Sequence Correlation of the Mid-Comanche Series, South Texas Region

Dena S. Chenault¹ and Lance L. Lambert^2
1Portage Environmental, Inc., 901 N.E. Loop 410, Suite 700, San Antonio, Texas 78209
²The University of Texas at San Antonio, Department of Earth and Environmental Science, 6900 N. Loop 1604 W., San Antonio, Texas 78249-0663

Previous studies of the middle Comanche Series of south Texas have defined different stratigraphic units in each of four paleodepositional settings, which has impeded regional correlation and synthesis. The Edwards Group occurs across two distinct shelf areas, the San Marcos Platform and the Central Texas Platform. The Devil's River Formation encompasses a formally undivided shelf margin with common reef development, generally referred to the Devil's River Trend. The Devil's River Trend separates the shelf platforms from the epicontinental Maverick Basin. The middle Comanche Series comprises two high-frequency sequences that provide for regional correlation. Each high-frequency sequence is divided into transgressive and highstand systems tracts, with the lowstand systems usually absent from the area of study. The lower high-frequency sequence includes the Kainer Formation (San Marcos Platform), the Fort Terrett Formation (Central Texas Platform), the lower Devil's River Formation, and the West Nueces and lower McKnight formations (Maverick Basin). The upper high-frequency sequence includes the Person Formation (San Marcos Platform), the Segovia Formation (Central Texas Platform), the upper Devil's River Formation, and the middle and upper McKnight and Salmon Peak formations (Maverick Basin).

AAPG Search and Discovery Article #90080©2005 GCAGS 55th Annual Convention, New Orleans, Louisiana