Normal sediment-distribution maps present the lithologic characteristics of only the upper 4-6 in. of the sedimentary column.

Cores collected from any area commonly reveal considerable changes in lithologic character through the thickness of the beds which are cored. Such variations can be expressed in vertical sections or in fence diagrams. Information concerning the upper sediment column to a depth of at least 30 ft is important for studies on sediment transport and deposition, basin filling, geotechnical properties, placing of laboratories on the sea bottom, salvaging sunken objects, acoustical measurements, and interpretation of high-frequency, shallow-penetration, and continuous seismic-reflection profiling.

"Standard patterns" have been determined from samples collected in long piston cores which penetrated different lithologic units and successions. The new sediment-distribution map constructed on the basis of the 30-ft cores shows the distribution of these standard patterns and thus reveals the sedimentary characteristics of the upper 30 ft. The patterns can be portrayed by colors, shades, and symbols, or combinations.

Other properties, such as geotechnical characteristics, can be added to the standards of the map or can be superimposed on the standard presentation.

The main divisions of the sediment-distribution map correspond to the boundaries of the physiographic provinces of the Gulf of Mexico.

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