Paleomagnetic Constraints on the Permian-Triassic Boundary in Terrestrial Strata of the Karoo Supergroup, South Africa: Implications for Causes of the End-Permian Extinction Event |
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Authors: | MO De Kock JL Kirschvink |
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Institution: | aDepartment of Geology, Rand Afrikaans University, P.O. Box 524, Aucklandpark 2006, South Africa;bCalifornia Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA |
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Abstract: | The closure of the Palaeozoic witnessed the greatest biotic crisis in earth history. Surprisingly little is known about the effects and timing of the terrestrial counterpart of the well-described End-Permian mass extinction from known marine successions worldwide. In the present study, reliable paleomagnetic results were obtained from a PT boundary section in the terrestrial Karoo Basin of South Africa. Permo-Triassic aged mudstones from a locality in the Eastern Cape Province yielded two magnetic chrons, reverse followed by normal (with the boundary possibly close to the reversal). This extends to results from a previous study: thereby jointly identifying a R/N/R polarity pattern for this boundary interval. The PTB interval is constrained below the red mudstones of the Beaufort Group at the present locality and within reverse-magnetised green mudstone, implying a diachronic relation between the marine and terrestrial End-Permian mass extinction events. |
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Keywords: | Permian-Triassic boundary extinction paleomagnetism Karoo Supergroup South Africa |
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