Anoxic, hypersaline basin in the northern gulf of Mexico.

A 400-square-kilometer depression in the continental slope of the northern Gulf of Mexico (approximately 27 degrees N, 91 degrees W) has been found to contain anoxic, hypersaline ( approximately 250 grams per kilogram) water in the bottom 200 meters. The interface between the brine and overlying seawater acts as a midwater seismic reflector similar to those seen in the Red Sea. The bulk chemical composition of the brine is similar to that from the Red Sea, but differences between the two in both heat content and geomorphological setting indicate different modes of origin.