Variable intensity of diagenesis is the factor primarily responsible for contrasting regional reservoir quality of Tertiary sandstones from the upper and lower Texas coast. Detailed comparison of Frio sandstone from the Chocolate Bayou/Danbury Dome area, Brazoria County, and Vicksburg sandstones from the McAllen Ranch Field area, Hidalgo County, reveals that extent of diagenetic modification is most strongly influenced by (1) detrital mineralogy and (2) regional geothermal gradients.

The Bureau of Economic Geology—this bureaucratic title belies the essence of this organization: an ongoing group of professionals with a definite personality. In fact, the history of public geological research in Texas is the story of dedicated, inquisitive scientists shunning the higher salaries and opportunities offered by private enterprise to serve their science and the State of Texas.

Upper Miocene, Pliocene, and Pleistocene deposits in the subsurface of the central Coastal Plain of Texas were subdivided into six operational units comprising the surface-defined Fleming, Goliad, Willis, Lissie, and Beaumont Formations. These sedimentary units constitute the last major depositional episodes in the northwestern Gulf Coast Basin. Late Miocene deposition is represented by transgressive shelf and shallow-marine shales overlain by progradational clastics of the upper part of the Lower Fleming, Upper Fleming, and Lower Goliad-Willis units.

Lineament analysis is part of a broad spectrum of structural studies employed to determine the tectonic stability of the East Texas Basin. Such information is necessary to assess the suitability of East Texas salt domes as possible repository sites for the storage of high-level nuclear wastes.