Interpretation of existing geothermometry data combined with new vitrinite reflectance data, within the framework of a detailed composite tectonic setting, elucidates the evolution of structural sequencing of thrust sheets during the Alleghanian event in the Valley and Ridge Province in Virginia. That the Pulaski thrust sheet preceded the Saltville thrust sheet in the emplacement sequence, and that both reached thermal maxima prior to, or during, respective emplacement may be inferred from vitrinite and other geothermometry data. In contrast, the Narrows and St. Clair thrust sheets probably each attained their thermal maximum after emplacement. New vitrinite reflectance data are consistent with CAI and other temperature-sensitive information heretofore ascertained in the Valley and Ridge Province and support previously established maximum temperatures of ca. 200°C for strata of the Saltville thrust sheet as young as Mississippian. Rmax values from Mississippian coals in the Price Formation of the Saltville sheet, beneath but near the Pulaski thrust, range from 1.61% to 2.60%. At the structural front of the fold and thrust belt, a single Mississippian coal sample from the Bluefield Formation yields an Rmax value of 1.35%. Those coals showing highest Rmax values are more intensely fractured with secondary minerals filling the fractures. Warm fluids introduced during tectonic events may have played at least as important a role as that of combined stratigraphic and tectonic burial.
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The balanced cross section in figure 4 is generalized from the geologic map of the Radford 1:100,000 quadrangle (in preparation for the U.S. Geol. Survey misc. map series) by M. J. Bartholomew, A. P. Schultz, S. E. Lewis, and R. C. McDowell.
Lewis, Sharon E. and Hower, James C., "Implications of Thermal Events on Thrust Emplacement Sequence in the Appalachian Fold and Thrust Belt: Some New Vitrinite Reflectance Data" (1990). Center for Applied Energy Research Faculty and Staff Publications. 11.