The objective of this study is to identify major sand trends, which, along with subsurface temperatures and pressures, aid in evaluating the potential of producing geothermal energy from the Frio Formation, Upper Texas Gulf Coast.

The Bureau of Economic Geology has been conducting regional studies of the Frio Formation along the Texas Gulf Coast to evaluate potential geothermal energy from deep, geopressured sandstone reservoirs (Bebout, Dorfman, and Agagu, 1975; Bebout, Agagu, and Dorfman, 1975).

The State of Texas has about 367 miles of open Gulf shoreline, most of it typified by rather broad, sandy beaches and a comparatively mild climate that permits almost year-round use of this recreational resource. All but about 87 miles of the Gulf beach is accessible to the general public.

Three principal depositional systems were defined within the Sparta Formation of Texas using surface and subsurface data: high-constructive delta system in east Texas; strandplain-barrier bar system in central Texas; and high-destructive, wave-dominated delta system in south Texas.

The Paluxy Formation is a stratigraphic unit which is composed of sandstone and shale and extends across the northern part of the East Texas embayment.

Lignite is a rediscovered energy in Texas because lignite-produced energy is 3 to 7 times cheaper than intrastate natural gas. Production has risen from 18,000 short tons in 1950 to 14 million tons in 1976 and will exceed 50 million tons by 1985.

Lignite occurs in three Eocene stratigraphic units--the Wilcox Group, Yegua Formation, and Jackson Group--and in three ancient depositional systems-fluvial, deltaic, and strandplain/lagoonal.

Contributing about 25 percent of all the energy ever produced in the United States, Texas has for 50 years led the nation in energy production.

Five distinct facies are recognized in the Eocene Queen City exposures between the Trinity River valley and the Louisiana state boundary. These facies (fluvial, deltaic, tidal flat, barrier, and tidal delta) display diagnostic suites of physical and biogenic structures.

The suitability of salt domes in the east Texas basin (Tyler basin), Texas, for long-term isolation of nuclear wastes is being evaluated. The major issues concern hydrogeologic and tectonic stability of the domes and potential natural resources in the basin.