Architecture of from Incised Valley Filled within a Semiarid Climate: Baffin Bay, Texas

Simms, Alexander R.¹; Aryal, Niranjan ³; Miller, Lauren ¹; Yokoyama, Yusuke ^2
1 Boone Pickens School of Geology, Oklahoma State University, Stillwater, OK.
² Department of Earth and Planetary Sciences, University of Tokyo, Tokyo, Japan.
³ Schlumberger, Houston, TX.

Incised valleys are an important element within many conventional hydrocarbon systems and preserve an important archive of environmental changes within the rock record. As a result, many studies have been conducted in order to better understand the variability that exists within the fill of incised valleys. To date most of these studies have focused on the impact of physical processes (e.g. tides, waves,rivers) in accounting for the variability that exists within the valley fills. However, few studies have looked at the importance of climatic variability and its impact on the sedimentary architecture of incised valleys. Using 65-km of new high-resolution seismic data, 18 new cores reaching depths of 17.7 m and published data, we examine the sedimentary facies within the Late Quaternary/Holocene Baffin Bay incised valley along the semi-arid south Texas coast. Due to the near absence of freshwater inflow, its isolation from the open Gulf of Mexico by Padre Island, and its semi-arid climatic setting, Baffin Bay, Texas has developed an unusual set of depositional environments. These unusual depositional environments include ooilitic beaches, “fetch-limited” spits and barrier islands, serpulid worm-tube reefs, and prograding mud flats. These depositional environments also provide an important record of climatic and sea-level changes through the Holocene. From these deposits several criteria are suggested for identifying incised valleys deposited within semi-arid and arid climate settings.

AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009