Recent marine sediments of the central California continental shelf between Point Lobos and Point Sur

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Frequently-anticipated questions:

What does this data set describe?

Title:
Recent marine sediments of the central California continental shelf between Point Lobos and Point Sur
Abstract:
"Seventy sediment samples were collected from the continental shelf between Pt. Lobos and Pt. Sur for textural analysis to determine their statistical properties. Based upon the parameters of mean grain-size, standard deviation, and skewness, three distinct belts of sediments were found. Along the coast the sediments were composed of medium sand-sized, moderately to well sorted particles. Down the center of the shelf a discontinuous band of fine sand occurs in the depths of 35 to 65 fm. The outer band appears to follow the break in the continental shelf and is composed of relatively coarse sediment. Two bathymetric and 3.5 kHz seismic profiling cruises were made through the area. The results of these cruises indicate that the offshore extension of the Palo Colorado fault follows a branch of the Carmel submarine canyon. The primary source of sediments appears to be weathering of coastal rock formations, with sediment distribution due to wave action."
Supplemental_Information:
Data digitized by the USGS for inclusion into usSEABED (<http://walrus.wr.usgs.gov/usseabed>)
  1. How should this data set be cited?

    Herbert Palfrey Colomb, Jr., 1973, Recent marine sediments of the central California continental shelf between Point Lobos and Point Sur: United States Naval Postgraduate School, Monterey, CA.

    Other_Citation_Details: Partial funding through the Office of Naval Research

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -122.0600
    East_Bounding_Coordinate: -121.9100
    North_Bounding_Coordinate: 36.5242
    South_Bounding_Coordinate: 36.2717

  3. What does it look like?

    Colomb_MS_1973 (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?

    Calendar_Date: 1971
    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 (66)

    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 0.00017. Longitudes are given to the nearest 0.00017. Latitude and longitude values are specified in Decimal degrees.

  7. How does the data set describe geographic features?

    Point
    SDTS point (Source: Source report)

    Depth
    Water depth of sample (Source: Colomb, 1973)

    Range of values
    Minimum:36
    Maximum:210
    Units:Meters
    Resolution:1.0

    Gravel
    Gravel (Source: Krumbein and Pettijohn, 1938)

    Range of values
    Minimum:0
    Maximum:74.4
    Units:Percent
    Resolution:0.01

    Sand
    Sand (Source: Krumbein and Pettijohn, 1938)

    Range of values
    Minimum:20.53
    Maximum:99.46
    Units:Percent
    Resolution:0.01

    Silt
    Silt (Source: Krumbein and Pettijohn, 1938)

    Range of values
    Minimum:0.23
    Maximum:15.41
    Units:Percent
    Resolution:0.01

    Mean
    Mean of grainsize distributions (Source: Folk and Ward, 1957)

    Range of values
    Minimum:-1.69
    Maximum:3.53
    Units:Phi
    Resolution:0.01

    Dev.
    Standard deviation of grainsize distribution (sorting) (Source: Folk and Ward, 1957)

    Range of values
    Minimum:-0.67
    Maximum:0.56
    Units:Phi
    Resolution:0.01

    Skew.
    Skewness of grainsize distribution (Source: Folk and Ward, 1957)

    Range of values
    Minimum:0.33
    Maximum:3.69
    Units:Unitless
    Resolution:0.01

    Text
    Descriptive text (Source: Source report)

    Text about the identification of gravel clasts.

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?

    Herbert P. Colomb Jr at the United States Naval Postgraduate School for the collection and analysis of data. For inclusion into usSEABED: Digitization: Jane Reid (USGS); Formatting corrections: Jane Reid (USGS) and Chris Jenkins (University of Colorado)

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

    U.S. Naval Postgraduate School
    1 University Circle
    Monterey, CA 93943

    831.656.2441 (voice)

Why was the data set created?

"The objective of this study was to describe and explain the distribution of the recent sediments along the central California continental shelf between Point Lobos and Point Sur, 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: 1971 (process 1 of 1)
    Grain-size analyses were conducted in accordance with the procedures outline in Krumbein and Pettijohn (1938). Grab samples were split to obtain a representative subsample of about 250 to 300 g. The subsample was then wet-sieved through a 4.0 phi screen to separate the sand and gravel-size fractions from the silt and clay-size fractions...." The dried coarse fraction was sieved at 0.5 phi intervals in a Ro-tap for 10 minutes, and weighed to the nearest 0.1 mg. Fine fraction (< 4.0 phi) were pipetted at 0.5 interval, except those samples which contained less than 5% of the total sample weight were dried and weighed directly. Statistics were computed using a program written by W. R. Anikouchine (Dinger, 1970), including Trask, Inman, and Folk and Ward values as modified by Carter, 1971.

    Person who carried out this activity:

    U.S. Naval Postgraduate School
    1 University Circle
    Monterey, CA 93943

    831.656.2441 (voice)

    Data sources used in this process:
    • Krumbein and Pettijohn, 1938
    • Dinger, 1970

    Data sources produced in this process:

    • Colomb_MS_1973

  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 technique not noted in report. Locations given to nearest hundredth of a decimal minute.

  3. How accurate are the heights or depths?

    Water depths measured by fathometer; water depths given to nearest fathom. No accuracy estimations noted in report.

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

    Digitized data include table 2 and some information in the text.

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

    Data fall within normal ranges for sediment statistics.

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 other libraries
Use_Constraints:
Cite Herbert Palfrey Colomb, Jr. and the U.S. Naval Postgraduate School as the originators of the data.

  1. Who distributes the data set? (Distributor 1 of 2)

    U.S. Naval Postgraduate School
    1 University Circle
    Monterey, CA 93943

    831.656.2441 (voice)

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

    H.P. Colomb, Jr. Masters thesis, 1971

  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?

  1. Who distributes the data set? (Distributor 2 of 2)

    U.S. Geological Survey
    345 Middlefield Road
    Menlo Park, CA 94025

    650.329.5026 (voice)
    men_lib@usgs.gov

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

    536 (276) C714r

  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 the limitations of the data due to possible imprecision due to navigational inaccuracies, statistical limitations, and digitizing errors.

  4. How can I download or order the data?

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

    None

Who wrote the metadata?

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

831-427-4727 (voice)
jareid@usgs.gov

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

Generated by mp version 2.8.17 on Tue May 16 20:36:13 2006