Textural description of surface sediment samples collected in March/April 2014 and October 2014 from Chincoteague Bay, Virginia and Maryland (U.S. Geological Survey Field Activity Numbers 14CTB01, and 14CTB22).

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Frequently anticipated questions:

What does this data set describe?

Title:
Textural description of surface sediment samples collected in March/April 2014 and October 2014 from Chincoteague Bay, Virginia and Maryland (U.S. Geological Survey Field Activity Numbers 14CTB01, and 14CTB22).
Abstract:
Scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center conducted a seasonal collection of surficial sediments from Chincoteague Bay and Tom's Cove, located between Assateague Island and the Delmarva Peninsula in March/April 2014 (2014-301-FA) and October 2014 (2014-322-FA). The sampling efforts were part of a larger U.S. Geological Survey study to assess the effects of storm events on sediment distribution. The objective of this study was to characterize the sediments of Chincoteague Bay in order to create baseline conditions to incorporate with hydrodynamic and sediment transport models in order to evaluate pre- and post-storm (Hurricane Sandy) change. This report serves as an archive for sedimentological data derived from the surface sediment. Data are available for a seasonal comparison between March/April 2014 and October 2014. Downloadable data are available as Excel spreadsheets (sediment samples) and as JPEG files (maps). Additional files include: detailed results of sediment grain size analyses, and formal Federal Geographic Data Committee metadata (data downloads).
Supplemental_Information:
The individual run statistics and class size distribution as well as the averaged run statistics and class size distributions are included in this report's data downloads at http://pubs.usgs.gov/of/2015/1219/2015-1219_data.html. Each data file includes averaged statistics for each sample and the sand-silt-clay ternary diagram generated by GRADISTAT (Blott and Pye, 2001; kpal.co.uk/gradistat). 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 can be downloaded from http://pubs.usgs.gov/of/2015/1219/2015-1219_data.html/14CTB_Spring-and-Fall_Grain-Size-Run-Statistics.xlsx.zip. GRADISTAT calculates statistics for several parameters that do not apply to our dataset or future analyses and therefore are not included in the summarized data files. For example, GRADISTAT also calculates the arithmetic mean grain size of each sample; however, an arithmetic grain-size scale is generally not used in sedimentology because the standard grain-size classifications (Wentworth, 1922) are not based on a normal (Gaussian) distribution, which tends to overemphasize coarse sediment, whereas geometric and their derivative log-normal scales place equal emphasis on the small size differences between fine particles (for example, clay and silt) and the larger size differences between coarse particles (for example, pebbles and cobbles). Other parameters, such as percent gravel, do not apply to this dataset because particles coarser than 1 mm were removed from the samples prior to processing. The averaged results for the subset of statistical parameters that apply to these data are summarized in three spreadsheets, which can be downloaded from http://pubs.usgs.gov/of/2015/1219/images/CTB-Tables/14CTB_Spring-and-Fall_Compiled-Grain-Size-Data.zip.
  1. How might this data set be cited?
    Ellis, Alisha M., Marot, Marci E., Wheaton, Cathryn J., Bernier, Julie C., and Smith, Christopher G., 20151205, Textural description of surface sediment samples collected in March/April 2014 and October 2014 from Chincoteague Bay, Virginia and Maryland (U.S. Geological Survey Field Activity Numbers 14CTB01, and 14CTB22).:.

    Online Links:

    This is part of the following larger work.

    Ellis, Alisha M., Marot, Marci E., Wheaton, Cathryn J., Bernier, Julie C., and Smith, Christopher G., 20151205, A seasonal comparison of surface sediment characteristics in Chincoteague Bay, Maryland and Virginia, USA: U.S. Geological Survey Open-File Report 2015-1219, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -75.46667
    East_Bounding_Coordinate: -75.11111
    North_Bounding_Coordinate: 38.26667
    South_Bounding_Coordinate: 37.82222
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 26-Mar-2014
    Ending_Date: 30-Oct-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://pubs.usgs.gov/of/2015/1219/surface-sediment-characteristics/data/CTB-Tables/Supplemental/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, A Seasonal Comparison of Surface Sediment Characteristics in Chincoteague Bay, Maryland and Virginia, USA: U.S. Geological Survey Open-File Report 2015-1219, https://doi.org/10.3133/ofr20151219.

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
    • Marci E. Marot
    • Cathryn J. Wheaton
    • Julie C. Bernier
    • 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) 502-8056 (voice)
    aellis@usgs.gov

Why was the data set created?

The 14CTB_Spring and Fall_Compiled Grain-Size Data.zip file includes Excel spreadsheets summarizing particle size analysis results from Chincoteague Bay, Maryland and Virginia, collected in Spring March 26 – April 4, 2014 (14CTB01) and fall October 21 – 30, 2014 (14CTB02) by the U.S. Geological Survey (USGS), St. Petersburg Coastal and Marine Science Center.

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 4)
    99 surface sediment samples were collected with a Ponar grab from Chincoteague Bay and Tom’s Cove in March/April and October 2014 (USGS Field Activity Numbers 14CTB01, and 14CTB02). Samples were transported to the USGS St. Petersburg, FL Coastal and Marine Science Center (SPCMSC) for analysis.Prior to particle size analysis, organic material was chemically removed from the samples using approximately 8 mL of 30 percent hydrogen peroxide (H2O2) overnight. The H2O2 was then evaporated through slow heating on a hot plate, and the sediment was washed and centrifuged twice with deionized water. Grain-size analyses on the surface samples were performed using a Coulter LS200 (https://www.beckmancoulter.com) particle size analyzer, which uses laser diffraction to measure the size distribution of sediments ranging in size from clay (0.4 microns [µm]) to very coarse-grained sand (2 millimeters [mm]). A total of 99 surface samples were analyzed. 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 St. Petersburg, FL 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 three 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. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alisha M. Ellis
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8056 (voice)
    aellis@usgs.gov
    Date: 2014 (process 2 of 4)
    The raw grain-size data were then run through the free software program GRADISTAT (Blott and Pye, 2001; http://www.kpal.co.uk/gradistat.html), which calculates the mean, 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 a modified Wentworth (1922) size scale. Entire list of references may be found at http://pubs.usgs.gov/of/2015/1219/ofr2015-1219_references.html. 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 (6 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. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alisha M. Ellis
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8056 (voice)
    aellis@usgs.gov
    Data sources produced in this process:
    • 14CTB_Spring and Fall_Grain-Size Run Statistics.zip
    Date: 2014 (process 3 of 4)
    The averaged results for all samples, including the number of runs included and the standard deviation of the averaged results were summarized in a series of Excel workbooks for each sampling trip. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alisha M. Ellis
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8056 (voice)
    aellis@usgs.gov
    Data sources produced in this process:
    • 14CTB_Spring and Fall_ Compiled Grain-Size Data.xlsx.zip
    Date: 13-Oct-2020 (process 4 of 4)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  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

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://pubs.usgs.gov/of/2015/1219/images/CTB-Tables/14CTB_Spring-and-Fall_Compiled-Grain-Size-Data.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 98 surface sediment samples collected in Chincoteague Bay and Tom’s Cove in March/April, and October 2014 (U.S. Geological Survey Field Activity Numbers 14CTB01, 14CTB22).
  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 included in the unedited output files (http://pubs.usgs.gov/of/2015/1219/images/CTB-Tables/14CTB_Spring-and-Fall_Grain-Size_Run_Statistics.xlsx.zip). 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:
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) 502-8056 (voice)
    aellis@usgs.gov
  2. What's the catalog number I need to order this data set? Downloadable data
  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?
    These workbooks included in this .zip file were created for use with Microsoft Excel 2010. 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: 13-Oct-2020
Metadata author:
U.S. Geological Survey
Attn: Alisha M. Ellis
Geologist
600 4th Street South
St. Petersburg, FL
USA

(727) 502-8056 (voice)
aellis@usgs.gov
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/OFR20151219_Grain_Size-met.faq.html>
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