The Oakville Sandstone is a major aquifer and a major host of uranium deposits in the Texas Coastal Plain. This report discusses the geochemistry - including major ions, the trace elements uranium, molybdenum, arsenic, and selenium, and oxidation-reduction potential - of Oakville ground water to evaluate the potential effect of uranium mining on water quality. Ground-water chemistry was investigated both regionally and in two major uranium mining districts.

The Wink Sink in Winkler County, Texas, formed on June 3, 1980. Within 24 hours it had expanded to a maximum width of 360 ft (110 m). On June 5, 1980, maximum depth of the sinkhole was 110 ft (34 m), and volume about 5.6 million ft3 (158,600 m3). Between June 3 and June 6, 1980, a large area bordering the south rim of the sink subsided about 10 ft (3 m) relative to the north side. Further subsidence of 1,456 ft (44.4 cm) occurred along the southern rim between July 19 and December 12, 1980.

The Frio Formation is one of the major Tertiary progradational wedges of the Texas Gulf Coast Basin and has yielded nearly 6 billion bbl of oil and 60trillion ft30f gas. The Frio and its updip equivalent, the Catahoula Formation, consist of deposits of two large fluvial and associated deltaic systems centered in the Houston and Rio Grande Embayments. Structures in the Houston Embayment are dominated by syndepositional deformation of underlying Jurassic salt.