Reconstructing the Acadian Orogeny using U–Pb–He Double Dating of Detrital Zircon: Provenance and Thermal History of the Catskill–Pocono Wedge

The Paleozoic Appalachian orogen extends >3000 km from Newfoundland through Alabama and is composed of a mosaic of terranes representing multiple collisional orogenic phases during the progressive closure of the Iapetus Ocean, culminating in the assembly of Pangea. The Devonian–Mississippian Acadian orogenic phase is characterized by the accretion of the Avalonia and Carolina terranes, growth of an orogenic plateau, a global decrease in temperature, and a series of marine mass extinctions. Reconstructing Acadian orogenic evolution, exhumation, and sediment dispersal is key to understanding the Paleozoic tectonic, climatic, and biologic evolution of eastern Laurentia. The sedimentary record of these processes is archived in the ~18-km-thick Appalachian foreland, including the >3-km-thick Devonian–Mississippian Catskill-Pocono siliciclastic wedge. Here, we present new double-dated detrital zircon (U–Th)/(He–Pb) data from the Catskill–Pocono wedge. New provenance and sediment inverse thermal history modeling characterize exhumation and fluvial routing from potential orogenic source areas, along with the foreland basin response to Acadian and broader Appalachian tectonics. Detrital zircon U–Pb ages are dominated by Taconic (420–490 Ma) and Grenville (900–1300 Ma) ages and include minor Pan-African (510–680 Ma) and Laurentian craton (1600–1900 Ma) ages, whereas (U–Th)/He dates range from 249 to 440 Ma. The new results are synthesized into a holistic provenance reconstruction across the Acadian foreland basin. These results are not only important for understanding Acadian hinterland evolution and sediment dispersal, but bear on provenance interpretations and potential for sediment recycling during post-Acadian tectonics and sediment routing reconstructions across Laurentia.