Recent hurricanes such as Katrina and Ike have reminded policy makers and planners of the susceptibility of coastal communities to natural forces such as storms, climate change, subsidence, and eustatic sea-level rise. Around 2,600 years ago, several estuaries along the Gulf Coast underwent a period of rapid change. The continued debate concerning the nature of sea-level change over the last 5,000 years, coupled with the lack of century-scale records of climate change, leaves the cause of this event unclear. This project will use two methods of sea-level and climate reconstructions not previously used in Gulf of Mexico studies to provide tighter constraints on the sea-level and climate history of the northwestern Gulf of Mexico over the last 5,000. This new data will help determine if the reorganization of the Gulf Coast estuaries was caused by a change in climate or an increase in the rate of sea-level rise 2,600 years ago. In addition to determining the cause of this event, these new records will provide tighter constraints on the background rates of sea-level rise within the Gulf of Mexico, which may provide some new insights into the amount of subsidence that is occurring along this coastline. The new data will also provide a longer record of century-scale drought than currently exists for the south-central USA. This project supports one graduate and one undergraduate student who will help conduct this research.