Outcrop Expression of Late Devonian Transgressive-Regressive Cycles along Catskill Delta Complex Basin Margin of Central West Virginia: ABSTRACT

Abstract

The Upper Devonian Catskill delta complex prograded westward across the central Appalachian basin in response to eustatic fluctuations in sea level and high rates of sediment supply associated with the Acadian orogeny. Excellent outcrops of Catskill delta complex basin-margin facies, located near Elkins, West Virginia, record a hierarchy of transgressive-regressive (T-R) cycles that formed as the Catskill shoreline regressed across east-central West Virginia during the middle Famennian. Subsurface mapping of intervals studied in outcrop indicates three distinct scales of T-R cycles based on the magnitude and lateral continuity of shoreline shift and the thickness of enclosed strata. Major cycles represent regional shifts of 30-50 mi (48-80 km), and are roughly 350 ft (100 m) thick. Intermediate cycles indicate more localized shoreline shifts of 15-25 mi (25-40 km), and are approximately 100-150 ft (30-50 m) thick. Minor cycles are expressed as local and minor shifts of less than 5 mi (8 km), and are from 10 to 30 ft (3-10 m) thick.