DEPOSITIONAL ENVIRONMENTS OF THE PENNSYLVANIAN POTTSVILLE FORMATION IN THE WEST BLOCTON EAST QUADRANGLE, ALABAMA

The Pennsylvania Pottsville Formation is well exposed in many areas in the West Blocton East, 1:24,000 scale Quadrangle in Alabama. The quadrangle is located along the I-20/59 development corridor and is at the southern extent of the Appalachian Valley and Ridge province. It contains Cambrian to Pennsylvanian strata in the Jones Valley and Montevallo thrust sheets.

We mapped the Pennsylvania Pottsville Formation in the quadrangle in detail and examined thin section samples to describe its lithology. In analyzing the minerals contained in the samples, the percentage of clays, replacement textures, rounding, etc. we were able to determine the depositional environment of the Pottsville Formation in the quadrangle. We took multiple pictures of each thin section and used these to highlight accessory minerals and clay content in the samples. These pictures also highlighted any fossils and other inclusions found in the samples. The main minerals found in the samples were micas, including chlorite and muscovite, clays, especially limonite, and quartz. Some samples had glauconite and actinolite, some had lithic fragments, and some had fossils. The presence of glauconite and fossils indicated that the main depositional environment of the Pottsville Formation in the West Blocton East quadrangle area was a marine continental shelf.