The late Pleistocene Ingleside Barrier Trend, Texas and Louisiana
- JPEG 2000 image
- Areal Extent of Live Oak Barrier Trend
- JPEG 2000 image
- Geological map - Smith Point Pine Island Area, Texas
Graf, Claus Heinrich
Lankford, Robert R.
Master of Arts
Geomorphic studies of the Gulf Coastal Plain show the existence of an interrupted trend of elongate ridges, which extends from southwest Texas into western Louisiana. Sediment samples from shallow borings on the top and flanks of these ridges were studied in terms of their mechanical properties and paleontological, characteristics. Heavy and light mineral constituents were studied in selected samples. Deep weathering is the main post-depositional alteration suffered by these sediments and products of soil-forming processes- complicate the studies. Results show that the high ridges are composed of fine and very fine sands in most areas and of very fine sands and silts in the easternmost segment. They were deposited as barriers, under generally similar conditions as the present barrier islands of the Gulf of Mexico. The trend is referred to as "Ingleside Barrier Trend", The barrier sands interfinger with near-shore deposits to the south and with bay sediments to the north, although locally, the upper sands are time equivalents to deltaic and alluvial clays, which thinly cover the bay and near-shore deposits. Regional subsidence of the Gulf Coast Geosyncline and regional uplift of the inland areas are responsible for the present topographic position of the Late-Pleistocene, Ingleside Barrier Trend. In certain areas, local movements are superimposed on the regional deformations. Paleontological studies proved helpful in outlining paleoenvironments, but failed to be of value for age determinations. Local age data, as well as regional paleotemperature studies were used to establish a correlation with glacial events. It was concluded, that the Ingleside Barrier Trend formed during an early, unnamed interstadial of the Wisconsin Glaciation, when sea level was 10 to 20 feet higher than the present, approximately, 55, 000 yrs. B. P. The trend probably correlates With similar systems around the Gulf of Mexico, as well as along the Atlantic Coastal Plain.