In response to a need for a concise presentation of new terms and concepts in salt tectonics, we have compiled a glossary that focuses on ideas developed during the 1980's. Unlike conventional glossaries, ours is conceptual rather than alphabetical; each term is defined in the context of preceding terms. When known, the first paper to define or develop a new term has been cited. The purpose of this glossary is to promote a common language for salt tectonics, so that terminology and concepts will be better understood and so that the discipline will continue to develop.
Sixteen depositional sequences, commonly called cyclothems, each composed mostly of limestone(retrogradational/transgressive) and siliciclastic (progradational/regressive) subsequences, or systems tracts, record the paleogeography during Late Pennsylvanian (Virgilian Epoch) and Early Permian (Wolfcampian Epoch) Periods on the Eastern Shelf and adjacent Midland Basin, North-Central Texas.
The hydrochemical history of ground water in the arid southeastern Hueco Bolson and southwestern Diablo Plateau was investigated by collecting soil-moisture samples from unsaturated siliciclastic bolson-fill sediments and groundwater samples from the Diablo Plateau aquifer, the Hueco Bolson silt and sand aquifer, and the Rio Grande alluvial aquifer. Major, minor, and trace solutes, stable isotopic compositions, and activities of tritium and carbon-14 were measured in ground-water samples; major solute concentrations were determined in soil-moisture samples.
Geologic mapping and fracture analysis of the Lower Cretaceous Edwards aquifer strata near Georgetown and Round Rock, Texas, were performed to provide a better understanding of the geologic framework of the Balcones Fault Zone and to provide information for assessing ground-water flow characteristics. Cretaceous strata dip gently eastward and are locally overlain by terrace deposits and alluvium. Several major normal faults, downthrown to the east, strike northward across the area. Gentle flexures, possibly related to faulting, parallel the faults.