Although the mature, supergiant East Texas field on the west flank of the Sabine Uplift has been producing from the Upper Cretaceous (Cenomanian) siliciclastic Woodbine Group for more than 75 years, no modern comprehensive geologic study of it has been completed.

This report summarizes results of the East Texas Waste Isolation (ETWI) program from January 1, 1978, to March 30, 1983. Having an extensive data base, the study comprised 33 different lines of research by 67 scientists and research assistants.

Several microearthquake recording stations were operated as a network in the East Texas Basin beginning in June 1981. At least six certain and two probable earthquakes as well as hundreds of events of undetermined origin were recorded through August 1982.

Post-Aptian strata (younger than 112 ma) in the East Texas Basin were strongly influenced by halokinesis and recorded the evolution associated sate structures.

Lignite deeper than 200 ft (61 m) constitutes about 60 percent of the total lignite resources in Texas. Projections indicate that meeting future demand will require mining this deep-basin lignite.

The Nacatoch Formation of the East Texas Basin is the middle formation of the Navarro Group and consists of marine sandstones and mudstones derived largely from source areas to the northwest, north, and northeast of the East Texas Embayment.

Principal fault systems in the East Texas Basin were examined in terms of their distribution, geometry, displacement history, and possible origins.

Mobilization of the Louann Salt created the present structural configuration in the central part of the East Texas Basin and was the major control on hydrocarbon accumulation in the area. Salt-cored anticlines, turtle-structure anticlines, and salt diapirs were produced by flow of salt.

Eocene stratigraphic units in the East Texas Basin are composed of a thick sedimentary sequence (approximately 2,000 ft [600 m]) of fresh-water aquifers and aquitards covering an area of approximately 15,000 mi2 (51,000 km2).