A program of electrical measurements on unconsolidated marine sediments was started by the geologic oceanographers at Texas A&M University in 1968. It consisted of measuring resistance and spontaneous potential on extruded cores and in situ in the field, and correlating the electrical values with various sediment and geotechnical properties. The present phase of research concentrates on delimiting and defining sediment lithologies using a towed horizontal array. Several combinations and electrode spacings were tried across Heald Bank, off Sabine Pass, Texas. Bottom-water and sediment samples were collected from well-defined submarine lithologies.

Preliminary results indicate that the spontaneous potential is uniformly highest in mud and clay areas. Large variations occur over shelly sands and shell debris. Resistance is largely uniform across Heald Bank, with relative values depending on electrode

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separation. Towed electrical measurements are complementary to high-resolution subbottom profiling.

Sediment samples collected from Heald Bank were placed in a small wooden trough to appraise some of the properties that control the sediments' resistance and spontaneous potential as well as to obtain insight into the relation between depth of measurement with various electrode spacings. The experimental electrical studies show the same spontaneous potential variations as were found over Heald Bank.

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