Introduction to the Gulf of Maine Contaminated Sediments Database

Texture Table

The Texture Table in the Gulf of Maine Database is an Excel 4.0 document which requires 2.2 MB of hard disk space and contains information on over 4000 samples. The table contains each sample's Unique Identification Number (Unique ID) and source or reference as well as 26 fields pertaining to laboratory information and 100 analysis fields (See Parameter Listing). The data, which are not reported in units that are common to all samples, may be presented in more than one form, e.g.: as both phi class frequencies and as cumulative frequencies.

The user should read all data entry, methodology, and comment columns in order to ascertain how the data were originally generated.  Whenever possible grain size data was converted to one of the most basic formats, units for percentage gravel, sand, silt, and clay. The various methods that are used to determine particle size return slightly different results; for example, the U.S. Army Corps of Engineers' sieve size measurements are not exactly equivalent to phi size measurements. Also, out of the samples with texture data, only about 45% had either fine or coarse fraction methods reported in the original document. Consequently, care must be used when comparing these data.

The information in the Texture Table may be used in conjunction with location data from the Station Table to map the distribution of the samples and their concentrations. For illustration purposes, the data has been used to create a pie chart display, and selected  maps are shown here as examples.

View plots and graphs of the texture data.