Coupling geological concepts with historical data sets in a MIS framework to prospect for beach-compatible sands on the inner continental shelf: experience on the eastern Texas gulf coast

Chronic erosion of beaches along the eastern Texas barrier island coast is increasingly mitigated by renourishment efforts that periodically place large volumes of sand onshore. Location of beach-quality sands on the inner continental shelf is challenged in an environment where terrestrial rivers deposit fluvial sediments in back bays and lagoons instead of offshore and by shelf areas that are dominated by muds. The search for beach-quality sands thus requires understanding of the coastal geological framework and morphodynamic processes that accompanied late Quaternary evolution in the northern Gulf of Mexico. The occurrence of surficial sand deposits as positive bathymetric features on the seafloor (ridges, shoals, banks) and presence of sands buried in paleovalley (drowned channels) infill sequences makes for complicated search procedures that must accurately differentiate a range of sedimentary settings by geophysical and geotechnical surveys. Compilation of vast amounts of data from historical core logs and newly acquired information in a marine information system (MIS) permits spatial analyses in a format that is compatible with development of a sand search model. The resulting differentiated investigative sand-search methods, that comprise part of the Texas Sand Search Model (TSSM), are able to target potential borrow areas in ebb-tidal shoals, low-relief ridge deposits, high-relief banks, and in mud-covered paleovalley sequences.