor advanced argillic
    12  32659247 0     1     1     1       Sericite and (or) smectite + ferric iron (may include fresh phyllic)
    13    576976 0.82  0.71  0.549 1       Carbonate-propylitic + sericite and (or) smectite
    14 454432322 0     0.388 0     1       Green vegetation
    15   1328216 0.647 0.157 0.157 1       Carbonate-propylitic + ferric iron
    16    252995 0.62  0.749 0.129 1       Sericite + chlorite or Fe/Mg sericite + ferric iron
    17   5395824 0.859 0.557 0.486 1       Carbonate-propylitic + sericite and (or) smectite + ferric iron
    18    140119 0.576 0.737 0.878 1       Dolomite + ferric iron (may include Mg/Fe-OH phyllosilicates or epidote in igneous and metamorphic terranes)
    19      9170 0.639 0.6   0.808 1       Carbonate-propylitic +/- hydrous silica (may include some dolomite)
    20       555 0.71  0.576 0.808 1       Carbonate-propylitic +/- hydrous silica + ferric iron (may include some dolomite)
    21  15910210 0.357 0.447 0.498 1       Ferrous or coarse-grained ferric iron (may include oxidized basalts, fire ash, some moist soils, and any blue/green rocks)
    22    123166 0.486 0.486 0.188 1       Carbonate-propylitic + ferrous or coarse-grained ferric iron
    23     50824 0.22  0.486 0.737 1       Dolomite + ferrous or coarse-grained ferric iron (may include Mg/Fe-OH phyllosilicates or epidote in igneous and metamorphic terranes)
    24         0 0     0     0     1
    25         0 0     0     0     1
    26         0 0     0     0     1
    27         0 0     0     0     1
    28         0 0     0     0     1
    29         0 0     0     0     1
    30         0 0     0     0     1
    31         0 0     0     0     1
    32         0 0     0     0     1
    33         0 0     0     0     1
    34         0 0     0     0     1
    35         0 0     0     0     1
    36         0 0     0     0     1
    37         0 0     0     0     1
    38         0 0     0     0     1
    39         0 0     0     0     1
    40         0 0     0     0     1
    41         0 0     0     0     1
    42         0 0     0     0     1
    43         0 0     0     0     1
    44         0 0     0     0     1
    45    176399 0.4   0.2   0.086 1       Dry vegetation in fallow agricultural fields - deep 2.17 and 2.20 micron absorption (identified as argillic, class 4, yellow)
    46    159482 0.529 0.239 0.11  1       Dry, yellow/brown veg. in fallow agricultural fields - 2.17 and 2.20 micron absorption (identified as argillic + Fe, class 11, orange)
    47    451561 0.627 0.318 0.176 1       Dry vegetation in fallow agricultural fields - deep 2.17 micron absorption (identified as advanced argilllic, class 3, red)
    48  21435017 0.149 0.149 0.149 1       No data (clouds, cloud shadow, smoke, haze, data errors)
    49 103303300 0.2   0.2   0.2   1       Semi-corrupted SWIR band 5: identified advanced argillic and argillic alteration may be unreliable
    50 107136639 0.247 0.247 0.247 1       Semi-corrupted SWIR band 7: identified dolomite, hydrous silica, and jarosite may be unreliable
    
    Raster filename: aster_northwest_aa61_v2_6-11-13.img
    Entity_and_Attribute_Detail_Citation: https://pubs.usgs.gov/sim/3190/

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Rockwell, Barnaby W.
    • Bonham, Lindsey C.
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey
    Attn: Barnaby W. Rockwell
    Research Geophysicist
    Box 25046, Mail Stop 973
    Denver, Colorado
    US

    303-236-1851 (voice)

Why was the data set created?

The purpose of the image is to display the spatial distribution of hydrothermal alteration types, key mineral groups, and green vegetation modeled by automated analysis of ASTER satellite remote sensing data covering the northwestern United States.

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: 2013 (process 1 of 1)
    Methods used to derive these data are described in https://pubs.usgs.gov/sim/3190/contents/SIM3190_pam.pdf .
  3. What similar or related data should the user be aware of?
    Rockwell, Barnaby W., 20110101, Description and validation of an automated methodology for mapping mineralogy, vegetation, and hydrothermal alteration type from ASTER satellite imagery with examples from the san juan mountains, Colorado: Scientific Investigations Map 3190, U.S. Geological Survey, Denver, CO.

    Online Links:


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

  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  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
Use_Constraints:
Acknowledgement of the U.S. Geological Survey would be appreciated in products derived from these data. Data have been checked to ensure the accuracy of the data. If any errors are detected, please notify the originating office. The U.S. Geological Survey strongly recommends that careful attention be paid to the metadata file associated with these data. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in ArcGIS and ERDAS Imagine formats, this metadata file may include some terminology specific to those software packages.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - ScienceBase
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO
    US

    1-888-ASK-USGS (1-888-275-8747) (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set?
  3. What legal disclaimers am I supposed to read?
    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. This database, identified as USGS Data Release 10.5066/F7CR5RK7, has been approved for release and publication by 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. 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.
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: Raster Digital Data Set (version 11.0.1) Size: 9.04
      Network links: https://doi.org/10.5066/F7CR5RK7
    • Cost to order the data: none


Who wrote the metadata?

Dates:
Last modified: 28-Jan-2019
Metadata author:
Peter N Schweitzer
USGS Eastern Mineral and Environmental Resources Science Center
Geologist
12201 Sunrise Valley Drive
Reston, VA
USA

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

This page is <https://mrdata.usgs.gov/metadata/aster_northwest_aa61_v2_6-11-13.faq.html>
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