Advances in numerical calibration of the Permian timescale based on radioisotopic geochronology
Radioisotopic age determinations targeted at key stratigraphic successions worldwide continue to refine the geological timescale with increasing precision and accuracy and to unravel the tempo of global geological, palaeoclimatic and palaeobiotic processes that have shaped our planet. The last decade has witnessed significant progress in the calibration of the Permian Period through integrated stratigraphic, palaeontological and high-precision geochronological investigations. These studies have largely focused on the Cisuralian and Lopingian stages, particularly the end-Permian mass extinction, whereas much of the Guadalupian and its associated events remain inadequately calibrated. A compilation of the high-precision U–Pb geochronology generated in the past ten years yields ages of 298.92±0.19 Ma for the onset of the Permian, 293.52±0.17 Ma for the base-Sakmarian, 290.10±0.14 Ma for the base-Artinskian, 272.95±0.11 Ma for the Cisuralian–Guadalupian boundary, 265.22±0.34 Ma for the base-Capitanian, 254.14±0.12 Ma for the base-Changhsingian and 251.90±0.10 Ma for the Permian–Triassic boundary. Extension of modern astrochronological methods to the Palaeozoic Era presents new opportunities for broader stratigraphic correlations and enhanced calibration of the Permian timescale.
Supplementary material: Table S1 (U–Pb data) is available at https://doi.org/10.6084/m9.figshare.c.3917425
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The Palaeozoic Era ends with the c. 47-million-year-long Permian Period. This was a major juncture in Earth history when the vast Pangean supercontinent continued its assembly and the global biota suffered the most extensive biotic decimation of the Phanerozoic, the end-Permian mass extinction. It was also the time of accumulation of vast mineral and energy deposits, notably of salt and petroleum. The temporal ordering of geological and biotic events during Permian time is, therefore, critical to the interpretation of some unique and pivotal events in Earth history. This temporal ordering is based mostly on the Permian timescale, which has been developed and refined for nearly two centuries. This book reviews the history of the development of the Permian chronostratigraphic scale. It also includes comprehensive analyses of Permian radioisotopic ages, magnetostratigraphy, isotope-based correlations, and timescale-relevant marine and non-marine biostratigraphy and biochronology.