Lead, Radium, Cesium, and Thorium isotope activity in sediment samples from Los Padres reservoir, Carmel River watershed, California

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Frequently anticipated questions:

What does this data set describe?

Title:
Lead, Radium, Cesium, and Thorium isotope activity in sediment samples from Los Padres reservoir, Carmel River watershed, California
Abstract:
Sediment samples were collected from Los Padres reservoir in the Carmel River watershed, central California coast, between July 11 and 17, 2017, using a CME-45 barge-mounted drill rig, to characterize sedimentary properties in the reservoir deposits following the Soberanes Fire of 2016 and high river flows in winter 2017. Borehole samples were recovered using direct push coring with an Osterberg piston sampler operated by Taber Drilling Company of Sacramento, California, and overseen by AECOM, Inc. Sediment was recovered using a split-barrel sampler and a rotary drill bit was added to the sampler where needed to penetrate coarse sediment. Samples from three boreholes are described in this data release: two sampled at multiple sediment depths (B2 and B7) and a third (B4) from which only the topmost sample is included. Each borehole was drilled to the depth of apparent pre-dam alluvium or bedrock. Alternate sections were described and sampled; every second section was discarded without examination. Geochemical data are reported for sediment cores. Data include short-lived cosmogenic and natural radionuclide activities for Lead-210; Radium-226, Cesium-137, Thorium-234, and excess Lead-210. The USGS gratefully acknowledges collaboration with B. Kozlowicz of AECOM, Inc., in the collection of these data. Purpose: Laboratory measurements of natural lead, radium, cesium, and thorium isotope concentrations in Los Padres reservoir, Carmel River watershed, California, to characterize post-fire sedimentation history.
Supplemental_Information:
This data release is associated with the following data release including grain size and charcoal abundance in Los Padres reservoir sediment samples: https://doi.org/10.5066/P9C7NKM4. Additional information about the field activities from which these data were derived is available online at:
https://cmgds.marine.usgs.gov/fan_info.php?fan=2017-635-FA
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  1. How might this data set be cited?
    Lorenson, Thomas D., and East, Amy E., 20240103, Lead, Radium, Cesium, and Thorium isotope activity in sediment samples from Los Padres reservoir, Carmel River watershed, California: data release DOI:10.5066/P99M6Y8O, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    Other_Citation_Details:
    Suggested Citation: Lorenson, T.D. and East, A.E., 2024, Lead, Radium, Cesium, and Thorium isotope activity in sediment samples from Los Padres reservoir, Carmel River watershed, California, U.S. Geological Survey data release, https://doi.org/10.5066/P99M6Y8O.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -121.666476
    East_Bounding_Coordinate: -121.664314
    North_Bounding_Coordinate: 36.383113
    South_Bounding_Coordinate: 36.380511
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 13-Jul-2017
    Currentness_Reference:
    ground condition at time data were collected
  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 (20)
    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 North American Datum 1983.
      The ellipsoid used is GRS 1980.
      The semi-major axis of the ellipsoid used is 6378137.0000.
      The flattening of the ellipsoid used is 1/298.2572.
  7. How does the data set describe geographic features?
    Attribute table
    Table of data (Source: producer defined)
    Sample_ID
    Sample ID refers to borehole number and depth in borehole (Source: producer defined) unique identifier for each sample
    Date_Collected
    Date of sample collection (Source: producer defined)
    Range of values
    Minimum:07/13/2017
    Maximum:07/16/2017
    Units:mm/dd/yyyy
    Longitude_NAD83
    Longitude of collection (Source: producer defined)
    Range of values
    Minimum:-121.66648
    Maximum:-121.66431
    Units:meters
    Latitude_NAD83
    latitude of sample (Source: producer defined)
    Range of values
    Minimum:36.38051
    Maximum:36.38311
    Units:meters
    Midpoint_depth_cm
    midpoint depth of sample cm (Source: producer defined)
    Range of values
    Minimum:3
    Maximum:1654
    Units:centimeters
    210Pb_total_activity_dpm/g
    Activity of supported, or excess, Lead-210; -9999=not determined (Source: Producer defined)
    Range of values
    Minimum:1.51
    Maximum:9.61
    Units:disintegrations per minute per gram (dpm per g)
    Resolution:0.01
    210Pb_total_uncertainty_dpm/g
    Measurement uncertainty of excess Lead-210 activity estimated from: detector efficiency, background correction, and one standard deviation of the counting error; -9999=not determined (Source: Producer defined)
    Range of values
    Minimum:0.33
    Maximum:1.83
    Units:disintegrations per minute per gram (dpm per g)
    Resolution:0.01
    226Ra_activity_dpm/g
    Activity of supported, or excess, Radium-226; -9999=not determined (Source: Producer defined)
    Range of values
    Minimum:1.64
    Maximum:3.88
    Units:disintegrations per minute per gram (dpm per g)
    Resolution:0.01
    226Ra_uncertainty_dpm/g
    Measurement uncertainty of excess Radium-226 activity estimated from: detector efficiency, background correction, and one standard deviation of the counting error; -9999=not determined (Source: Producer defined)
    Range of values
    Minimum:0.08
    Maximum:0.31
    Units:disintegrations per minute per gram (dpm per g)
    Resolution:0.01
    210Pb_excess_activity_dpm/g
    Activity of supported, or excess, Lead-210; -9999=not determined (Source: Producer defined)
    Range of values
    Minimum:-0.21
    Maximum:6.14
    Units:disintegrations per minute per gram (dpm per g)
    Resolution:0.01
    210Pb_excess_uncertainty_dpm/g
    Measurement uncertainty of excess Lead-210 activity estimated from: detector efficiency, background correction, and one standard deviation of the counting error; -9999=not determined (Source: Producer defined)
    Range of values
    Minimum:0.34
    Maximum:1.86
    Units:disintegrations per minute per gram (dpm per g)
    Resolution:0.01
    137Cs_activity_dpm/g
    Activity of Cesium-137; -9999=not determined (Source: Producer defined)
    Range of values
    Minimum:0.00
    Maximum:2.51
    Units:disintegrations per minute per gram (dpm per g)
    Resolution:0.01
    137Cs_uncertainty_dpm/g
    Measurement uncertainty of Cesium-137 activity estimated from: detector efficiency, background correction, and one standard deviation of the counting error; -9999=not determined (Source: Producer defined)
    Range of values
    Minimum:0.00
    Maximum:1.68
    Units:disintegrations per minute per gram (dpm per g)
    Resolution:0.01
    Th234_activity_dpm/g
    Activity of Thorium-234; -9999=not determined (Source: Producer defined)
    Range of values
    Minimum:1.31
    Maximum:5.71
    Units:disintegrations per minute per gram (dpm per g)
    Resolution:0.01
    234Th_uncertainty_dpm/g
    Measurement uncertainty of Thorium-234 activity estimated from: detector efficiency, background correction, and one standard deviation of the counting error; -9999 =not determined (Source: Producer defined)
    Range of values
    Minimum:0.27
    Maximum:1.33
    Units:disintegrations per minute per gram (dpm per g)
    Resolution:0.01
    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)
    • Thomas D. Lorenson
    • Amy E. East
  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?

Laboratory measurements of isotopic activity in borehole sediment from Los Padres reservoir, Carmel River watershed, California, to characterize post-fire sedimentation history.

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: 25-Oct-2017 (process 1 of 2)
    SEDIMENT COLLECTION. Surface sediment was collected using a benthic grab sampler deployed from a boat. Long cores were collected using a vibracore device deployed from the A-frame of the boat.
    Date: 12-Feb-2020 (process 2 of 2)
    RADIONUCLIDE ACTIVITIES. Prior to quantification of short-lived radionuclide activities, bulk sediment was oven-dried at 60 degrees Celsius, ground by hand in a mortar and pestle and packed into 10 milliliter graduated polystyrene vials. Vials were capped and sealed to prevent gas exchange, then left to equilibrate for at least 21 days. For surface sediment and Cores 3, 5, 6, and 9, samples and reference materials with the same geometry were counted for 24 hours in a high purity, low background germanium (HPGe) well detector at the USGS PCMSC Radiochemistry Lab. Cesium-137 activities were counted at 661 kiloelectron volts (keV), Lead-210 at 46.5 keV, and Radium-226 as the average of indirect peaks at 351.87 keV (Lead-214) and 609.31 keV (Bismuth-214). Unsupported, or excess, Lead-210 was calculated by subtracting supported Lead-210 (assumed to equal average Radium-226 activity) from total Lead-210.
  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?
    For radionuclides, sample activities were calculated by comparison to reference standards with the same geometry and counting time; reported uncertainties include 1 standard deviation counting errors, detector efficiency, and background corrections. Counting efficiency for Cesium-137 was determined by comparison to the International Atomic Energy Agency (IAEA) Standard Reference Material 300. Counting efficiency for Lead-210, Thorium-234, Radium-228, and Radium-226 was determined using IAEA standards RGU-1 and RGTh-1.
  2. How accurate are the geographic locations?
    A Garmin handheld GPS reported a horizontal accuracy of plus or minus 3 meters.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
  5. How consistent are the relationships among the observations, including topology?
    No formal logical consistency tests were conducted.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints None
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 as the originator(s) of the dataset and in products derived from these data.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - ScienceBase
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? These data are available in csv format (Los_Padres_Reservior_Gamma.csv) and includes 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?
  5. What hardware or software do I need in order to use the data set?
    These data can be viewed with any text reader.

Who wrote the metadata?

Dates:
Last modified: 03-Jan-2024
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/ScienceBase/DR_P99M6Y8O/Los_Padres_Reservior_Gamma_metadata.faq.html>
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