The Orca Basin is a mid-slope, silled, mini-basin in the northern Gulf of Mexico some 300 km southwest of the Mississippi River mouth on the Louisiana continental slope.
[1] Gas hydrates were detected in a number of cores collected in the Orca basin during Leg 96 of the Deep Sea Drilling Program (DSDP).
[3] The Orca Basin is important in understanding glacial and deglacial changes, including the history of meltwater flows from the Laurentide Ice Sheet, that have affected North America and the Gulf of Mexico.
[5] The sediments that fill the Orca Basin contain an important record of the paleoenvironment and paleo-oceanology of the Louisiana continental slope south of the Mississippi River Delta for at least the last 25,000 years.
[8][9] In addition, the only recorded recovery of gas hydrates in the Gulf of Mexico from depths greater than 66 fbsf (20 mbsf) occurred at DSDP Site 618 in the Orca Basin.
Below depths of 2,225 metres (7,300 ft), detectable dissolved sulfide increases and indicates that bacterial sulfate reduction is the primary method for organic matter degradation.