Continuous seismic profiles of a shelf-edge bathymetric prominence in northern Gulf of Mexico
Matthews, Robley K., 1935-
Purdy, Edward G.
Master of Arts
Sparker profiles across a shelf-edge bathymetric prominence located thirty five miles east of the Mississippi Delta provide three dimensional information as to the nature of the prominence and its relation to flanking sediments. The prominence is located at the break in slope between continental shelf and continental slope and rises to 190 feet from a shoreward shelf depth of 230 feet. Sparker profiles reveal the topographic prominence to be underlain by at least 250 feet of unstratified material. Shoreward flank sediments dip away from the prominence five to ten degrees. Seaward flank sediments dip away from the prominence five to twenty degrees. Strata within a proximity of 2,000 feet to the prominence have, in general, greater reflecting efficiency than strata further removed. An unconformity is observed in the shoreward area within the upper eighty Feet of sediment. The sparker data is reviewed in the light of previous interpretations as to the origin of other bathymetric prominences in the Gulf of Mexico. It is tentatively concluded that the subject prominence is the expression of a proHolocene bioherm of at least 250 feet thickness.