Sea floor responses to hydrocarbon seeps, Louisiana continental slope

H. H. Roberts, Louisiana State University
P. Aharon, Louisiana State University
R. Carney, Louisiana State University
J. Larkin, Louisiana State University
R. Sassen, BP America, Inc.

Abstract

Observations and samples from research submersible dives confirm that brines, crude oil, fluid mud, and gases are common seep products. Through this mechanism a unique interplay of geochemical, geologic, and biological processes resulting in unusual sea floor features ranging from carbonate-rich nodular sediments to mounds with tens of meters relief. Stable carbon isotopes occluded in the carbonates provide a permanent imprint that links these authigenic carbonates to by-products of microbial breakdown of crude oil and gas. Recent DSV ALVIN dives confirm that hydrocarbon seeps and their accompanying chemosynthetic communities and authigenic carbonate mounds occur over the entire depth range of the slope. © 1990 Springer-Verlag New York Inc.