Abstract: Field Studies of Parsons and Petersburg Structural Lineaments, West Virginia
Russell L. Wheeler, Roy S. Sites
The Parsons and Petersburg structural lineaments are major, cross-strike zones of structural discontinuities in the Appalachians' eastern Plateau and western Valley and Ridge provinces. Subtle expressions of both lineaments appear to cross the Allegheny Front. Both lineaments resemble and differ from other such structures elsewhere in the Appalachians and in other petroliferous and metalliferous forelands. Aside from possible effects on standard structural and stratigraphic traps, both lineaments expose and affect Silurian and Devonian gas-producing intervals of West Virginia.
The Parsons lineament is a northwest-trending zone at least 55 km long, 10 km wide, and 3 km deep. The Petersburg lineament trends east-northeast and is at least 80 × 8 × 5 km. Major folds, longitudinal reverse faults, intermediate-scale folds, and minor folds with associated northwest-vergent shear zones terminate or change abundance, size, shape, or orientation across or within the lineaments. Terminations of unmodeled gravity anomalies at the lineaments suggest that the lineaments formed over "step-ups" of basal detachments along strike. Both lineaments appear clearly on LANDSAT images. Neither seems to involve significant transverse faults. Preliminary results suggest slightly larger joints within than outside the Parsons lineament. Structural disruption increases inside both lineaments. The Parsons and Petersburg lineaments expose different structural levels of structures of similar origin, which may be present under Pennsylvanian rocks on the west, where fractured Devonian shales produce gas.
AAPG Search and Discovery Article #90968©1977 AAPG-SEPM Annual Convention and Exhibition, Washington, DC