Texas Barriers

Abstract

The modern configuration of the Texas coast reflects competition between fluvial-deltaic sedimentation and reworking by marine processes that produce a dominant westerly flow in the northern Gulf of Mexico (LeBlanc and Hodgson 1959). This westerly flow and the regional distribution of barrier islands led some early workers to conclude that Texas barrier islands were deposited by littoral drift reworked from the Mississippi River. More recent geologic studies have shown that Texas barriers are reworked deltaic deposits but of Texas coastal plain rivers rather than the Mississippi. Erosion of relatively stable deltaic headlands, winnowing of the eroded material, and deposition of the coarse fraction in interdeltaic embayments are the result of wave and current dominance over fluvial supply. An important geologic consequence of the disequilibrium in forces is that thickest deposits of well-sorted barrier sand are located the greatest distance from any fluvial source.