Modern Shoreface and Inner-Shelf Storm Deposits Off the East Texas Coast, Gulf of Mexico

Abstract

ABSTRACT The modern shoreface and inner-shelf sediments off the east Texas coast on the Gulf of Mexico were examined using sediment cores and high-resolution seismic data. Low sediment input and low effective accommodation space resulted in the overall thinness of the modern marine sediment cover in the region. Erosion on the inner shelf during historic ( 100 yr) times produced patches of sand in a predominantly mud-dominated environment. Storm beds are scarce on the inner shelf. The shoreface succession off Galveston Island is characterized by offshore-directed crosscutting storm channels of varying sizes. The existence of these channels and the relatively high frequency of storms and hurricanes that have affected the region during historical imes are inconsistent with the paucity of storm deposits on the inner shelf. The offshore-directed channelized flows may have been prevented from going beyond the shoreface by strong along-shelf storm currents that impinged on the shoreface. In contrast to the storm record on the east Texas shelf, the central Texas shelf shows a greater frequency of and more laterally persistent storm sand beds due to greater effective accommodation space and higher sediment supply there.