Abstract

The timing of the late Paleozoic glaciation and its terminal deglaciation in the Paraná Basin, Brazil, is unconstrained and prohibits correlation of the Paraná Basin ice record with other high-latitude Gondwanan and low-latitude contemporaneous records. Here, we reexamine the existing U-Pb framework for the Carboniferous–Permian Paraná succession through high-precision, single-crystal chemical abrasion–thermal ionization mass spectrometry (CA-TIMS) analysis of individual zircons from tonsteins and subaerial volcanic ash deposits, which overlie sedimentary deposits with glacial indicators. The new ages document two distinct volcanic intervals and define a substantially new and revised chronostratigraphy for postglacial coal-bearing intervals in the southern Paraná Basin. The new CA-TIMS ages further indicate that glaciation in south-central Gondwana, long considered to be Early Permian, is entirely Carboniferous in age and that terminal deglaciation in this key west-central Gondwanan basin occurred near the Permian-Carboniferous boundary. Single-crystal U-Pb CA-TIMS ages from the ice-proximal high-latitude basins of southern Africa and Australia are needed to test the synchronicity of late Paleozoic glaciation and deglaciation events throughout Gondwana, with implications for empirical- and model-based paleoclimate reconstructions.

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