Since the beginning of the Deep Sea Drilling Project more than 10 years ago, organic geochemical studies have been undertaken on almost 2,000 sediment samples from beneath the ocean floor. These studies have provided fundamental information regarding the distribution of carbon in oceanic sediments and have yielded a better understanding of the processes that alter and transform organic matter in the marine environment. Of particular practical importance have been those investigations directed toward the occurrence of liquid and gaseous hydrocarbons in sediment of the continental margins and ocean basins; however, work has not been specifically directed to finding oil and gas. Instead, such discoveries have been purposely avoided, and information about possible occurrences of petroleum has been extrapolated from studies of anoxic basins, such as the Carioca Trench and the Black Sea, and from continental-margin sediments such as those off Norway, northern Africa, and southwest Africa. It is evident that significant concentrations of organic matter are sequestered in certain marine sediments, and it appears that much of this organic matter has come initially from the continents. Studies of the continental rise off Morocco show that organic material is undergoing diagenetic processes leading to petroleum. The organic geochemical conditions for petroleum formation, therefore, are present in the outer continental margins, but it remains to be determined if the geologic settings there are favorable for petroleum accumulations.

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