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The AAPG/Datapages Combined Publications Database
Cross-strike structural discontinuities (CSDs) are zones of structural disruption several kilometers wide in the Appalachian and other overthrust belts. CSDs are not faults or fault zones. They typically contain about 1,000 cu km of unusually fractured rock. For example, in eastern West Virginia, one CSD (Parsons lineament) trends west-northwest at least from the Appalachian front to the Intraplateau structural front, with no evidence of basement involvement. The Parsons lineament has double to triple the normal joint intensity in exposed Upper Devonian siltstones. Another CSD (Petersburg lineament) trends west-southwest from the western Valley and Ridge province, and crosses the Appalachian structural front. The Petersburg lineament aligns with Arkle's hinge line, a prob ble basement flexure under the western and central Plateau province, and has twice-normal joint intensity in exposed Lower Pennsylvanian sandstones. The two CSDs appear to intersect in southern Tucker and northern Randolph Counties, West Virginia.
CSDs and their intersections, particularly beneath intersections of short air-photo lineaments, may comprise highly permeable fractured reservoirs. If the seal is preserved, CSDs can provide a tool for extending exploration into the little-tested eastern Plateau province of West Virginia and adjacent states, where organic-rich Devonian shales are thick and thermally mature.
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