Maryland Geological Survey: Offshore Sand Resources in Northern Maryland Shoal Fields (Conkwright, et al, 2000)

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Frequently-anticipated questions:

What does this data set describe?

    Maryland Geological Survey: Offshore Sand Resources in Northern Maryland Shoal Fields (Conkwright, et al, 2000)
    Vibracoring was contracted to Alpine Seismic Surveys, Inc. of Norwood, NJ. Alpine provide the 27-meter R/V Atlantic Twin for the work. An Alpine 271 B Pneumatic vibracore drill rig was outfitted to take 6 meter by 9.2 centimeter diameter cellulose butyrate-lined vibracores. Textural parameters were analyzed by Maryland Geological Survey. Textural analysis procedure is detailed in Kerhin and others (1988). Sediment samples were first treated with 10% solution of hydrochloric acid to remove carbonate material such as shells and then treated with a 6% or 15% solution of hydrogen peroxide to remove organic material. The samples were then passed through a 63-micron mesh sieve, followed by a 2-mm sieve, separating sands from mud and gravel fractions. Mud fractions were analyzed using a pipette technique to determine silt and clay contents. Weights of the sand, silt and clay fractions were converted to weight percentages. Sediments were categorized according to Shepard's (1954) classification based on percent sand, silt and clay components. Sand fractions were analyzed using a rapid sediment analyzer (RSA) (Halka and others, 1980). The RSA technique measured cumulative weight in ¼k (phi) intervals. Data were normalized to a 100% sand distribution, and the method of Folk and Ward (1957) was used to report graphic mean and sorting. When mud contents were less than 5%, grain size analyses were conducted only on the sand fraction. Pipette analyses were used to determine silt and clay content in samples with greater than 5% mud.

  1. How should this data set be cited?

    , 2000, Maryland Geological Survey: Offshore Sand Resources in Northern Maryland Shoal Fields (Conkwright, et al, 2000).

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -74.959340
    East_Bounding_Coordinate: -74.902040
    North_Bounding_Coordinate: 38.480560
    South_Bounding_Coordinate: 38.365080

  3. What does it look like?

    MGS00_2.jpg (JPEG)
    Image maps showing extent and distribution of this data layer coverage

  4. Does the data set describe conditions during a particular time period?

    Calendar_Date: 2000
    Currentness_Reference: publication date

  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?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • Entity point (504)

    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 0.000000. Longitudes are given to the nearest 0.000000. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.400000.
      The flattening of the ellipsoid used is 1/294.978698.

  7. How does the data set describe geographic features?


    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Feature geometry. (Source: ESRI)

    Coordinates defining the features.





    The following fields were entered into usSEABED: SFS data: Core ID:Latitude1:Longitude 1:Northing2:Easting2:Depth3:Sample :Interval:Interval:Sample TXG data: Mean:Sorting:Skewness:Kurtosis LTH data: SHEPARD'S CLASS TXR data: Top(cm):Bottom(cm):Depth (altitude): Gravel%:Sand%:Silt%:Clay%:Mud%

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?

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

Why was the data set created?

Offshore sand resource assessment

How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

    (process 1 of 2)
    Data was downloaded from the online publication.

    Person who carried out this activity:

    Chris Jenkins
    Institute of Arctic & Alpine Research (INSTAAR) University of Colorado at Boulder
    1560 30th Street
    Boulder, CO 80309-0450

    (303) 492-6387 (voice)
    (303) 492-6388 (FAX)

    (process 2 of 2)
    Digital data were checked, formatted to dbSEABED input format, then processed using dbSEABED software to produce a range of output formats. The processing contained quality checking that may have declined to pass faulty or suspect data to outputs.

    Person who carried out this activity:

    Chris Jenkins
    Institute of Arctic & Alpine Research (INSTAAR) University of Colorado at Boulder
    1560 30th Street
    Boulder, CO 80309-0450

    (303) 492-6387 (voice)
    (303) 492-6388 (FAX)

  3. What similar or related data should the user be aware of?

    Conkwright, Robert D. , Williams, Christopher P. , and Christiansen, Lizet B. , March 2000, Offshore Sand Resources in Northern Maryland Shoal Fields: COASTAL AND ESTUARINE GEOLOGY FILE REPORT NO. 00-2, Maryland Geological Survey.

    Online Links:

    Submitted to Roger Amato, Contracting Officer's Technical Representative, U.S. Department of the Interior, Minerals Management Service in partial fulfillment of Contract #14-35-0001-30769

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

  1. How well have the observations been checked?

  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?

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

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: None.

  1. Who distributes the data set?[Distributor contact information not provided.]

  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 this data set has been used by the U.S. Geological Survey (USGS), no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and/or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Trade, firm, or product names and other references to non-USGS products and services are provided for information only and do not constitute endorsement or warranty, express or implied, by the USGS, USDOI, or U.S. Government, as to their suitability, content, usefulness, functioning, completeness, or accuracy

  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 25-May-2005
Last Reviewed: 04-May-2005

Metadata author:
Jamey Reid
U.S. Geological Survey
IT Specialist (Data Management)
384 Woods Hole Rd.
Woods Hole, MA 02543-1598

(508) 548-8700 x2204 (voice)
(508) 457-2310 (FAX)

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

Metadata extensions used:

Generated by mp version 2.7.33 on Wed May 25 13:33:01 2005