THE ROLE OF ANTECEDENT TOPOGRAPHY IN SHAPING COASTAL CHANGE CAUSED BY SEA LEVEL RISE

The link between global warming and sea level rise has sparked a rejuvenated interest in determining the effects of sea level rise on coastal environments. Recent studies have focused on using the past record of Holocene sea level changes as a way of predicting the impact of future sea level rise on coastal environments. While undertaking such a study of the coastal environments of Corpus Christi Bay in Central Texas, we found that antecedent topography had a dramatic effect on the evolution of the bay. During the last sea level fall (OIS 5-2), terraces formed in the paleo-valley of the Nueces River. As sea level rose (OIS 1), the Nueces valley was flooded to form Corpus Christi Bay. High-resolution seismic profiles and sediment cores, reveal that the flooding of fluvial terraces resulted in abrupt changes in the bay. Such abrupt changes include the formation or destruction of spits, oyster reefs, tidal delta complexes, and bayhead deltas, including their incipient wetlands. Thus, flooding of terraces acts to punctuate the effects of sea level rise within estuaries and bays.