The USGS reports finding the first concentrations of hydrocarbons off the northern California coast in a sea floor sample taken about 40 km. east of Eureka. Analyzed aboard RV Sea Sounder, the 1.6-m gravity core was found to contain anomalously high amounts of natural gases, ranging from methane to butane.
The sample was collected and examined by Michael E. Field, Keith A. Kvenvolden, and Samuel H. Clarke, Jr. It was taken in November from a small pond of sediment near the crest of a knoll about 500 m below the sea surface on the Eel Plateau. The knoll, say the scientists, is a diapir-like structure similar in some respects to the salt domes in the petroleum regions of Texas and the Gulf of Mexico.