Maryland Department of Natural Resources

Data Sets of the Surficial Sediment Distribution of Chesapeake Bay, Maryland

contact: Bob Conkwright (bconkwright@dnr.state.md.us)

Data Set Title:   
  
Chesapeake Bay Earth Science Study (CBESS):
Physical Properties of Surficial Sediments, Chesapeake Bay, Maryland

     In 1976, the coastal geologists of the Maryland Geological Survey began a comprehensive survey of Bay bottom sediments, known as the Chesapeake Bay Earth Science Study (CBESS). With funding from the State of Maryland and the U.S. Environmental Protection Agency, we collected over 4,000 surface sediment samples from the Bay in Maryland - one sample every square kilometer. (Scientists at the Virginia Institute of Marine Science did the same for the Bay in Virginia.) Laboratory technicians analyzed the samples for grain size (the proportions of sand-, silt-, and clay-sized particles) as well as water, carbon, and sulfur content.

     These data sets contain all of the physical and geochemical measurements made on the CBESS sediment samples, including grain size, water content, bulk density, total and organic carbon content, and sulfur content. Two data set formats are available for download: 

      The flat-file data table uses standard comma-delimited, ASCII format. The first row in the data table contains the descriptive headers for each column. The ESRI shape files were compiled in ArcGIS 8.3 and require the use of Arc 8.3, or later, products. The ESRI shape files can be viewed with the free ESRI ArcReader 8.3. Data sets and the CBESS project itself have been exhaustively documented using a federal metadata standard. The metadata contains detailed information on sample collection and analysis techniques. That documentation is available in two formats - ASCII and WordPerfect 6. An interactive map for this database is available on our website. You can view the sediment distribution map constructed from this data set. Follow the VIEW: MAP link at the bottom of this page to use the interactive map.

       A brief metadata summary is presented here, but is not intended to replace the complete metadata text.

METADATA SUMMARY

Description: This is a data table, in comma-delimited, ASCII format, which contains information about selected physical properties, particularly grain size, of 4,255 surficial sediment samples from the Chesapeake Bay in Maryland. Samples were collected on a 1-km grid by the Maryland Geological Survey between June 1976 and August 1984. 
Purpose: One component of the Chesapeake Bay Earth Science Study (CBESS) was a baseline inventory of Chesapeake Bay bottom sediments, particularly of those properties or features (e.g. sediment type, water content, sulfur content, carbon content) that affect the distribution of toxic substances. The project, funded by the U.S. Environmental Protection Agency, was a cooperative effort between the states of Maryland and Virginia. The Maryland Geological Survey and the Virginia Institute of Marine Science were responsible for sampling and analyzing sediments deposited in the waters of their respective states. Information contained in this data set is for Maryland only.
 Custodian: Maryland Department of Natural Resources/Maryland Geological Survey
Contact: Jeff Halka - (410) 554-5543; e-mail: jhalka@mgs.md.gov
Date: Sediment samples collected between June 1976 and August 1984
Data Type: Data table
Format: Comma-delimited ASCII
Geographic Area: Main stem of the Chesapeake Bay, Maryland; Eastern Bay; Choptank River; Tangier Sound
Coordinate System: Latitude/Longitude, NAD27, decimal degrees
Attributes: Grain size distribution between -1 and 14 phi, in 1/4 or 1/3 phi intervals; summary grain size statistics (graphic and moment measures); water depth; water content; bulk density; carbon content; sulfur content (See metadata)
Detailed Metadata: Yes - Follow this link


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