MIDDLE-UPPER ALBIAN SEQUENCE STRATIGRAPHY INTERIOR SHELF TO SHELF MARGIN, COMANCHE SHELF, TEXAS

This project is designed to authenticate one of two hypotheses existing for Comanchean stratal correlation of subsurface intervals in the Gulf Coast Basin of East Texas to intervals cropping out in the Pecos River Valley in West Texas. Rose (1972) interprets correlation of the informal regional dense marker bed (RDMB) to the base of the Washita-age Kiamichi Formation in Travis and Kerr Counties. Waite et al. (2007) correlates the RDMB within the Fredericksburg-age Edwards Formation outcrops.

Precise geologic correlation within the Comanchean Series will be completed by utilizing several methods including interpretation of detailed petrographic data, isotope values and redox results. Foraminifera and rudist bivalves provide control for age assessment of stratigraphic units. Implications for subaerial exposure will be tested through analysis of geochemical data on the upper contact of the Albian Fort Terrett Formation of the Fredericksburg Group. Geochemical testing for evidence of oceanic anoxia within Lower Washita shale intervals will provide data for comparison to globally correlative intervals that have previously been defined as indicators of OAE 1c.

Compiled biostratigraphic and chemostratigraphic evidence will be used to more precisely correlate measured sections cropping out in Crockett County with subsurface sections from Person Field in Karnes County, Texas. This project builds upon interpretations of ages and origins of the Lower Cretaceous carbonate Comanche Shelf made by recent supported and accepted graduate student research. Additionally, significant published contributions to the lithostratigraphy and biostratigraphy of Texas Cretaceous carbonates will provide further insight and a basis for geologic correlation. Integration of petrographic and geochemical data analysis with interpreted facies and diagenetic conditions will allow detailed sequence stratigraphic correlation of Albian-age Texas carbonates from the Gulf Coast to the Pecos River, which is essential for the future development and interpretation of the Early Cretaceous Comanche Shelf and for understanding accurate hydrocarbon models in Texas.