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http://www.sciencedirect.com/science/article/pii/S1674987112001041 |
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| Authors: | Andreas Prokoph Hafida El Bilali Richard Ernst |
| Institution: | 1. Speedstat, 19 Langstrom Crescent, Ottawa, ON K1G 5J5, Canada 2. Carleton University, Department of Earth Sciences, Herzberg Building, Ottawa, ON K1S 5B6, Canada 3. Carleton University, Department of Earth Sciences, Herzberg Building, Ottawa, ON K1S 5B6, Canada ;ErnstGeosciences, 43 Margrave Avenue, Ottawa, ON K1T 3Y2, Canada |
| Abstract: | Large igneous provinces (LIPs) are considered a relevant cause for mass extinctions of marine life throughout Earth’s history. Their flood basalts and associated intrusions can cause significant release of SO4 and CO2 and consequently, cause major environmental disruptions. Here, we reconstruct the long-term periodic pattern of LIP emplacement and its impact on ocean chemistry and biodiversity from δ34Ssulfate of the last 520 Ma under particular consideration of the preservation limits of LIP records. A combination of cross-wavelet and other time-series analysis methods has been applied to quantify a potential chain of linkage between LIP emplacement periodicity, geochemical changes and the Phanerozoic marine genera record. We suggest a mantle plume cyclicity represented by LIP volumes (V) of V = ?(350–770) × 103 km3 sin(2πt/170 Ma) + (300–650) × 103 km3 sin(2πt/64.5 Ma + 2.3) for t = time in Ma. A shift from the 64.5 Ma to a weaker ～28–35 Ma LIP cyclicity during the Jurassic contributes together with probably independent changes in the marine sulfur cycle to less ocean anoxia, and a general stabilization of ocean chemistry and increasing marine biodiversity throughout the last ～135 Ma. The LIP cycle pattern is coherent with marine biodiversity fluctuations corresponding to a reduction of marine biodiversity of ～120 genera/Ma at ～600 × 103 km3 LIP eruption volume. The 62–65 Ma LIP cycle pattern as well as excursion in δ34Ssulfate and marine genera reduction suggest a not-yet identified found LIP event at ～440–450 Ma. |
| Keywords: | Large igneous provinces Wavelet transform Sulfur isotope Mantle plume Marine biodiversity Periodicity |
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