Physical Sciences and Mathematics Commons^™

Nealian And Lenoxian (Wolfcampian, Lower Permian) Depositional Sequences, Fusulinid Facies And Biostratigraphy, Glass Mountains, Texas, Charles A. Ross, June R. P. Ross

Geology Faculty Publications

The Wolfcampian Series crops out along the base of the Glass Mountains escarpment (King, 1930, 1937) and, in the western part of the Marathon Basin, in folded and faulted beds exposed in the Dugout structural fold belt, the westernmost belt in the Marathon Orogen (Ross, 1963). The Wolfcampian is divided into two stages, a lower Nealian Stage and an upper Lenoxian Stage (Ross and Ross, 1987a, 1987b). Strata of these two stages are separated by a major tectonic event in the history of the Marathon orogeny and, as a result, by a major angular unconformity that separates the structurally deformed …

Hessian (Leonardian, Middle Lower Permian) Depositional Sequences And Their Fusulinid Zones, West Texas, Charles A. Ross, June R. P. Ross

Geology Faculty Publications

The lower Leonardian (Lower Permian) Hess Limestone in the eastern part of the Glass Mountains, West Texas, forms a high, well-exposed escarpment of repetitious, shallow-water, platform limestone facies for about 35 km. The strike of the outcrops cuts the strike of depositional facies at relatively low angle so that the actual width of the carbonate platform, from its marginal rim to shore facies, was probably less than 10 km (Figs. 1, 2). At the platform margin, the Hess Limestone passes abruptly into coarse, conglomeratic slope deposits that form the Skinner Ranch Formation. The pebbles, cobbles, boulders, (some the size of …

Late Paleozoic Sea Levels And Depositional Sequences, Charles A. Ross, June R. P. Ross

Geology Faculty Publications

Cyclic sea level charts for the Lower Carboniferous (Mississippian), Middle and Upper Carboniferous (Pennsylvanian), and Permian show considerable variability in the duration and magnitude of third-order depositional sequences, and also in the position of general sea level as represented by second-order sea level. Transgressive and highstand system tracts are numerous on the cratonic shelves of the late Paleozoic continents. Shelf margin wedges are less well represented except at times of general lower sea levels. Most low stand wedges and all low stand fan systems are structurally deformed and make up many of the accretionary wedges and displaced terranes that lie …

Biostratigraphic Zonation Of Late Paleozoic Depositional Sequences, Charles A. Ross, June R. P. Ross

Geology Faculty Publications

Correlation of more than seventy third-order depositional sequences in Carboniferous and Permian strata uses assemblage zones of warm water benthic and nektonic shelf faunas. These include calcareous foraminifers, bryozoans, conodonts, and ammonoids and represent tropical, subtropical, and warm temperate water faunas from carbonate shelves and adjacent cratonic basins.

After the Early Carboniferous faunal zonation was highly provincial and worldwide correlations of depositional sequences are based on interpretations of evolutionary lineages and depositional patterns in each province and in identifying times of limited dispersals between provinces.

Associated with these faunal zones there were times of expanded or reduced faunal diversities and …