The timing and extent of the eruption of the Siberian Traps large igneous province: Implications for the end-Permian environmental crisis |
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| Authors: | Marc K Reichow MS Pringle AI Al'Mukhamedov MB Allen VL Andreichev MM Buslov CE Davies GS Fedoseev JG Fitton S Inger AYa Medvedev C Mitchell VN Puchkov IYu Safonova RA Scott AD Saunders |
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| Institution: | 1. State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China;2. Graduate University of Chinese Academy of Sciences, Beijing 100049, China;3. Berkeley Geochronology Center, Berkeley, CA 94709, USA;1. State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China;2. University of Chinese Academy of Sciences, Beijing 100049, China;3. Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, School of Earth and Space Sciences, Peking University, Beijing 100871, China;4. Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, CA 94709, USA;5. State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Institute of Sedimentary Geology, Chengdu University of Technology, Chengdu 610059, China;2. Department of Earth and Environmental Sciences, University of St. Andrews, St. Andrews KY16 9AL, UK;3. Centre for Exploration Targeting, School of Earth and Environment, University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia;4. State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China;5. College of Earth Science, Chengdu University of Technology, Chengdu 610059, China;1. Institute of the Earth''s Crust, Siberian Branch of the Russian Academy of Sciences, 128 Lermontov Street, 664033 Irkutsk, Russia;2. University of Tasmania, School Earth Sciences, Hobart, Tasmania 7001, Australia;3. University of Oslo, Department of Geosciences, Postboks 1047, Blindern 0316, Oslo, Norway |
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| Abstract: | We present new high-precision 40Ar/39Ar ages on feldspar and biotite separates to establish the age, duration and extent of the larger Siberian Traps volcanic province. Samples include basalts and gabbros from Noril'sk, the Lower Tunguska area on the Siberian craton, the Taimyr Peninsula, the Kuznetsk Basin, Vorkuta in the Polar Urals, and from Chelyabinsk in the southern Urals. Most of the ages, except for those from Chelyabinsk, are indistinguishable from those found at Noril'sk. Cessation of activity at Noril'sk is constrained by a 40Ar/39Ar age of 250.3 ± 1.1 Ma for the uppermost Kumginsky Suite.The new 40Ar/39Ar data confirm that the bulk of Siberian volcanism occurred at 250 Ma during a period of less than 2 Ma, extending over an area of up to 5 million km2. The resolution of the data allows us to confidently conclude that the main stage of volcanism either immediately predates, or is synchronous with, the end-Permian mass extinction, further strengthening an association between volcanism and the end-Permian crisis. A sanidine age of 249.25 ± 0.14 Ma from Bed 28 tuff at the global section and stratotype at Meishan, China, allows us to bracket the P–Tr boundary to 0.58 ± 0.21 myr, and enables a direct comparison between the 40Ar/39Ar age of the Traps and the Permo–Triassic boundary section.Younger ages (243 Ma) obtained for basalts from Chelyabinsk indicate that volcanism in at least the southern part of the province continued into the Triassic. |
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