Episodic flooding of estuarine environments in response to drying climate over the last 6000 years in Baffin Bay, Texas

Abstract

Recent studies along the northwestern Gulf of Mexico document rapid, centennial-scale, landward retreat or back-stepping of estuarine environments up to 20km ca. 8.0ka, 4.8ka, and 2.6ka. If such rapid changes in coastal environments occurred today along the urbanized coast of the Gulf of Mexico major economical and ecological loss would occur. Although the 8.0ka event occurs at a time of increased rates of sea-level rise, the latter two do not; leading to the hypothesis that they may be the result of past climate change. In this study, 121 cores, 4.3km of high-resolution seismic profiles, and 53 radiocarbon dates are utilized to characterize the stratigraphic architecture and constrain the timing of stratigraphic flooding surfaces in the estuarine fill of upper Baffin Bay, Texas over the last 6ky. Five flooding surfaces, which formed between 1.1–1.0ka, 2.7–2.1ka, 3.8–3.0ka, 5.2–4.9ka, and 6.5–5.7ka, occur within error of drying in southern Texas driven by warming in the North Atlantic and recorded in independent paleoclimate archives. We suggest that these flooding surfaces, which occurred when sea-level in the Gulf of Mexico was rising <2mm/yr, were primarily driven by declines in fluvial sediment supply to the coast due to past climate changes.