Controls of Early Pennsylvanian Sedimentation in Western Pennsylvania
Paleotopography produced by tectonism and sedimentological processes controls sediment patterns in the Pennsylvanian of western Pennsylvania. Regional basin subsidence, reactivated basement highs, and growing folds and lineaments were the three tectonic factors which interacted to produce the relatively large-scale facies patterns. The facies patterns are especially marked in sediments where water depth was critical to their formation, that is, coals, marine and continental shales, limestones, and under-clays. Local paleotopography produced by differential sedimentation, erosion, and compaction also exerted a marked effect on sediment composition and thickness and constitutes a fourth factor controlling facies patterns. The separate and combined effect of these four orders of factors on sedimentation are analyzed by examples taken from recently completed and published works.