33 Ductile to Brittle Deformation in the Southern Appalachians: Grenville to Present

Tuesday, 16 April 2024
8:00 AM - 10:00 AM
Windsor Ballroom Salon A

AN ASSESSMENT OF THE TECTONIC HISTORY OF THE SOUTHERN APPALACHIANS BY INTEGRATING U-PB GEOCHRONOLOGY AND ELEMENTAL RATIOS OF ZIRCONS FROM THE BLUE RIDGE, PIEDMONT, AND COASTAL PLAIN

Paper number: 33-4
Program: Theme Sessions
Time: 9:00 AM – 9:20 AM

Authors

Abstract

Despite serving as a prototypical example of continental collision and supercontinent formation, a comprehensive chronology of deformation, metamorphism and magmatism in the Appalachian mountains remains elusive. Whereas Appalachian orogenesis has often been viewed as the result of a series of discrete tectonic episodes, the growing database of Appalachian tectonics may support more continuous and/or diachronous models. Here we use variations in U-Pb ages and elemental ratios from southern Appalachian zircons collected from in situ crystalline rocks and the detritus eroded from them to better constrain the integrated history of southern Appalachian tectonics. U/Th data coupled with U-Pb ages from zircons in and derived from the southern Appalachians indicate substantial Devonian metamorphism and minimal Carboniferous-Permian and Ordovician metamorphism. These data support less episodic tectonic models, and suggest peak metamorphism occurred during the Acadian phase of the orogeny. U-Pb detrital-zircon ages from Mesozoic-Cenozoic sediments and sedimentary rocks derived from the southern Appalachians indicate dominant periods of magmatism during the Silurian and Carboniferous periods.

Geological Society of America Abstracts with Programs. Vol. 56, No. 2

doi: 10.1130/abs/2024SE-398424

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