Investigation of Changing Wind Energy on the Evolution of Copanobay, Texas

Abstract

Over 123 km of high-resolution 2-D seismic lines and 6 sediment cores up to 16 m in length were collected from Copano Bay along the northwestern Gulf of Mexico in order to investigate the role wind energy had on the evolution of Copano Bay, Texas over the last 10 ka. Paleo-geographic maps of the bay were constructed with the use of seismic profiles and core data to show how the bay evolved through time. Five environmental changes are observed within Copano Bay over the last 9.6 ka. The largest environmental change occurred at 8.2 ka. At the 8.2 ka event, estimates suggest that the bayhead delta back-stepped about 7.5 km resulting from a sea-level rise of 1.2 m at that time. Using grain-size data from middle-bay deposits, a proxy for wind strength is also produced. The wind strength proxy is correlated with other published paleo-climatic records for the area and a reasonable correlation is found. From the grain-size derived wind strength proxy, it is suggested that Copano Bay experienced its windiest conditions of the past 8.2 ky from 5.2 to 4.1 ka. Wind is a dominant force regulating estuarine sedimentary processes. However, grain-size frequency curves at recognized environmental changes within middle-bay deposits do not show evidence that environmental changes were brought on by increases in wind energy.