Browsing by Author "Schultz, Arthur P."

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    Broken-formations of the Pulaski thrust sheet near Pulaski, Virginia
    Schultz, Arthur P. (Virginia Polytechnic Institute and State University, 1983)
    Broken-formations (Hsu, 1974; Harris and Milici, 1977) occur in the lower part of the Pulaski thrust sheet and contain some of the most strongly deformed sedimentary rocks in the Valley and Ridge province of the southern Appalachians. Deformation in this zone ranges from grain-scale cataclasis to regional-scale faulting. The broken-formations are distinguished from rocks structurally higher on the sheet and from rocks of the underlying Saltville sheet by (1) a sharp increase in the variability of fold and fault styles, (2) greater ranges in fold plunges and dips of axial surfaces, (3) a low degree of preferred orientation of folds and faults, (4) an increase in the frequency of mesoscopic structures, and (5) the presence of Max Meadows tectonic breccia. Structural analyses indicate that deformation in the broken-formations is Alleghanian in age and that the deformed zone formed under elastico-frictional conditions, possibly under elevated fluid pressures with temporally variant stresses and that lithology may have played an important role in localizing the broken-formations along the base of the Pulaski sheet.
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    Deformation associated with Pulaski overthrusting in the Price Mountain and East Radford windows, Montgomery County, southwest Virginia
    Schultz, Arthur P. (Virginia Polytechnic Institute and State University, 1979)
    Within the overthrust belt of southwest Virginia, windows in the Pulaski thrust sheet expose a variety of parautochthonous and allochthonous rocks, ranging in age from Cambrian to Mississippian. The décollement of the Pulaski fault as exposed in the Price Mountain and East Radford windows is in places a thick, highly complex, deformation zone. In this zone, a suite of carbonate breccias, cataclastic quartzitic rocks and deformed shales occur. The rocks of the décollement comprise a thrust chaos and tectonic mélange. Mélange and chaos fabrics are typified by folding, faulting and cataclasis. The East Radford window exposes a complexly folded and faulted antiform consisting of a telescoped, inverted stratigraphic section of Ordovician, Silurian and Devonian rocks. The antiformal structure is entirely allochthonous with minimum horizontal displacement of several kilometers. Deformation of the parautochthonous Mississippian rocks below the Pulaski décollement in the Price Mountain window includes thrust and normal faults, folds of at least 3 orders and cataclasis.