PROVENANCE EVOLUTION DURING ASSEMBLY OF THE ACADIAN/NEOACADIAN OROGEN: DETRITAL ZIRCON DATA FROM THE DEVONIAN OF NEW YORK
Upper Middle Devonian (Givetian) clastics are dominated by Grenville zircons, but include larger ca. 470-420 Ma populations from igneous and metamorphic sources within the Appalachian Orogen. Lower Upper Devonian (Frasnian) strata contain zircon suites signaling new source terranes including Neoproterozoic ‘peri-Gondwana’ (ca. 950-540 Ma) source rocks. Zircon populations from the lower Frasnian Oneonta Formation document an abrupt shift to a provenance with much greater abundance of Neoproterozoic age materials, related to the unroofing of previously unexposed source rocks. Nd-Sm data from basinward equivalents of the Oneonta also indicate the input of more juvenile clastic material. The younger Frasnian strata (Walton and Slide Mountain Formations) contain relatively fewer Neoproterozoic zircons, and increased contributions from Paleozoic igneous and metamorphic sources.