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Preliminary digital map of cryptocrystalline occurrences in northern Nevada: rkhnd (ArcView shapefile) and rkhnd_crypto (ArcInfo point coverage)

Metadata also available as - [Outline] - [Parseable text] - [DIF]

Frequently-anticipated questions:

What does this data set describe?

Title:
Preliminary digital map of cryptocrystalline occurrences in northern Nevada: rkhnd (ArcView shapefile) and rkhnd_crypto (ArcInfo point coverage)
Abstract:
A polygon Arcview shapefile of northern Nevada cryptocrystalline occurrences derived from Nevada rockhound guides and converted to a coverage.
Supplemental_Information:
The primary focus was potential raw material sites for tools made by native northern Nevadans. Archaeologists routinely rely on pottery and projectile points for dating techniques. Since basketry was more appropriate for the nomadic lifestyle of the native northern Nevadans, the major dating device for the Great Basin archaeological sites has been the projectile point. Preliminary investigation of the types of raw materials used for tool making by indigenous people of Northern Nevada led to decisions regarding the kind of occurrences considered to be cryptocrystalline for this spatial data set. The rockhound sites were descriptive and not based in a coordinate system. The ArcView distance-measuring tool was used to locate the sites in creating the ArcView 3.0 polygon theme, rkhnd.shp. Eighty-two cryptocrystalline sites were spatially referenced using Nevada 1:100,000 scale digital raster graphic (DRG) maps in UTM projection as background images (Nevada Bureau of Mines and Geology, 1996). Sites were located by measuring described distances and directions along roads and marking with polygon shapes. The size of the polygon represents the distributed or scattered area of the cryptocrystalline material, not the amount of material. The smooth, symmetrical (rather than irregular) shape of the polygon reflects the lack of point-to-point accuracy resulting from the location descriptions. A REFERENCE field numerically codes location accuracy in the polygon theme table, rkhnd.dbf. The polygon TYPE field categorizes the cryptocrystalline material for each rockhound site, and attribute color-coding corresponds to the TYPE field in the point theme table. A MRDS point theme and rockhound polygon theme were combined with an ARC/INFO coverage of Nevada county boundaries and an ArcView 3.0 layout was designed at 1:750,000 scale in UTM Zone 11 map projection. An additional ARC/INFO coverage of northern Nevada roads was used to create the digital preliminary map of northern Nevada cryptocrystalline occurrences.
  1. How should this data set be cited?

    Moyer, Lorre A., 1999, Preliminary digital map of cryptocrystalline occurrences in northern Nevada: rkhnd (ArcView shapefile) and rkhnd_crypto (ArcInfo point coverage): U.S. Geological Survey Open-File Report 99-523, U.S. Geological Survey, Spokane, Washington.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -120.0252
    East_Bounding_Coordinate: -114.4140
    North_Bounding_Coordinate: 41.9792
    South_Bounding_Coordinate: 39.0080

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Calendar_Date: 1975
    Currentness_Reference: Publication dates of rockhound guide sources

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: Digital

  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. It contains the following vector data types (SDTS terminology):

      • GT-polygon composed of chains (82)

    2. What coordinate system is used to represent geographic features?

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 11
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -117
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000
      False_Northing: 0.0

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 200
      Ordinates (y-coordinates) are specified to the nearest 200
      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.

      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: National Geodetic Vertical Datum of 1929
      Altitude_Encoding_Method: Implicit coordinate
      Depth_System_Definition:

  7. How does the data set describe geographic features?

    rkhnd.dbf
    Shapefile attribute table

    TYPE
    Cryptocrystalline occurrence type (character)

    ValueDefinition
    chalcedony 
    cutting material 
    jasper 
    obsidian 
    opal 

    SUBTYPE
    Cryptocrystalline occurrence subtype (character)

    ValueDefinition
    agate 
    Apache tears 
    onyx 
    chalcedony 
    chert 
    cinnabar 
    fire opal 
    jasper 
    obsidian 
    opal 
    opalite 
    petrified wood 
    precious opal 
    wood (petrified wood) 

    LOCATION
    Location accuracy estimation (integer)

    ValueDefinition
    1reasonably accurate
    2general area
    3vague
    4inaccurate

    REFERENCE
    Sources for rockhound site locations (integer)

    ValueDefinition
    1Rockhound's Map of Nevada
    2Gem Trails of Nevada
    3Nevada-Utah Gem Atlas
    4Where to Find Gold and Gems in Nevada

    SITE_NAME
    Site name (character)

    QUADRANGLE
    100k quadrangle map name (character) (Source: NBMG, 1996, Nevada DRG maps on CD-ROM)

    Entity_and_Attribute_Overview:
    The following attributes were extracted from the MRDS database and their values (for the appropriate locations) included in mrds.dbf and mrds_crypto.pat of USGS Open-File Report 99-523:
    RECORD_NO REPORTER REP_DATE REP_AFFIL UPDATER UPD_DATE UPD_AFFIL SITE SYNONYM DISTRICT REC_TYPE COUNTY STATE_CODE COUNTRY_CD QUAD QUAD1 LATITUDE LONGITUDE COMMODS PROD STATUS OWNER OPERATOR DEP_TYPE DEP_FORM DEP_SIZE SURF_UNDG HR_TYPE HR_AGE AGE_OF_MIN IG_RK_TYPE IG_RK_AGE ORE_CTRL TECTONICS ALTERATION CONCENTRAT ORE_MINS NONORE_MIN COMMENTS PROD1 PROD2 PROD3 CUM_ PROD1 CUM_PROD2 CUM_PROD3 PR_COMMENT RESERVES1 RESERVES2 RESERVES3 RESV_COM REF1 REF2 REF3 REF4 REF5 STATE_NAME COUNTRY_NM MODEL_NAME MODEL_NUM
    Entity_and_Attribute_Detail_Citation:
    Mineral Resources Data System metadata at <http://geo-nsdi.er.usgs.gov/metadata/digital-data/20/metadata.met>
    mrds data row
    Fields extracted from MRDS attributes for this data set, with one additional field.

    TYPE
    Cryptocrystalline type

    ValueDefinition
    chalcedony 
    chert 
    jasper 
    opal 
    silica 

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

    Katherine Connors and Gary Raines of the USGS, and Ron Hess of the Nevada Bureau of Mines and Geology assisted in the direction and creation of this data set.

  3. To whom should users address questions about the data?

    U.S. Geological Survey, Reno Field Office
    c/o Lorre A. Moyer
    Geologist
    USGS C/O Mackay School of Mines MS-176, University of Nevada
    Reno, Nevada 89557
    USA

    775-784-5552 (voice)
    775-784-5079 (FAX)
    lorre@usgs.gov

    Hours_of_Service: 800-1600 PT

Why was the data set created?

The polygon shapefile was combined with a point shapefile derived from the U.S. Geological Survey's Mineral Resources Data System (MRDS) to create a preliminary digital map of cryptocrystalline occurrences of northern Nevada. The original intent was to identify potential sources of raw materials for tools used by indigenous people of northern Nevada. The dataset was created to assist government agencies and others in making resource management decisions using geographic information systems (GIS). Uses of the spatial data set include, but are not limited to, natural and cultural resource management, interdisciplinary activities, recreational rockhounding, and gold exploration.

How was the data set created?

  1. From what previous works were the data drawn?

    Johnson, 1978 (source 1 of 6)
    Johnson, Robert Neil, 1978, Nevada Utah Gem Atlas: Cy Johnson and Son, Susanville, California.

    Type_of_Source_Media: paper
    Source_Contribution: site location descriptions

    Klein, 1983 (source 2 of 6)
    Klein, James, 1983, Where to Find Gold and Gems in Nevada: Gem Guides Book Co., Pico Rivera, California.

    Type_of_Source_Media: paper
    Source_Contribution: site location descriptions

    Mitchell, 1991 (source 3 of 6)
    Mitchell, James R., 1991, Gem Trails of Nevada: Gem Guides Book Co., Baldwin Park, California.

    Type_of_Source_Media: paper
    Source_Contribution: site location descriptions

    Murphy,1975 (source 4 of 6)
    Murphy, J.B., 1975, Rockhound's Map of Nevada: Special Publication 1, Nevada Bureau of Mines and Geology, Nevada.

    Type_of_Source_Media: paper map
    Source_Scale_Denominator: 100000
    Source_Contribution: site locations

    MRDS, 1995 (source 5 of 6)
    U.S. Geological Survey, 1995, Minerals Resources Data System (MRDS): U.S. Geological Survey, Reston, VA.

    Type_of_Source_Media: digital database
    Source_Contribution: Cryptocrystalline site locations

    mrds shapefile and mrds_crypto coverage (source 6 of 6)
    Moyer, Lorre A. , 1999, Preliminary digital map of cryptocrystalline occurrences in northern Nevada: mrds (ArcView shapefile) and mrds_crypto (ArcInfo point coverage): U.S. Geological Survey Open-File Report 99-523, U.S. Geological Survey, Spokane, WA.

    Online Links:

    Type_of_Source_Media: digital data
    Source_Contribution:
    The MRDS point theme was used with a polygon theme shapefile derived from Nevada rockhound guides to create a preliminary map of northern Nevada cryptocrystalline occurrences. The original intent was to identify potential sources of raw materials for tools used by indigenous people of northern Nevada. The dataset was created to assist governmental agencies and others in making resource management decisions through the use of geographic information systems (GIS). Uses of the spatial data set include, but are not limited to natural, and cultural resource management, interdisciplinary activities, recreational rockhounding, and gold exploration.

  2. How were the data generated, processed, and modified?

    Date: 1999 (process 1 of 2)
    The original rockhound descriptions were used to locate sites using the ArcView distance measuring tool in an ArcView polygon theme, rkhnd.shp. The Nevada 1:100,000 scale digital raster graphic (DRG) maps were used as a spatial reference.

    Data sources used in this process:

    • Johnson, 1978
    • Klein, 1983
    • Mitchell, 1991
    • Murphy,1975

    Date: 1999 (process 2 of 2)
    A point coverage of northern Nevada cryptocrystalline occurrences extracted from the U.S. Geological Survey's Minerals Resource Data System (MRDS) and converted into an ArcView shapefile.
    Several search strategies were designed to capture records from the MRDS database that represented cryptocrystalline occurrences. The following searches of MRDS fields were successful using the MRDS subsearch editor: NonOre Minerals CONTAINS opal@, chalcedon@, chert, jasper@ ; Ore Minerals CONTAINS opal@, chalcedon@, Vol@; CommodPresSort CONTAINS gem@, sil@; Host Rock Type CONTAINS opal@, chert@, sil@; DepDescComments CONTAINS crypto@; GeologyComments CONTAINS crypto@, vitr@; USGSModelfirst CONTAINS hot spring@. Obsidian searches of MRDS provided no additional records. The MRDS records meeting the search criteria (128) were converted to DBF files, brought into an ARC/INFO point coverage, projected to UTM Zone 11, and converted to an ArcView shapefile.

    Data sources used in this process:

    • MRDS, 1995

    Data sources produced in this process:

    • mrds shapefile and mrds_crypto coverage

  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?

    Data accuracy varies greatly due to data sources, and reliance on descriptive information in rockhound guides (rather than coordinate locations). For some purposes a field check may be advisable. All attributes created were verified by display in the spatial database, but no formal tests were performed.

  2. How accurate are the geographic locations?

    No tests or field checks were performed, and accuracy varies according to description accuracy in the rockhound guides. Polygon size represents the distribution not quantity of the crytocrystalline material. The smooth polygon shape reflects the lack of point to point accuracy resulting from the location descriptions.

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    The area of interest was within the northern Nevada state boundary and bounded in the south by 39 degrees north lattitude. The cryptocrystalline materials considered were chalcedony, chert, jasper, opal, obsidian, and cutting materials.

  5. How consistent are the relationships among the observations, including topology?

    These data are believed to be logically consistent, although no formal tests were performed.

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:
For use at 1:750,000 scale. Spatial data accuracy varies greatly due to data sources, and reliance on descriptive information rather than coordinate locations in rockhound guides. For some purposes a field check may be advisable.

  1. Who distributes the data set? (Distributor 1 of 1)

    U.S. Geological Survey Information Services
    Box 25286
    Denver, Colorado 80225
    USA

    303-202-4200 (voice)
    303-202-4695 (FAX)

  2. What's the catalog number I need to order this data set?

    USGS Open-File Report 99-523

  3. What legal disclaimers am I supposed to read?

    No warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data, software, or related materials.

  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 22-Jun-2000
Last Reviewed: 1999
Metadata author:
U.S. Geological Survey
c/o Lorre A. Moyer
Geologist
USGS C/O Mackay School of Mines MS-176, University of Nevada
Reno, Nevada 89557
USA

775-784-5552 (voice)
775-784-5079 (FAX)
lorre@usgs.gov

Hours_of_Service: 800 - 1600 PT
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

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