Holocene stratigraphy and sedimentation on the northern California continental shelf

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Frequently-anticipated questions:

What does this data set describe?

Holocene stratigraphy and sedimentation on the northern California continental shelf
"The northern California continental shelf can be subdivided into three shelf sections based on sediment characteristics: the Klamath River shelf, from Point St. George to Patricks Point; the Eel River shelf, from Patricks Point to Eel Canyon; and the shelf south of Eel Canyon. Three sediment types predominate on the shelf. The nearshore zone, to a depth of 55 to 65 meters, is covered by fine to very fine sands that are transported by waves. The mid-shelf on the Klamath River shelf is covered by clayey silts or silty clays that accumulate from the Klamath River suspended load. The outer shelf is covered by palimpsest silty sand. On the Eel River shelf, the mid- and outer- shelf is covered by clayey silts or silty clays that accumulate from the Eel River suspended load. On the shelf south of Eel Canyon, muds occur ponded between outcrops of underlying rocks. The clayey silts or silty clays began to accumulate during the Holocene transgression, approximately 10,000 to 12,000 BP. The base of this mud facies is time transgressive; the outer shelf portions began to accumulate prior to the mid-shelf portions. Below the mud facies, late-Quaternary units lie above an unconformity, separating the late-Quaternary units from pre-Quaternary units that make up the shelf platform. These late-Quaternary units crop out on the outer Klamath River shelf where they consist of palimpsest silty sands. The boundary between the Holocene mud facies and the nearshore sand facies is characterized by alternating layers of mud and silty sands. The alternations were produced by a migrating facies boundary due to changes in incoming waves. The facies boundary migrated between at least 46 and 71 meters waters depth during the Holocene. Flood-produced strata are preserved in the Holocene mud facies in the vicinity of the Eel River mouth. These flood-produced strata are composed of brown very fine sands and coarse silts, and contain layers of wood fragments. These flood-produced deposits are restricted to the shelf directly offshore of the Eel River mouth and slightly northward. These deposits were created during the December, 1964, flooding of the Eel River."
Supplemental_Information: Data digitized for inclusion into usSEABED.
  1. How should this data set be cited?

    Borgeld, Jeffry Calvert , 1985, Holocene stratigraphy and sedimentation on the northern California continental shelf: University of Washington, Seattle, WA.

    Textural class (%gravel, sand, silt, clay) data via personal communication from J. Borgeld to M. Zimmermann, 1996

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -124.6100
    East_Bounding_Coordinate: -124.0883
    North_Bounding_Coordinate: 41.7683
    South_Bounding_Coordinate: 40.4333

  3. What does it look like?

    Borgeld_PhD_85 (.jpg)
    Sample distribution with coastline and bathymetry for reference.

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

    Beginning_Date: 1972
    Ending_Date: 1979
    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):

      • Entity point (107)

    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: University of Washington)

    Alpha numeric code based on cruise identification and sample number.

    Cruise number
    Cruise identification (Source: Source report)

    TT141R/V Thomas G. Thompson, August 1979
    TOR/V Catalyst, January 1973 to January 1977
    KR/V Catalyst, March 1972 to October 1973
    ERR/V Catalyst, June 1973
    HSUR/V Catalyst, October 1976

    Sampler type (Source: Source report)

    SMSmith-MacIntyre grab sampler
    SHShipek grab sampler
    SDSediment dredge
    GCGravity core

    Water depth
    Water depth (Source: Source report)

    Range of values

    Mode of grainsize distribution (Source: Source report)

    Range of values

    Median grainsize (Source: Source report)

    Range of values

    Mean grainsize (Source: Inman, 1952)

    Range of values

    Standard deviation of grainsize (Source: Inman, 1952)

    Range of values

    Skewness of grainsize (Source: Inman, 1952)

    Range of values

    Kurtosis of grainsize distribution (Source: Inman, 1952)

    Range of values

    Light minerals
    Minerals with density < 2.96 g/cm3 (Source: Source report)

    Range of values

    Light heavy minerals
    Minerals with density > 2.96 g/cm3 and < 3.32 g/cm3 (Source: Source report)

    Range of values

    Heavy heavy minerals
    Minerals with density > 3.32 g/cm3 (Source: Source report)

    Range of values

    Amount of gravel in sample (Source: Wentworth 1938)

    Range of values

    Amount of sand in sample (Source: Wentworth 1938)

    Range of values

    Amount of silt in sample (Source: Wentworth 1938)

    Range of values

    Amount of clay in sample (Source: Wentworth, 1938)

    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?

    Jeffry Calvert Borgeld at the University of Washington for the collection and analysis of data. For inclusion into usSEABED: digitization: Halimeda Kilbourne (USGS) and Mark Zimmermann (NOAA) Formatting corrections: Jane Reid (USGS) and Chris Jenkins (University of Colorado).

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

    Jeff Borgeld
    Now at Humboldt State University
    Department of Oceanography
    Arcata, CA 95521-8299

    (707) 826-3328 (voice)
    (707) 826-4145 (FAX)

Why was the data set created?

"This treatise represents a contribution to the understanding and characterization of shelf deposits and shelf processes. In particular, the evaluation of flood related stratigraphy on a modern shelf which is presently accumulating sediment."

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)
    Bottom sediment samples were treated with a 30 percent hydrogen peroxide, to oxidize organic matter, and then analyzed using standard sieve (Whitby, 1958; American Society for Testing Materials, 1963); W.S. Tyler Col., 1967) and pipette (Rolfe et al., 1960; Galehouse, 1971) techniques. The pipette analyses were carried out using 1.0 gram per liter sodium hexametaphosphate as a dispersing agents. The sand sizes were dry sieved to 1/4 phi intervals, the silt sizes were pipetted to 1/2 phi intervals, and the clay sizes were pipetted to full phi intervals. Material smaller than 11 phi was collectively grouped and termed 12 phi. Density separations of the sand-sized fractions of samples collected from the shelf during August 1979 and from northern California rivers during September 1979 were performed using standard centrifuge techniques (Rittenhouse and Bertholf, Jr., 1942; Browning, 1961; Carver, 1971). Three density splits, the light minerals (densities less than 2.96 g/cm3), the light heavy minerals (densities between 2.96 and 3.32 g/cm3) and heavy heavy minerals (densities greater than 3.32 g/cm3) were separated using tetrabromoethane (density 2.96 g/cm3) and diiodomethane (density, 3.32 g/cm3). From Jeff Borgeld's email to Mark Zimmermann, 6/17/96: "The samples were sieved to 1/4 phi in the sands and pipetted for the silts and clays. I have individual sample sheets to that level, but no complete summary other than what is included [here]."

    Person who carried out this activity:

    Jeff Borgeld
    Now at Humboldt State University
    Department of Oceanography
    Arcata, CA 95521-8299

    (707) 826-3328 (voice)
    (707) 826-4145 (FAX)

    Data sources used in this process:
    • American Society for Testing Materials, 1963
    • Browning, 1961
    • Carver, 1971
    • Galehouse, 1971
    • Rolfe et al., 1960
    • Rittenhouse and Bertholf, Jr., 1942
    • W.S. Tyler Col.,1967
    • Whitby,1958

    Data sources produced in this process:

    • Borgeld_PhD_1985

  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?

    Navigation method unknown; no assessment made for location accuracy.

  3. How accurate are the heights or depths?

    Depth determination method unknown; no assessment made for accuracy.

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

    All data were digitized, except river samples.

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

    Tests were performed on the textural class values to ensure completeness.

How can someone get a copy of the data set?

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

None. Thesis is available at the USGS Library and other libraries.
Cite Jeff Borgeld and the University of Washington as originators of the data.

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

    University of Washington
    P.O. Box 357940
    Seattle, WA 98195

    206-543-5060 (voice)

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


  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 20:19:42 2006