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Petroleum geochemical and geologic studies were carried out on the COST GE-1 well (Southeast Georgia Embayment), and on the Atlantic Margin Coring Project (AMCOR) core 6004 on the Florida-Hatteras slope. Mud additives contaminated some of the COST GE-1 samples, but by analyzing several duplicate handpicked sample suites the effect, although not totally removed, was minimized.

In the COST well, the Tertiary shale-chalk-limestone section to a depth of approximately 1,088 m contains very small quantities of indigenous, biogenic hydrocarbons that are not believed to have had a thermal-chemical history. Upper Cretaceous rocks (Maestrichtian, Campanian, Santonian, Coniacian, and Turonian) from 1,088 to 1,814 m consist of gray, calcareous deep-water shales that contain the most organic-rich intervals in the well which are composed of thermally immature, amorphous, hydrogen-rich algal marine kerogens. If these Upper Cretaceous rocks were buried more deeply or found in a region of higher thermal gradient, they could be significant potential oil and gas source rocks. The Lower Cretaceous sedimentary rocks from 1,814 to 2,700 m are dominantly of continental origin wi h intercalated marine carbonate and sand units that contain very small amounts of terrestrial organic matter (less than 0.1% organic carbon). Although the kerogen in these rocks is of marginal thermal maturity, it promises little as a potential petroleum or natural-gas source.

Sediments in the AMCOR hole 6004 range from Holocene to Upper Cretaceous and are of a predominantly outer shelf-upper slope depositional character. The hydrocarbon and fatty-acid distributions and molecular compositions are typical of marine biogenic sources that are thermally immature with regard to petroleum generation. The organic geochemistry of Paleocene sediments taken from the AMCOR core 6004 may reflect the influence of erosion by the ancestral Gulf Stream.

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