Middle Holocene Sea-Level Change and Coastal Response, Texas Gulf Coast

University Of Nebraska-Lincoln, Lincoln NE

Investigators

Abstract

Recent NSF-sponsored research has resulted in a new model for middle Holocene sea-level change along the Texas Gulf Coast. This model suggests sea level reached present elevations 6800 years ago, and was slightly higher than modern for 2000 years after that. This view contrasts sharply with traditional interpretations, as well as recent and ongoing work by another research group, which would place sea level 6-10 m below present at that time, with present sea level not reached until 3000 years ago. This new phase of research will test these alternative models through documentation of middle Holocene sea-level change and the response of coastal geomorphic systems. Geomorphological, sedimentological, micropaleontological, and geochronological techniques will be used to examine a series of newly-recognized landforms that may hold the key to testing these alternative views of sea-level change and coastal evolution. The Texas Gulf Coast has long served as a natural laboratory for the study of coastal processes and landforms and their evolution in response to post-glacial sea-level rise. Several well-known models for coastal landscape evolution have been developed here, but within the context of the traditional view of continued sea-level rise until 3000 years ago. Documentation of a middle Holocene highstand would have significant implications for interpretations of coastal landscape evolution at the regional scale, as well as global-scale ice volume and sea-level signatures. Moreover, the petrochemical, shipping, fisheries, and tourism industries are linked to the present distribution of environments and resources, so past and future sea level changes in this area are of more than academic interest. Documentation of a higher sea-level position, and attendant coastal response, may provide an analog for sea-level rise scenarios that have been predicted for the near future due to anthropogenic and natural climate changes.