Rotary-drill cores from the Matagorda and Lavaca estuary complex sampled six distinct lithofacies, and high-resolution seismic data reveal four main seismic facies. The facies architecture of the bay indicates a history of Holocene flooding punctuated by major landward shifts in estuarine environments. Radiocarbon ages help to constrain the rate and timing of these flooding events and indicate significant reorganization of the estuarine environments at a decadal to century time scale.

The Holocene evolution of the Matagorda and Lavaca estuary complex began ca. 11,600 yr B.P. with initial flooding of the portion of the ancestral Lavaca River incised valley that is...