Sediment distribution on a stream-dominated continental margin, Northern California; Implications from heavy-mineral studies

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Frequently-anticipated questions:

What does this data set describe?

Sediment distribution on a stream-dominated continental margin, Northern California; Implications from heavy-mineral studies
Abstract: No formal abstract is given.
"This research was supported by the Pacific OCS Office of the Bureau of Land Management in Los Angeles and we are appreciative of their support." Data concatenated with OFR 80-1080 in 2005 for inclusion into usSEABED (<>)
  1. How should this data set be cited?

    Wong, Florence L. , 1995, Sediment distribution on a stream-dominated continental margin, Northern California; Implications from heavy-mineral studies: Open-file report 95-614, U.S. Geological Survey, Menlo Park, CA.

    Online Links:

    • <>

    Data from USGS cruises S977NC (<>) and S1278NC (<>. Additional data from Humboldt (CA) State University cruise TO, ER, and K, and from several adjacent rivers.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -125.0117
    East_Bounding_Coordinate: -124.0750
    North_Bounding_Coordinate: 41.9333
    South_Bounding_Coordinate: 40.2917

  3. What does it look like?

    OFR_95-614 (JPG)
    Screen grab of GIS-produced sample distribution, with bathymetry and land for reference.

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

    Beginning_Date: 11-Nov-1977
    Ending_Date: 12-Nov-1978
    Currentness_Reference: Publication date

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

    Geospatial_Data_Presentation_Form: Paper

  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):

      • Point (83)

    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 0.0001. Longitudes are given to the nearest 0.0001. Latitude and longitude values are specified in Decimal degrees.

  7. How does the data set describe geographic features?

    SDTS point (Source: Source report)

    Sample number
    Sample number (Source: US Geological Survey)

    Alpha numeric number based on cruise and core information

    Water depth
    Depth of water at sample site (Source: Source report)

    Range of values

    Mineral identification and percentage
    Mineral identification and percentage (Source: Wentworth, 1932)

    Percentages of actinolite, apatite, augite, basaltic hornblende, blue-green amphibole, brown hornblende, colorless clinopyroxene, enstatite, epidote, garnet, glaucophane, green hornblende, heavy minerals , hypersthene, lawsonite, opaque minerals, other minerals, rock fragments, spinel, termolite, tourmaline, unknown minerals, and zircon

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?

    Michael E. Field, Samuel H. Clarke, Jr. and Michael E. White at the USGS for collection of samples and Florence Wong for the analysis of data. For usSEABED, formatting: Jane Reid (USGS); Formatting corrections: Jane Reid (USGS) and Chris Jenkins (University of Colorado)

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

    United States Geological Survey
    USGS Information Services
    Denver, CO 80225

    1-800-ASK-USGS (voice)

Why was the data set created?

"The purpose of this study is to use heavy minerals to distinguish the river sources off northern California, to refine the dispersal pattern previously identified for Klamath sediment, and to determine the contribution of the Eel River to the shelf and slope sediments."

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: Unknown (process 1 of 1)
    " The subsamples were treated with hydrogen peroxide and washed through 250-gm and retained on 63-gm sieves. This size range includes most of the heavy minerals in the sand-size fraction. Heavy minerals were separated in tetrabromoethane diluted to a specific gravity of 2.89 + 0.01. Sample weights taken before and after separation were used to determine an approximate heavy-mineral weight percent (Appendix). Heavy-mineral grains were permanently mounted on glass slides in piccolyte (r.i. = 1.52). Except for a few samples, more than 300 grains were counted on each slide to include at least 200 nonopaque grains. The data were recalculated to 100 percent nonopaque grains (Appendix) and are summarized in Table 2." Textural data from OFR 80-1080 by M.E. Field, S. Clarke, Jr. and M. E. White. Metadata for that report is given separately.

  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?

    No estimate made for the accuracy of the data in the original report. Data digitized by the USGS and partners were visually compared to the source data, and corrected. Where appropriate, data were tested for completeness using MS Excel. Locations checked using GIS.

  2. How accurate are the geographic locations?

    From OFR 80-1080: "Positioning data were obtained at sea using satellite navigation and Loran C systems, and a shipborne electronic ranging system employing shore- based transponders. Radar was used infrequently for positioning where terrain masking or equipment malfunctions were encountered. Data from the satellite and Loran C systems were integrated by means of a Dead Reckoning computer (DRC). Positions derived from the DRC and electronic ranging systems initially were plotted separately and weighted according to their relative accuracy; subsequently these data were corrected and merged to produce maps of position location for geophysical tracklines and sampling stations. Estimated position accuracy ranges from + 50 m where positions were determined principally by electronic ranging (approximately 90 percent of the cruise) to an average of about + 500 m where DRC or radar positions were used exclusively (approximately 10 percent of the cruise). Positions given to 0.0001 decimal degrees."

  3. How accurate are the heights or depths?

    Precision bathymetric and shallow subbottom records were obtained using 12 kHz and 3.5 kHz profiling systems employing hull-mounted transducers and hydrophones. Subsample depths given as nearest centimeter.

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

    No estimate made for original data. For inclusion into usSEABED, all data in the report were included.

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

    Data fall within normal ranges for the given parameters.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

None. Paper copy of report is available through the USGS, and is also available online.
Cite Florence Wong and the U.S. Geological Survey as the originators of the data.

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

    United States Geological Survey
    USGS Information Services
    Denver, CO 80225

    1-800-ASK-USGS (voice)

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

    Open file report 95-614

  3. What legal disclaimers am I supposed to read?

    Although this dataset has been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data. Users of the data should be aware of limitations of the data due to possible imprecision due to navigational inaccuracies and limitations of the statistical data.

  4. How can I download or order the data?

  5. What hardware or software do I need in order to use the data set?

    Plug-in not required, but best viewed with downloadable program DjVu at <>

Who wrote the metadata?

Last modified: 2005
Metadata author:
U.S. Geological Survey
c/o Jane A. Reid
400 Natural Bridges Drive
Santa Cruz, CA 95060

831-427-4727 (voice)

Contact_Instructions: Email preferred
Metadata standard:
CSDGM Version 2 (FGDC-STD-001-1998)

Generated by mp version 2.8.17 on Sat May 20 22:14:12 2006