EXPLORATION OF BURIED PALEOCHANNELS UNDER FOLLET’S ISLAND, TX FOR BEACH RE-NOURISHMENT

Follet’s Island is an eroding shoreline, bounded by Christmas and Drum Bays to the west, San Luis Pass to the north, Freeport Jetties to the south, and the Gulf of Mexico to the east. It lies atop various incised channels created during the Pleistocene that have since been filled with Holocene sediments and overlain with the present day sandy shoreline. CHIRP sub-bottom surveys were conducted in June 2004 both offshore and on the bay-side of Follet’s Island to determine the location and geometry of the incised channels. Several buried channels were located in the bay-side profile, with a few extending across the island to the offshore portion of the surveys. After collection and processing of the sub-bottom data, drilling was carried out to confirm the presence of the channels and to qualitatively determine the grain size distribution of the channel fill. Future work in this area will employ the use of a vibracore to quantify the grain size distribution of the sediment filling the paleochannels. In addition, a deeper penetrating sub-bottom profiler may be applied to image the channels through sandy surface sediments that were not penetrated in the initial surveys. Based on this future data, these buried channels may be mined for sands used in beach re-nourishment of the upper Texas coast.