Latest Quaternary Regional Sedimentation Processes in the U.S. Gulf of Mexico Exclusive Economic Zone (EEZ), #11201 (2019)

Interpretation of very high-resolution (3.5 kHz) seismic facies reveals that turbidity-current, mass-transport (MTD), and bottom-current depositional processes have all contributed to the regional sediment distribution throughout the U.S. Exclusive Economic Zone (EEZ) in the northern Gulf of Mexico. Piston cores from these deposits confirm the interpretations of these processes and show that most were deposited during the Last Glacial sea-level lowstand. The eastern half of the EEZ is dominated by the Mississippi Submarine Fan, which is composed of mud-rich channel-levee complexes on the upper and middle fan, and sandy lobes on the lower fan. Although MTDs were previously mapped from the east side of the fan, our 3.5 kHz data reveals the total distribution of MTDs across the western side. The 3.5 kHz data also shows seismic facies consistent with very sandy deposits throughout the lower fan. In contrast, the western EEZ is dominated by intraslope mini-basin systems, and turbidity currents have deposited large volumes of sands into these basins canyons.