10 cm intervals of percent sand content for 186 sediment cores collected in San Francisco Bay, CA, 1990-2016

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Frequently anticipated questions:

What does this data set describe?

Title:
10 cm intervals of percent sand content for 186 sediment cores collected in San Francisco Bay, CA, 1990-2016
Abstract:
Percentage of sand content provided in 10 cm intervals down the length of 186 sediment cores collected in San Francisco Bay, California in 1990-91, 2000, 2006, and 2016. Sediment data were obtained from a combination of gravity, box, and push cores ranging in length from 14 to 360 cm. Sand content percentages were obtained from a compilation of visual analyses, descriptive and graphical core logs, and grain size measurements. For the purposes of modeling variability in sand content with depth beneath the San Francisco Bay floor, percent sand content values were converted from variable layer thicknesses based upon natural breaks within the core, to regularly spaced 10-cm intervals using a weighted average.
Supplemental_Information:
Additional information about the field activity or activities from which these data were derived is available online at:
https://cmgds.marine.usgs.gov/fan_info.php?fan=J190SF https://cmgds.marine.usgs.gov/fan_info.php?fan=J191SF https://cmgds.marine.usgs.gov/fan_info.php?fan=J200SF https://cmgds.marine.usgs.gov/fan_info.php?fan=2016-671-FA
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 Federal Geographic Data Committee-compliant metadata file is intended to document the dataset in nonproprietary form, as well as in Esri format, this metadata file may include some Esri-specific terminology.
  1. How might this data set be cited?
    Fregoso, Theresa A., Foxgrover, Amy C., and Jaffe, Bruce E., 20250723, 10 cm intervals of percent sand content for 186 sediment cores collected in San Francisco Bay, CA, 1990-2016: data release DOI:10.5066/P9Y7W1ZM, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Fregoso, Theresa A., Foxgrover, Amy C., Kharrazi, Bethany, and Jaffe, Bruce E., 2025, Estimates of percent sand in cores collected in San Francisco Bay, California.: Data Release DOI:10.5066/P9Y7W1ZM, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

    Other_Citation_Details:
    Suggested Citation: Fregoso, T.A., Foxgrover, A.C., Kharrazi, B., and Jaffe, B.E., 2025, Estimates of percent sand in cores collected in San Francisco Bay, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9Y7W1ZM.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -122.507046
    East_Bounding_Coordinate: -121.863877
    North_Bounding_Coordinate: 38.133552
    South_Bounding_Coordinate: 37.448070
  3. What does it look like?
    SFBayCoreLocations.png (PNG)
    Map depicting the location and source of cores included in this study
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 20-Jan-1990
    Ending_Date: 21-Oct-2016
    Currentness_Reference:
    publication date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: comma-delimited text
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (186)
    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 0.00001. Longitudes are given to the nearest 0.00001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is World Geodetic System 1984 (WGS84).
      The ellipsoid used is WGS84.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    SanFranciscoBayPerSand10cmCores
    Table of sand percent values of a core by 10 cm intervals (Source: Producer Defined)
    Core_ID
    The core ID (Source: producer defined) For A/C cores, the core IDs begin with of the last two numbers of the year collected, followed by a dash and sequential numbers assigned on day of collection. For Jaffe cores, cores begin with BC for box cores, or GC or GCC for gravity cores, followed by a dash and sequential numbers assigned on day of collection. Watt cores begin with SPB followed by sequential numbers assigned on day of collection. Yee cores begin with initials representing subembayment (SB – south bay, LSB – lower south bay, SU – Suisun, CB – Central Bay, SPB – San Pablo Bay), followed either by sequential numbers assigned on day of collection or more descriptive place name.
    Bay
    Subembayment where core is located (Source: producer defined)
    ValueDefinition
    SuisunSubembayment
    San PabloSubembayment
    CentralSubembayment
    SouthSubembayment
    Lower SouthSubembayment
    Source
    The principal investigator leading the core collection project. These values correspond to the Survey attribute in SanFranciscoCoreSedimentAnalysis.csv(from this same data release) (Source: producer defined)
    ValueDefinition
    A/CSurvey Identifier for Anima/Clifton, J190SF and J191SF
    JaffeSurvey Identifier for J200SF
    WattSurvey Identifier for 2016-671-FA
    YeeSurvey Identifier for Yee 2011
    year
    Year core collected (Source: producer defined)
    Range of values
    Minimum:1990
    Maximum:2016
    Units:years
    Longitude
    longitude WGS84 (Source: producer defined)
    Range of values
    Minimum:-122.47317
    Maximum:-122.03090
    Units:degree
    Latitude
    latitude WGS84 (Source: producer defined)
    Range of values
    Minimum:37.45950
    Maximum:38.10355
    Units:degree
    XUTM
    X UTM NAD83 zone 10 north. (Source: producer defined)
    Range of values
    Minimum:546303.6
    Maximum:585012.3
    Units:meters
    YUTM
    y UTM NAD83 zone 10 north. (Source: producer defined)
    Range of values
    Minimum:4146268.7
    Maximum:4217483.7
    Units:meters
    Sand
    presence of sand in core (Source: producer defined)
    ValueDefinition
    YYes sand presence
    NNo sand presence
    length
    length of core (Source: producer defined)
    Range of values
    Minimum:14
    Maximum:360
    Units:cm
    Fn0-10
    Sand content of the 0-10 cm interval from top of core (0), down (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.9808
    Units:percentage in decimal form
    Fn10-20
    Sand content of the 10-20 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.9808
    Units:percentage in decimal form
    Fn20-30
    Sand content of the 20-30 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.9808
    Units:percentage in decimal form
    Fn30-40
    Sand content of the 30-40 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.9808
    Units:percentage in decimal form
    Fn40-50
    Sand content of the 40-50 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.9808
    Units:percentage in decimal form
    Fn50-60
    Sand content of the 50-60 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.8448
    Units:percentage in decimal form
    Fn60-70
    Sand content of the 60-70 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:1.0000
    Units:percentage in decimal form
    Fn70-80
    Sand content of the 70-80 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:1.0000
    Units:percentage in decimal form
    Fn80-90
    Sand content of the 80-90 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:1.0000
    Units:percentage in decimal form
    Fn90-100
    Sand content of the 90-100 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.9500
    Units:percentage in decimal form
    Fn100-110
    Sand content of the 100-110 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.9500
    Units:percentage in decimal form
    Fn110-120
    Sand content of the 110-120 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.9850
    Units:percentage in decimal form
    Fn120-130
    Sand content of the 120-130 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.9500
    Units:percentage in decimal form
    Fn130-140
    Sand content of the 130-140 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.7705
    Units:percentage in decimal form
    Fn140-150
    Sand content of the 140-150 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:1.0000
    Units:percentage in decimal form
    Fn150-160
    Sand content of the 150-160 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.6694
    Units:percentage in decimal form
    Fn160-170
    Sand content of the 160-170 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.8568
    Units:percentage in decimal form
    Fn170-180
    Sand content of the 170-180 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.8568
    Units:percentage in decimal form
    Fn180-190
    Sand content of the 180-190 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.8568
    Units:percentage in decimal form
    Fn190-200
    Sand content of the 190-200 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.7000
    Units:percentage in decimal form
    Fn200-210
    Sand content of the 200-210 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.8000
    Units:percentage in decimal form
    Fn210-220
    Sand content of the 210-220 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.7143
    Units:percentage in decimal form
    Fn220-230
    Sand content of the 220-230 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.5258
    Units:percentage in decimal form
    Fn230-240
    Sand content of the 230-240 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.7000
    Units:percentage in decimal form
    Fn240-250
    Sand content of the 240-250 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.7000
    Units:percentage in decimal form
    Fn250-260
    Sand content of the 250-260 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.7000
    Units:percentage in decimal form
    Fn260-270
    Sand content of the 260-270 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.7000
    Units:percentage in decimal form
    Fn270-280
    Sand content of the 270-280 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.7000
    Units:percentage in decimal form
    Fn280-290
    Sand content of the 280-290 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.7900
    Units:percentage in decimal form
    Fn290-300
    Sand content of the 290-300 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.5000
    Units:percentage in decimal form
    Fn300-310
    Sand content of the 300-310 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.5300
    Units:percentage in decimal form
    Fn310-320
    Sand content of the 310-320 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.5000
    Units:percentage in decimal form
    Fn320-330
    Sand content of the 320-330 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.6000
    Units:percentage in decimal form
    Fn330-340
    Sand content of the 330-340 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.6000
    Units:percentage in decimal form
    Fn340-350
    Sand content of the 340-350 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.5000
    Units:percentage in decimal form
    Fn350-360
    Sand content of the 350-360 cm interval from top of core (0), down, -9999 no data value (Source: producer defined)
    Range of values
    Minimum:0.0000
    Maximum:0.5000
    Units:percentage in decimal form
    Entity_and_Attribute_Overview: The first line of the csv file is a header line.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Theresa A. Fregoso
    • Amy C. Foxgrover
    • Bruce E. Jaffe
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Attn: PCMSC Science Data Coordinator
    2885 Mission Street
    Santa Cruz, CA

    831-427-4747 (voice)
    pcmsc_data@usgs.gov

Why was the data set created?

The sediment core data presented here were compiled for use in a project studying the amount of sand either released from or stored within the bed sediments of San Francisco Bay, California from the 1980s to 2010s. Estimates of the change in sand storage in the bed sediments could be used in larger San Francisco Bay sand budget and transports studies as well as to inform management decisions regarding activities such as dredging and sand mining. This study was funded by the California Coastal Conservancy, and the U.S. Geological Survey Coastal and Marine Hazards and Resources Program.

How was the data set created?

  1. From what previous works were the data drawn?
    Cores (source 1 of 1)
    Fregoso, Theresa A., Kharrazi, Bethany, and Jaffe, Bruce E., 2025, Analysis for estimated percent sand in cores taken from San Francisco Bay, California, 1990-2016: U.S. Geological Survey, online.

    Online Links:

    Type_of_Source_Media: online database
    Source_Contribution: Core information used in dataset from this same data release.
  2. How were the data generated, processed, and modified?
    Date: 2023 (process 1 of 1)
    For each core, percent sand data were derived from a combination of visual and graphical core logs and grain-size analyses and entered into an excel spreadsheet. If the top of the cores had gaps between the top of the core liner and the beginning of the actual sediment core, the distance of the gap was subtracted from the raw depth intervals to vertically adjust the zero (0) value to the bed surface. Variations in sand content with depth were interpolated to regularly spaced 10 cm intervals using a weighted average and data from all 186 cores were compiled, along with x, y coordinate locations, collection year, and source information into a single spreadsheet. Data sources used in this process:
    • Cores
  3. What similar or related data should the user be aware of?
    Fregoso, Theresa A., Jaffe, Bruce E., Foxgrover, Amy C., Woodrow, Donald, Kharrazi, Bethany, and Orzech, Kevin, 2025, Contributions of erosion, deposition, and human activities to a change in sand storage in the bed of San Francisco Bay, California.

    Online Links:

    Other_Citation_Details:
    Fregoso, T.A., Jaffe, B.E., Foxgrover, A.C., Woodrow, D.L., Kharrazi, B., and Orzech, K., 2025, Contributions of erosion, deposition, and human activities to a change in sand storage in the bed of San Francisco Bay, California, 1980s to 2010s: U.S. Geological Survey Open-File Report 2025–1022, 30 p., https://doi.org/10.3133/ofr20251022.
    Yee, Donald, Bemis, Bryan, Hammond, Douglas, Heim, Wes, Jaffe, Bruce E., Rattonetti, Anthony, and Bergen, Saskia. van, 2011, Age Estimates and Pollutant Concentrations of Sediment Cores from San Francisco Bay and Wetlands..

    Online Links:

    Other_Citation_Details:
    Yee, D., B. Bemis, D. Hammond, W. Heim, B. Jaffe, A. Rattonetti, S. van Bergen. 2011. Age Estimates and Pollutant Concentrations of Sediment Cores from San Francisco Bay and Wetlands. A Technical Report of the Regional Monitoring Program: SFEI Contribution 652. San Francisco Estuary Institute, Oakland, CA. 45pp + Appendices A, B and C.

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

  1. How well have the observations been checked?
    While every effort was made to be precise in measurements, quality of preservation of individual cores, determined recorded sediment intervals in core logs. Estimating the percent sand in cores from handwritten core logs is, fundamentally, subjective. Users are advised to read the companion open-file report accompanying this data release for additional information.
  2. How accurate are the geographic locations?
    Data are as accurate as source data used. Users are advised to read the metadata record for the sources for horizontal accuracy details. No further accuracy tests were conducted.
  3. How accurate are the heights or depths?
    Data are as accurate as source data used. Users are advised to read the metadata record for the sources for horizontal accuracy details. No further accuracy tests were conducted.
  4. Where are the gaps in the data? What is missing?
    There are additional sediment cores and core logs that were not included in this data release for several possible reasons: (1) the core was outside of this project study area, (2) the core data have been released as part of another study, or 3) the original core could not be located for analysis.
  5. How consistent are the relationships among the observations, including topology?
    Attributes mean the same thing throughout the dataset.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints No access constraints
Use_Constraints USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey. This information is not intended for navigation purposes.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - CMGDS
    2885 Mission Street
    Santa Cruz, CA

    831-427-4747 (voice)
    pcmsc_data@usgs.gov
  2. What's the catalog number I need to order this data set? These data are available in csv format accompanied by CSDGM FGDC-compliant metadata.
  3. What legal disclaimers am I supposed to read?
    Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: Zip file contains the csv table and the associated metadata. in format comma-delimited text (version Microsoft Excel 2302 Build 16130.20766) Size: 0.0729
      Network links: https://doi.org/10.5066/P913V4S1
    • Cost to order the data: None.

  5. What hardware or software do I need in order to use the data set?
    These data can be viewed with any spreadsheet or word processing software capable of opening CSV files.

Who wrote the metadata?

Dates:
Last modified: 23-Jul-2025
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA

831-427-4747 (voice)
pcmsc_data@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/DataReleases/CMGDS_DR_tool/DR_P9Y7W1ZM/SanFranciscoBayPerSand10cmCores_metadata.faq.html>
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