T169 Aeolian Systems in Time and Space (Posters)

Tuesday, 17 October 2023
8:00 AM - 5:30 PM
Hall B

TEXTURAL CHARACTERIZATION AND AGE CONTROL OF CLAY DUNES ON THE RIO GRANDE DELTA

Paper number: T169-1
Program: Technical Sessions
Time: 8:00 AM – 5:30 PM

Authors

Abstract

Clay dunes are unique eolian landforms that differ from other types of dunes by their large percentage of clay. While initially described in South Texas, recent work has also identified them in Australia, Africa, and China. This work focuses on the clay dunes located on the Rio Grande Delta sub-humid regions of the coastal lagoons in Texas, specifically on the Rio Grande River to Corpus Christi. Locally known as lomas, these dunes form elevated landforms within the otherwise flat Delta plain, resulting from the accumulation of fine-grained intertidal sediments transported by the prevailing Southeasterly winds. The lomas support endemic plant assemblages and provide habitat for wildlife species, including the endangered ocelot (Leopardus pardalis albescens). Despite being geologically rare and ecologically important, the clay dunes in the Rio Grande Delta remain poorly understood; basic questions regarding their age, rates of accretion, and the role of burrowing animals in the adjacent tidal plains remain unanswered. Here we present the first textural characterization and age control of a large dune exposed by State Highway 48, which traverses the delta. We use grain size analysis, loss-on-ignition, x-ray-fluorescence, and radiocarbon dating to provide constraints on the timing formation. The outcomes of this study will enhance the geological understanding of clay dunes and contribute to their preservation.

Geological Society of America Abstracts with Programs. Vol. 55, No. 6

doi: 10.1130/abs/2023AM-389856

© Copyright 2023 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.