282-4 Depositional Systems and Holocene Evolution of Baffin Bay, Texas

See more from this Division: Topical Sessions
See more from this Session: Response of Coastal Environments to Accelerated Sea Level Rise

Wednesday, 8 October 2008: 8:45 AM
George R. Brown Convention Center, General Assembly Theater Hall A

Alexander R. Simms1, Niranjan Aryal2, Lauren Miller1, Yusuke Yokoyama3 and Hiroyuki Matsuzaki3, (1)Boone Pickens School of Geology, Oklahoma State University, Stillwater, OK
(2)Schlumberger, New Orleans, LA
(3)Department of Earth and Planetary Sciences, Univ of Tokyo, Tokyo, Japan
Abstract:
Using over 65 km of high-resolution seismic profiles and 10 cores from Baffin Bay, Texas we present a depositional and evolutionary model for an estuary formed in a semi-arid climate. Baffin Bay is the flooded incised valley of San Fernando, Los Olmos, and Petronila Creeks. It is currently situated in a semi-arid climate and isolated from the open Gulf of Mexico by Padre Island. As a result, the salinities within Baffin Bay vary widely but average around 50-60 ppt. Baffin Bay initially flooded before 8 ka, most likely around 9.5 ka. During the early part of its Holocene history, it was less restricted and/or more humid than today as evidenced by oysters (Crassostrea virginica) and a well-developed fluvial system, neither of which are found in the bay system today. Around 8.0 ka, the estuary experienced a rapid landward expansion as evidenced by sharp contacts in marine cores and seismic profiles. This event most likely resulted from a small-amplitude global sea-level rise event associated with the drainage of Lake Agassiz-Ojibway. By ~5 ka, the estuary became more restricted and/or drier, similar to the conditions prevalent today. As a result of its isolation and semi-arid setting, the bay has developed some depositional elements different from the other estuaries of Gulf of Mexico over the last 5 ka. These include several “fetch-limited” barrier islands and spits composed almost exclusively of shell hash, serpulid worm-tube reefs, and prograding mud flats covered in algal mats.

See more from this Division: Topical Sessions
See more from this Session: Response of Coastal Environments to Accelerated Sea Level Rise