Natural oil and gas seepage is well known at Coal Oil Point near Santa Barbara, California. A lesser known area of seepage occurs near Point Conception.  Coalescing asphalt mounds with concurrent gas seepage are 10 to 500 m in diameter, as much as 18 m thick, and cover an estimated 8.4 km2 of the seafloor. The volume of asphalt is estimated to be about 27 million m3, the equivalent of 170 million barrels of oil. The largest contiguous area covers about 2 km2, is as much as 10 m thick, and occurs in water depths of 50 to 70 m. The age of the flows is unknown, however the areal extent of the flows coupled with the asphalt volume of currently erupting flows suggest the asphalt complex to be at least hundreds of years old. The parent oil is biodegraded resulting in asphaltic residue and significant production of greenhouse gases.

Natural offshore asphalt seepage in Southern California

243rd National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.