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Plume Tectonics and Earth's greatest biocrisis

地幔柱构造和地球最大的生物危机

基本信息

批准号：
12573011
负责人：
ISOZAKI Yukio
金额：
$ 9.98万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2003
项目状态：
已结题

项目摘要

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.

为了弄清这次地球上最大规模的跨古生代-中生代生物大灭绝事件的成因，在4年时间里，在华南地区（四川、陕西、云南、广西、紫河尖）暴露较好的剖面上进行了6次沿着的野外研究。除项目负责人外，中国同行（姚教授）和来自日本和中国的5名研究生也参加了该项目。重点研究的是四川的朝天和峨眉山剖面以及陕西的吴家坪剖面。野外详细描述、岩样采集与钻探相结合。岩石样品在实验室进行了XRF，质谱仪，穆斯堡尔光谱等额外的现场研究和室内分析在九州和本州（日本）的等效岩石进行比较。分析集中在双阶段的大规模灭绝，即，都跨越了G-L边界和P-T边界，研究结果表明：1.在双期块状构造的G-L和P-T界线上，酸性凝灰岩层广泛发育; 2.在日本洋中古环礁灰岩中，酸性凝灰岩层进一步伸展; 3.双期块状构造和P-T界线之间的同步性。阶段性生物大灭绝和酸性火山作用的研究成果，部分成果已发表在17篇科学论文和5本专著中。其余结果的公布正在按适当的时间表进行。