Sequence stratigraphy of Upper Mississippian strata in the central Appalachians: A record of glacioeustasy and tectonoeustasy in a foreland basin setting

The Upper Mississippian Hinton, Princeton, and Bluestone formations of sout hern West Virginia constitute a westward-thinning wedge of strata that fill ed the central Appalachian basin over approximately 7 m.y. Up to 17 transgr essive-regressive sequences comprise the study interval in the basin depoce nter. High-frequency fourth-order (similar to 400 k.y.) sequences vary with regard to the degree of basal incision, the overall thickness, and the cha racter of the dominant facies. Five sequence types are recognized in the ou tcrop brit: (1) major incised valley fill to coastal plain. (2) major incis ed valley fill to deltaic, (3) minor incised valley fill, (4) coastal plain , and (5) marine-dominated sequences. Sequence development is ascribed to g lacioeustasy during the early stages of the Permian-Carboniferous Gondwanan glaciation. Regional well log correlation indicates that the high-frequency sequences s tack into two composite sequences. These composite sequences consist of (1) a major incised valley-fill-dominated sequence and a set of coastal plain- dominated sequences that together constitute the transgressive systems trac t, (2) a marine-dominated sequence that demarcates maximum flooding, and (3 ) (where preserved) a progradational set of minor incised valley-fill-domin ated sequences that comprise die highstand systems tract. The composite seq uences are interpreted to reflect third-order (2-4 m.y.) changes in accommo dation as a result of tectonically driven eustasy.