The preservation potential of shoreface deposits is variable along the Texas coast. From Bolivar Penninsula to North Padre Island, 410 sediment cores and 3000 km of seismic data were collected to understand the factors that control coastal lithosome preservation. On the east Texas shelf, lower shoreface deposits are preserved in the transgressive systems tract within sand banks located adjacent to and over the Trinity/Sabine incised fluvial valley. Modern shoreface profiles across east Texas are steep and show isolated storm reworked sand lenses in marine mud lying above the transgressive ravinement surface. In the Brazos/Colorado area of the east Texas shelf, no shoreface sands are preserved. The low preservation potential is due in part to longshore current transport of sands toward the central Texas coast. Along the central Texas area of the shelf, from Matagorda Penninsula to North Padre Island, there is a high preservation potential of thick marine sheet sands deposited during the last glacial eustatic highstand. A similar sandy facies is observed in older highstand sequences on the shelf. Modern central Texas shoreface profiles show low gradients, are currently prograding, and are in excess of 5 meters thick. Variability in preservation potential of shoreface sands along the Texas coast can be attributed to sediment input, longshore current transport, storm reworking, and rates of transgression. Ongoing research focuses on determining the lateral distribution and sand-prone nature of highstand deposits along the central Texas shoreface.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas