Recent coastal sediments Double Point to Point San Pedro, California

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Frequently-anticipated questions:

What does this data set describe?

Recent coastal sediments Double Point to Point San Pedro, California
"This study seeks to examine patterns of long term sediment movement along a portion of the California coast centering around the mouth of San Francisco Bay. Naturally-occurring heavy minerals were used to trace the influence of the several sources of sediments. Surface samples were collected from beaches and from the adjacent portion of the shelf under less than 130 feet of water. The samples obtained were analyzed mechanically and petrographically. Six petrographic provinces were differentiated on the basis of physical and mineralogical properties. It was found that sands south and west of the Golden Gate in less than 60 to 100 feet of water reflect the mineralogy of San Francisco Bay sediment, and samples from the mollusk-rich Bolinas Bay and adjacent areas to the north and west contained large amounts of aragonite. Sediments in 60 to 100 feet of water west of the Golden Gate are unusually high in hornblende and sediments in more than 100 feet of water are somewhat higher in minerals of the Franciscan Formation than sediments closer to the coast. It is concluded from this information that the San Francisco Bay Bar and adjacent sediments south and west of the Golden Gate bridge have been derived principally from San Francisco Bay, and that sediments in the Bolinas Bay area are derived in large part from the decomposition of shells of modern marine organisms. The areas in 60 to 100 feet of water and greater than 100 feet of water do not appear to have any modern sources of sediment and are interpreted as relicts of features developed during lower sands of sea level. Similarities between sediments in more than 100 feet of water in this area and sediments in the same environment to the north of the area studies suggest a less complicate distribution of sediments and perhaps extensive longshore transport of sediments during this lower stand of sea level. The distribution of recent sediments near the coast in the area studies indicates that longshore transport is now only of limited, local importance."
This work was supported by Contract DA-49-055-CIV-ENG-63-4 with the Coastal Engineering Research Center, Corps of Engineers, U.S. Army. Samples 1683-1745 from Trask's 1954 study (Collected May 1952 to October 1954) Data digitized by the USGS for inclusion into usSEABED (<>)
  1. How should this data set be cited?

    Moore, D.B., 1965, Recent coastal sediments Double Point to Point San Pedro, California: Hydraulic Engineering Laboratory Technical Report HEL-2-14, University of California, Berkeley, CA.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -122.7977
    East_Bounding_Coordinate: -122.4654
    North_Bounding_Coordinate: 37.9456
    South_Bounding_Coordinate: 37.6664

  3. What does it look like?

    HEL2-14 (.jpg)
    Sample distribution with bathymetry and coastline for reference

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

    Calendar_Date: 1964
    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 (181)

    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 .0001. Longitudes are given to the nearest .0001. Latitude and longitude values are specified in Decimal degrees.

  7. How does the data set describe geographic features?

    SDTS point (Source: Source report)

    Water depth (Source: Source report)

    Range of values

    Median grainsize (Source: Source report)

    Range of values

    Sorting coefficient
    Sorting of grainsize (Source: Trask 1932)

    Range of values

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?

    D.B. Moore at the University of California Berkeley for the collection and analysis of data. For inclusion into usSEABED: Digitization: Carolynn Box and Jennifer Mendonca (USGS); Location digitization by Nadine Golden (USGS), Formatting corrections: Jane Reid (USGS) and Chris Jenkins (University of Colorado)

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

    University of California
    Department of Civil and Environmental Engineering
    Berkeley, CA 94720-1710

    510-642-3261 (voice)

Why was the data set created?

"In the past decade, much interest has been generated in the study of the long term movement of Recent sediments. The present study continues this work, concentrating on the coastal shelf sediments west of Marin and San Francisco Counties, California."

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)
    Samples were washed to remove clay, salt, and organic matter, and sieved.

    Person who carried out this activity:

    University of California
    Department of Civil and Environmental Engineering
    Berkeley, CA 94720-1710

    510-642-3261 (voice)

    Data sources produced in this process:
    • HEL-2-14

  3. What similar or related data should the user be aware of?

    Trask, P.D., 1954, San Francisco Bay sediment study: University of California Institute of Engineering Research 57, issues 1 and 2, University of California, Berkeley, CA.

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?

    Navigation by radio compass and ship's compass. Locations were digitized from scanned figure using ArcMap 8.3a.

  3. How accurate are the heights or depths?

    Depth determination by unspecified fathometer. Water depths recorded in feet.

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

    Data from Appendix: statistical data were digitized by hand (typed in), visually compared to source and corrected as needed.. Heavy mineral percents, carbonate percents, and mineral percents not included in usSEABED.

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

    Data fall within normal ranges for statistical values.

How can someone get a copy of the data set?

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

Access_Constraints: Available at the USGS library and others
Cite D.B. Moore and the University of California, Berkeley as the source of the information

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

    University of California
    Department of Civil and Environmental Engineering
    Berkeley, CA 94720-1710

    510-642-3261 (voice)

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

    HEL Report 2-14

  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?


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 Tue May 16 21:16:50 2006