Geologic map and database of the Salem East and Turner 7.5 minute quandrangles, Marion County, Oregon: A digital database

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Frequently anticipated questions:

What does this data set describe?

Geologic map and database of the Salem East and Turner 7.5 minute quandrangles, Marion County, Oregon: A digital database
This digital map database, compiled from previously published and unpublished data, and new mapping by the authors, represents the general distribution of bedrock and surficial deposits of the Salem East and Turner 7.5 minute quadrangles. A previously published adjacent geologic map and database by Tolan, Beeson, and Wheeler (1999) contains a text file (geol.txt or, it provides current information on the geologic structure and stratigraphy of the area covered. The database delineates map units that are identified by general age and lithology following the stratigraphic nomenclature of the U.S. Geological Survey. The scale of the source maps limits the spatial resolution (scale) of the database to 1:24,000 or smaller.
The databases in this report were compiled in ARC/INFO, a commercial Geographic Information System (Environmental Systems Research Institute, Redlands, California), with version 3.0 of the menu interface ALACARTE (Fitzgibbon and Wentworth, 1991, Fitzgibbon, 1991, Wentworth and Fitzgibbon, 1991). The files are in either GRID (ARC/ INFO raster data) format or COVERAGE (ARC/INFO vector data) format. Coverages are stored in uncompressed ARC export format (ARC/INFO version 7.x). ARC/INFO export files (files with the .e00 extension) can be converted into ARC/INFO coverages in ARC/INFO (see below) and can be read by some other Geographic Information Systems, such as MapInfo via ArcLink and ESRI's ArcView (version 1.0 for Windows 3.1 to 3.11 is available for free from ESRI's web site: The digital compilation was done in version 7.1.1 of ARC/INFO with version 3.0 of the menu interface ALACARTE (Fitzgibbon and Wentworth, 1991, Fitzgibbon, 1991, Wentworth and Fitzgibbon, 1991). The geologic map information was digitized from stable originals of the geologic maps at 1:24,000 scale. The author manuscripts (pen on mylar and pen on paper) were scanned using a Anatek rasterizing color scanner with a resolution of 600 and 400 dots per inch. The scanned images were vectorized and transformed from scanner coordinates to projection coordinates with digital tics placed by hand at quadrangle corners. The scanned lines were edited interactively by hand using ALACARTE, color boundaries were tagged as appropriate, and scanning artifacts visible at 1:24,000 were removed.
  1. How might this data set be cited?
    Tolan, Terry L., and Beeson, Marvin H., 2000, Geologic map and database of the Salem East and Turner 7.5 minute quandrangles, Marion County, Oregon: A digital database: U.S. Geological Survey Open-File Report 00-351, U.S. Geological Survey, Menlo Park, CA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -123.000020
    East_Bounding_Coordinate: -122.874708
    North_Bounding_Coordinate: 44.999997
    South_Bounding_Coordinate: 44.874995
  3. What does it look like? (GIF)
    "Thumbnail" graphic depiction of Salem quad map, 288x330 pixels, 24-bit color. (GIF)
    "Thumbnail" graphic depiction of Turner quad map, 288x331 pixels, 24-bit color. (PDF)
    A PDF representation of Sheet 1, the Salem East geologic map at a scale of 1:24,000 and list of map units. 4.1 megabytes (PDF)
    A JPEG representation of Sheet 1, the Turner geologic map at a scale of 1:24,000 and list of map units. 4.2 megabytes
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2000
    publication date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital data
  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):
      • Complete chain
      • Entity point
      • GT-polygon composed of chains
      • Point
    2. What coordinate system is used to represent geographic features?
      The map projection used is Transverse Mercator.
      Projection parameters:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -123
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000
      False_Northing: 0.0
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000032
      Ordinates (y-coordinates) are specified to the nearest 0.000032
      Planar coordinates are specified in meters
      The horizontal datum used is D_Clarke_1866.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.400000.
      The flattening of the ellipsoid used is 1/294.978698.
  7. How does the data set describe geographic features?

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Terry L. Tolan
    • Marvin H. Beeson
  2. Who also contributed to the data set?
    T.L. Tolan and M.H. Beeson
  3. To whom should users address questions about the data?
    Chris B DuRoss
    U.S. Geological Survey
    345 Middlefield Road, MS 975
    Menlo Park, CA

    650-566-9772 (voice)

Why was the data set created?

This database and accompanying plot files depict the distribution of geologic materials and structures at a regional (1:24,000) scale. The report is intended to provide geologic information for the regional study of materials properties, earthquake shaking, landslide potential, mineral hazards, seismic velocity, and earthquake faults. In addition, the report contains new information and interpretations about the regional geologic history and framework. However, the regional scale of this report does not provide sufficient detail for site development purposes. In addition, this map does not take the place of fault-rupture hazard zones designated by the Oregon State Geologist (REF?). Similarly, the database cannot be used to identify or delineate landslides in the region.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?

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

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: none
Uses of this digital geologic map should not violate the spatial resolution of the data. Although the digital form of the data removes the constraint imposed by the scale of a paper map, the detail and accuracy inherent in map scale are also present in the digital data. The fact that this database was edited for a scale of 1:24,000 means that higher resolution information is not present in the dataset. Plotting at scales larger than 1:24,000 will not yield greater real detail, although it may reveal fine-scale irregularities below the intended resolution of the database. Similarly, where this database is used in combination with other data of higher resolution, the resolution of the combined output will be limited by the lower resolution of these data.
  1. Who distributes the data set? (Distributor 1 of 1)
    Database Coordinator
    U.S. Geological Survey
    345 Middlefield Rd., M/S 975
    Menlo Park, CA

  2. What's the catalog number I need to order this data set? USGS Open File Report 00-351
  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 publication 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.
  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 10-Jun-2016
Metadata author:
Peter N Schweitzer
USGS Midwest Area
Collection manager, USGS Geoscience Data Clearinghouse,
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)

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