DAVIDOFF, ANDREW J., Texas A&M University, Department of Geology, College Station, TX

ABSTRACT: Three Basin Model for Central East Texas: Basement Structure and Sedimentary Fill

The East Texas region has traditionally been divided into two major provinces. Regional mapping with deep well control and seismic indicate a three-basin model is more appropriate. This model is based on the location of deep basement structures, distribution of Louann Salt, and timing of initial sedimentation. Major basins include, from north to south, the East Texas basin, Brazos basin and Houston embayment.

The Houston arch separates the East Texas and Brazos basins. It was atopographic high throughout the Callovian, separating the Louann Salt of the two basins and blocking southward progradation of the Norphlet sandstone. From Oxfordian to Kimmeridgian, shallow-water carbonates of the Louark Group were deposited in the East Texas basin. The Brazos basin to the south was starved while platform margin reefs were localized along the Houston arch. Sedimentation within the Brazos basin began with the influx of Cotton Valley clastics during Tithonian.

The Angelina-Grimes terrace separates the Brazos basin and Houston embayment. This feature was structurally positive until the end of the Cretaceous, and separates the Louann Salt of the two basins. From Berremian through Cenomanian shallow-water carbonates of the Sligo and Edwards formations were deposited in the East Texas and Brazos basins. The Houston embayment to the south was starved while platform margin reefs were localized along the southern edge of the terrace. Sedimentation within the Houston embayment began in the Paleocene with the influx of the Wilcox clastics.

The Brazos basin is relatively underdrilled compared to the East Texas basin and Houston embayment. Recognition of the major basement structures in central East Texas and their effect on the overlying sediments should provide refined exploration models and new opportunities.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.