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Browsing by Author "Broughton, P. L."

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    Structural geology of the Pulaski-Salem thrust sheet and the eastern end of the Christiansburg window, southwestern Virginia
    Broughton, P. L. (Virginia Polytechnic Institute and State University, 1971)
    The map area comprises about 35 square miles in Montgomery County, Virginia. The bedrock ranges in age from Cambrian to Devonian and belongs to five fault blocks. From north to south they are Catawba, Salem, Pulaski, Saltville and Max Meadows. The structurally lowest block is the parautochthonous Saltville block which is exposed in the Christiansburg window of the Pulaski overthrust sheet. Exposed are the upper Elbrook Formation, the Cambro-Ordovician Knox Group of carbonates and Middle Ordovician limestones. The strata within the window represent the essentially recumbent north limb of the Christiansburg anticlinorium. The Pulaski-Salem blocks contain folded and highly-fractured and brecciated Elbrook and Knox formations. Structural complications of the Salem block include the high-angle Willow Springs, Cambria, North Cambria and Kettle Ridge faults. The Salem thrust is interpreted as a relatively minor, yet important, display off the Mississippian-age Pulaski thrust. The Pulaski overthrust has a minimum of 9 miles of northwestward displacement. Rocks of the Catawba block along the northern margin of the area range from Middle Cambrian to Mississippian in age. The Max Meadows block is the highest structural block in the area. Cambrian Rome Formation and possibly some lower Knox Copper Ridge Formation comprise this thrust sheet. Klippen of the Max Meadows thrust indicate a minimum northwestward movement of 15,000 feet for this thrust sheet.