Study on the cause of the Earth's greatest mass extinction

地球最大规模灭绝原因研究

基本信息

批准号：
10041113
负责人：
ISOZAKI Yukio
金额：
$ 6.02万
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 (A).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

This project was aimed to reveal the cause of the Permo-Triassic boundary (ca. 250 million years ago) mass extinction which represents the greatest biospheric catastrophe in the Earth's history. We planned to collect a continuous sedimentary sequence that recorded the secular environmental change around the P-T boundary, particularly by deep-drilling, because it is critical for this study to obtain weathering -free fresh rock samples for geochemnical analyses. Out of 4 candidate sections in South China, the Chaotien section was chosen on the basis of preliminary field research in winter of 1998. We conducted an academic drilling at Chaotien in northern Sicuan province in summer of 1999 and recovered 260 m long drilled core samples. The section along the Jialingian river covers the entire Upper Permian series from top Maokoan to Changhsingian plus the lowest Griesbachian of Lower Triassic. Numerous samples including ammonoid, coral, brachiopod and fusulinid fossils collected from surfac … More e outcrops made the total sample weight ca. 5 tons.These samples were shipped to Tokyo in Fall of 1999 and are currently under geochemical analyses in various aspects including major element composition, carbon isotope ratio plus rare earth element composition. In Particular, the Scanning X-ray Analyzing Microscope of the Nagoya Univ. is used for recovering visualized images of chemical composition of the samples. As the geochemical analysis has just started, results will be summarized later on.According to the field research and preliminary indoor analyses, the following new observations were made ; 1) The Chaotien section covers fossiliferous Upper Maokoan, Wuchapingian and Canhsingian plus the lowest Griesbachian on the basis of index fossils, 2) the cored samples are quite fresh, much better than those from the outcrop, 3) This section has many tuff layers whose horizons often correspond to the disappearance horizon of particular fossils. This suggests the "Plume Winter" scenario (proposed by the project leader) that connects plume-induced extraodinarily violent volcanism with the Pangean supercontinent breakup, and with the global environmental change associated with mass extinction across the P-T boundary. Less

该项目的目的是揭示渗透性边界的原因（2.5亿年前）质量扩展，这代表了地球历史上最大的生物圈灾难。我们计划收集一个连续的沉积序列，该序列记录了P-T边界周围的安全环境变化，尤其是通过深度钻探，因为这项研究至关重要的是获得无风化的新鲜岩石样品进行地球分析。在中国南部的4个候选部门中，Chaotien部分是根据1998年冬天的初步现场研究选择的。我们于1999年夏天在北西库安省的Chaotien进行了一次学术钻探，并收回了260 m的长期钻探核心样品。沿着贾林格河（Jialingian River）的截面涵盖了从顶级毛雄（Top Mayokoan）到昌辛格（Changhsingian）的整个上层二叠纪系列，以及下三叠纪最低的格里斯巴赫（Griesbachian）。从Surfac收集的许多样品，包括氨基，珊瑚，腕足类和熔融化石……更多的E露头使总样品重量CA。 5吨。这些样品于1999年秋季运往东京，目前正在各个方面的地球化学分析中，包括主要元素组成，碳同位素比以及稀土元素组成。特别是，扫描X射线分析了名古屋大学的显微镜。用于恢复样品化学成分的可视化图像。由于地球化学分析刚刚开始，结果将在稍后进行总结。根据现场研究和初步的室内分析，进行了以下新的观察结果。 1）Chaotien部分涵盖了化石上部的Mookoan，Wuchapingian和Canhsingian，加上最低的Griesbachian，在索引化石的基础上，2）芯片样品非常新鲜，比露头的好东西要好得多，比露头中的样本要好得多，3）这一部分经常对相对的tuff层与特定的水平相对应的tuff层相对应。这表明“羽毛状冬季”场景（由项目负责人提出），该场景将羽流引起的暴力火山和庞吉超大陆分解连接起来，并随着全球环境变化与P-T边界的质量扩展有关。较少的