Academic and Scholarly Events

  • 11/15 Earth Sciences Seminar Series: Yasar Dogancan

    Department of Earth Sciences

    Fall 2024 Seminar Series

    McHugh 302

    Friday November 15, 2024

    12:30PM

    Yasar Dogancan - University of Florida

    Paleozoic Polymetamorphism of the Western Blue Ridge

    The tectonic configuration and evolu­tion of southern Appalachian orogenic epi­sodes are constrained, to a large extent, by knowledge of the timing and environment of pre- or syn-orogenic sediment deposi­tion along with their subsequent thermal and deformational histories. The orogenic events that gave rise to regional folding and Barrovian metamorphism of the Western Blue Ridge (WBR) terrane are a classic ex­ample. We present new U-Pb and 40Ar-39Ar results bearing on the timing of magma­tism and subsequent metamorphism of the Marble Hill Hornblende Schist (MHHS) of the WBR (southeastern USA). The schist is a key marker unit in the Murphy synclino­rium, a central structure in the tectonic con­figuration of the WBR. The MMHS origi­nated as basaltic volcanics overlying the Murphy Marble at the base of the Mineral Bluff Group. Ocean island basalt geochem­istry and a zircon U-Pb age of ca. 437 Ma for the MHHS is consistent with plume-related volcanism in a Silurian remnant ocean basin of the Iapetus Ocean. Hornblende 40Ar-39Ar and rutile U-Pb ages for the MHHS are ca. 380–340 Ma and ca. 320 Ma, respectively, and record subsequent amphibolite facies metamorphism during Devonian Acadian orogeny and the deformation through re­gional folding and thrusting during the Carboniferous Alleghanian orogeny. The new age constraints for the MHHS require that “isograds” mapped in the region of the Murphy Belt are actually polymetamor­phic mineral distributions that developed at least in part through post-Silurian tectonic events.

    For more information, contact: Christin Donnelly at christin.donnelly@uconn.edu