Archive of sediment physical properties and grain-size data for sediment samples collected offshore of Assateague Island, Maryland and Virginia

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Frequently anticipated questions:


What does this data set describe?

Title:
Archive of sediment physical properties and grain-size data for sediment samples collected offshore of Assateague Island, Maryland and Virginia
Abstract:
This data release serves as an archive of sediment physical properties and grain-size data for surficial samples collected offshore of Assateague Island, Maryland and Virginia, for comparison with surficial estuarine and subaerial sedimentological samples collected and assessed following Hurricane Sandy (Ellis and others, 2015 (http://doi.org/10.3133/ofr20151219); Smith and others, 2015 (http://doi.org/10.3133/ofr20151169); Bernier and others, 2016 (https://pubs.usgs.gov/ds/0999/)). The sediment samples were collected by scientists from the U.S. Geological Survey (USGS) office in Woods Hole, Massachusetts while aboard the motor vessel (M/V) Scarlett Isabella as part of a larger effort to map the inner continental shelf (Pendleton and others, 2016 (http://doi.org/10.5066/F7MW2F60)). Following field work, the sediment samples were shipped to the USGS Coastal and Marine Science Center in St. Petersburg, Florida, where they were renamed for consistency with a previously existing naming scheme and processed for bulk density, loss on ignition (LOI), and grain-size. The grain-size subsamples were processed on a Coulter LS200 particle-size analyzer for consistency regarding methods and output statistics with related data sets from Chincoteague Bay and Assateague Island. For more information regarding sample collection and site information or the related data sets, refer to USGS data release Pendleton and others, 2016 (http://dx.doi.org/10.5066/F7MW2F60); for more information regarding processing methods refer to USGS Open-File Report 2015–1219 (http://doi.org/10.3133/ofr20151219). Downloadable data are available as Excel spreadsheets (.xlsx), comma-separated values text files (.csv), and formal Federal Geographic Data Committee (FGDC) metadata.
Supplemental_Information:
The unedited output files with statistics for each sample run along with averaged statistics for each sample generated by the USGS Average and Check Standard Deviation macro are available upon request. The averaged results for the subset of statistical parameters that apply to these data are summarized in two spreadsheets, which can be downloaded from http://dx.doi.org/10.5066/F7HX19WB/14CTB-OffshoreG_Compiled_Grain-Size_Summary_Gradistat.zip.
  1. How might this data set be cited?
    Ellis, Alisha M., Wheaton, Cathryn J., and Smith, Christopher G., 20170630, Archive of sediment physical properties and grain-size data for sediment samples collected offshore of Assateague Island, Maryland and Virginia: U.S. Geological Survey Data Release doi:10.5066/F7HX19WB.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -75.436266
    East_Bounding_Coordinate: -75.835042
    North_Bounding_Coordinate: 38.13240
    South_Bounding_Coordinate: 37.700491
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 22-Jul-2014
    Ending_Date: 25-Jul-2014
    Currentness_Reference:
    Ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: Tabular digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
    2. What coordinate system is used to represent geographic features?
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    The detailed attribute descriptions for the statistics summary workbooks are provided in the included data dictionary (http://dx.doi.org/10.5066/F7HX19WB/Grain-Size_Data_Dictionary.pdf). These metadata are not complete without this file.
    Entity_and_Attribute_Detail_Citation:
    Data Dictionary for Grain Size Data Tables, in: Ellis and others, Detailed sediment grain-size statistics for the sediments offshore of Assateague Island, Maryland and Virginia: U.S. Geological Survey Data Release, http://dx.doi.org/10.5066/F7HX19WB.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Alisha M. Ellis
    • Cathryn J. Wheaton
    • Christopher G. Smith
  2. Who also contributed to the data set?
    U.S. Geological Survey, Coastal and Marine Geology Program, St. Petersburg Coastal and Marine Science Center
  3. To whom should users address questions about the data?
    U.S. Geological Survey
    Attn: Alisha M. Ellis
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    aellis@usgs.gov

Why was the data set created?

The file 14CTB-OffshoreG_Compiled_Grain-Size_Summary_Gradistat.zip includes spreadsheets summarizing particle size analysis results for each surface sample collected during the July 2014 sampling trip.

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: 2014 (process 1 of 2)
    19 surface sediment samples were collected offshore of Assateague Island using a VanVeen sediment sampler attached to a SEABOSS (Blackwood et al., 2000). Samples were transported to the USGS St. Petersburg Coastal and Marine Science Center (SPCMSC) for analysis. Prior to particle size analysis, sediment samples which appeared to consist of greater than 5 percent organic material had the organic matter chemically removed from the samples using approximately 8 mL of 30 percent hydrogen peroxide (H2O2) in 50 milliliter beakers overnight. The H2O2 was then evaporated through slow heating on a hot plate, and the sediment was washed and centrifuged twice with deionized water. Samples which appeared to consist of less than 5 percent organic material were dried at 60 degrees C. To prevent shell fragments from damaging the Coulter LS200, particles greater than 1 mm in diameter were separated from all samples prior to analysis with a number 18 (1000 µm) U.S. standard sieve, which meets the American Society for Testing and Materials (ASTM) E11 standard specifications for determining particle size with woven-wire test sieves. The samples were washed through the sieve with filtered municipal water and a few milliliters of sodium hexametaphosphate solution to act as a deflocculant. The sediment slurry was sonicated with a wand sonicator for 30–60 seconds before being introduced into the Coulter LS200 to break down aggregated particles. Two subsamples from each sample were processed through the Coulter LS200 with a minimum of four runs apiece. The Coulter LS200 measures the particle-size distribution of each sample by passing sediment suspended in solution between two narrow panes of glass in front of a laser. The particles scatter light into characteristic refraction patterns that are measured by an array of photodetectors as intensity per unit area and recorded as relative volume for 92 size-classification channels, or bins. The size-classification boundaries for each bin were based on the ATSM E11 standard specification for wire cloth and sieves for testing purposes. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alisha M. Ellis
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    aellis@usgs.gov
    Date: 2014 (process 2 of 2)
    The raw grain-size data were then run through the free software program, GRADISTAT version 8, (Blott and Pye, 2001; kpal.co.uk/gradistat),which calculates the mean, median, sorting, skewness, and kurtosis of each sample geometrically in metric units and logarithmically in phi units (Krumbein, 1934) using the Folk and Ward (1957) method. GRADISTAT also calculates the fraction of sediment from each sample by size category (for example, clay, coarse silt, fine sand) based on Friedman and Saunders (1978), a modified Wentworth (1922) size scale. A macro function in Microsoft Excel, developed by the USGS SPCMSC, was applied to the data to calculate the average and standard deviation for each sample set (8 runs per sample), and highlight runs that varied from the set average by more than ± 1.5 standard deviations. Excessive deviations from the mean are likely the result of equipment error or extraneous organic material in the sample and are not considered representative of the sample. The highlighted runs were removed from the results, and the sample average was recalculated using the remaining runs. The raw, unaltered, individual run statistics and class size distribution as produced by GRADISTAT version 8 (Blott and Pye, 2001), as well as the averaged run statistics and class size distributions, are available upon request. The averaged results for all samples, including the number of runs included and the standard deviation of the averaged results were summarized in an Excel workbook. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alisha M. Ellis
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    aellis@usgs.gov
    Data sources produced in this process:
    • 14CTB-OffshoreG_Compiled_Grain-Size_Summary_Gradistat.zip
  3. What similar or related data should the user be aware of?
    Blott, S.J. and Pye, K., 2001, Gradistat: A grain size distribution and statistics package for the analysis of unconsolidated sediments: Earth Surface Processes and Landforms Volume 26.

    Online Links:

    Other_Citation_Details: Pages 1237-1248
    Ellis, A.M., Marot, M.E., Wheaton, C.J., Bernier, J.C., and Smith, C.G., 2015, A seasonal comparison of surface sediment characteristics in Chincoteague Bay, Maryland and Virginia, USA: U.S. Geological Survey Open-File Report 2015-1219.

    Online Links:

    Smith, C.G., Marot, M.E., Ellis, A.M., Wheaton, C.J., Bernier, J.C., and Adams, C.S., 2015, Sedimentological and radiochemical characteristics of marsh deposits from Assateague Island and the adjacent vicinity, Maryland and Virginia, following Hurricane Sandy: U.S. Geological Survey Open-File Report 2015-1169.

    Online Links:

    Bernier, J.C., Zaremba, N.J., Wheaton, C.J., Ellis, A.M., Marot, M.E., and Smith, C.G., 2016, Sedimentologic characteristics of recent washover deposits from Assateague Island, Maryland: U.S. Geological Survey Data Series ds999.

    Online Links:

    Pendleton, E.A., Ackerman, S.D., Baldwin, W.E., Danforth, W.W., Foster, D.S., Thieler, E.R., and Brothers, L.L., 2016, High-resolution geophysical data collected along the Delmarva Peninsula 2014, U.S. Geological Survey Field Activity 2014-002-FA: U.S. Geological Survey Data Release F7MW2F60.

    Online Links:

    Blackwood, D., Parolski, K., and Valentine, P., 2000, Seabed observation and sampling system: U.S. Geological Survey Fact Sheet FS-142-00.

    Online Links:

    Folk, R.L. and Ward, W.C., 1957, Brazos River bar: A study in the significance of grain size parameters: SEPM Journal of Sedimentary Petrology Volume 27.

    Online Links:

    Other_Citation_Details: Pages 3-26
    Friedman, G.M., and Sanders, J.E., 1978, Principles of Sedimentology.

    Other_Citation_Details: 792 Pages
    Krumbein, W.C., 1934, Size frequency distributions of sediments: SEPM Journal of Sedimentary Petrology Volume 4.

    Online Links:

    Other_Citation_Details: Pages 65-77
    Wentworth, C.K., 1922, A scale of grade and class terms for clastic sediments: Journal of Geology Volume 30.

    Online Links:

    Other_Citation_Details: Pages 377-392

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

  1. How well have the observations been checked?
    The grain size data presented in the run statistics spreadsheets (http://dx.doi.org/10.5066/F7HX19WB/14CTB-OffshoreG_Compiled_Grain-Size_Summary_Gradistat.zip) represent the sample averages for a subset of the statistical parameters calculated by GRADISTAT. The number of runs included in the averaged results are also reported, and the standard deviation of the averaged results are reported for most parameters.
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    This is a complete grain size dataset that includes results for 19 surface sediment samples collected offshore of Assateague Island, Virginia and Maryland.
  5. How consistent are the relationships among the observations, including topology?
    The complete grain size dataset including all GRADISTAT parameters, results of individual sample runs, and standard deviations for all sample averages are available upon request. Sample runs in the output files for which the mean Folk and Ward grain size varied from the set average by more than 1.5 standard deviations are highlighted in yellow and were not included in final averaged results.

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:
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. The U.S. Geological Survey requests that it be acknowledged as the originator of this dataset in any future products or research derived from these data.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Attn: Alisha M. Ellis
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    aellis@usgs.gov
  2. What's the catalog number I need to order this data set? 14CTB-OffshoreG_Compiled_Grain-Size_Summary_Gradistat.zip
  3. What legal disclaimers am I supposed to read?
    Although these data have been processed successfully on a computer system at the U.S. Geological Survey, 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 imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. government.
  4. How can I download or order the data?
  5. What hardware or software do I need in order to use the data set?
    The workbook included in this .zip file was created for use with Microsoft Excel 2016. They may also be viewed with the Microsoft Excel viewer or by downloading a Microsoft Compatibility Pack to view with older versions of Microsoft Excel.

Who wrote the metadata?

Dates:
Last modified: 18-Mar-2019
Metadata author:
U.S. Geological Survey
Attn: Alisha M. Ellis
Geologist
600 4th Street South
St. Petersburg, FL
USA

(727) 502-8000 (voice)
aellis@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/Grain_Size-met.faq.html>
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