Plume Tectonics and Earth's greatest biocrisis

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Field research was conducted along well-exposed sections in South China (Sichuan, Shaanxi, Yunnan, Guanxi, Zihejian) for 6 times in 4 years, in order to clarify the cause of the Earth's greatest mass extinction across the Paleozoic-Mesozoic boundary. In addition to the leader of the project, a Chinese counterpart (Prof. Yao) and 5 graduate students from Japan and China participated.Intensely studied were the Chaotian and Emeishan sections in Sichuan plus the Wujiapin section in Shaanxi. Detailed description in the field and collection of rock samples were combined with drilling. Rock samples were processed in the laboratory for XRF, Mass spectrometer, Moessbauer spectroscopy etc. Additional field study and indoor analysis were done for the equivalent rocks in Kyushu and Honshu (Japan) for comparison. Analysis focused on the double-phased mass extinction, i.e., both across the G-L, boundary and P-T boundary, and the following results were obtained.1.Extensive development of acidic tuff beds across the G-L and P-T boundaries of double-phased mass extinction.2.Further extension of these tuff beds in mid-oceanic paleo-atoll limestone in Japan.3.Synchronicity between double-phased mass extinction and acidic volcanism in a global scale.Above results were partly summarized into 17 scientific articles and 5 books. Publication of the rest results is going on in a proper schedule.