DETAILED TEXTURE AND HEAVY MINERALOGY OF RECENT SANDS ALONG THE NORTHEASTERN TEXAS GULF COAST AND A RESULTING MODEL FOR BARRIER FORMATION
COLE HOERSTER, MARY LOU
Doctor of Philosophy
Numerous textural and heavy mineralogical analyses have been performed on sand samples from the northeastern Texas Gulf coastal region. Analyses of local point-bar samples result in the delineation of major river and sources, with average histograms of grain-size data showing combinations of discrete modes characteristic of each river. Similar study of area coastal sands allows distinction of river, beach, and fluvial- and wave-dominated deltaic sands on the basis of texture. Kyanite/garnet/hornblend + pyroxene ratios are an excellent criterion for evaluating source contributions to the coast. Combining approximated age (radiocarbon) dates and heavy-mineral ratios results in the delineation of two distinct sand types. Spatial relationships between the two are used to develop a model for barrier formation. The model is then compared with previous models, applied to local problems of beach erosion, and discussed with regard to the ancient record.