华南古、中生代之交牙形石原位氧同位素分析及其古气候重建

项目名称： 华南古、中生代之交牙形石原位氧同位素分析及其古气候重建

项目编号： No.41272025

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 天文学、地球科学

项目作者： 赵来时

作者单位： 中国地质大学（武汉）

项目金额： 102万元

中文摘要： 本项目拟对华南几个研究程度较高并富含牙形石化石的二叠-三叠系界线地质剖面如安徽巢湖平顶山、贵州关刀、广西作登、湖北大峡口及浙江煤山等剖面进行系统地采集牙形石化石样品，并充分利用已获得的牙形石标本,依托Cameca IMS-1280离子探针技术和实验方法对牙形石微区原位氧同位素组成进行系统测量并开展高分辨率牙形石原位氧同位素分析研究。该研究有望首次建立不同相区古、中生代之交及早三叠世牙形石原位氧同位素组成变化模式与古海洋化学、古气候变化以及主要生物事件之间的对应关系；通过氧同位素恢复晚二叠世至整个早三叠世的古温度变化趋势、时限和幅度，从而揭示古生代末生物大灭绝事件及其之后生物的滞后复苏与古温度和古海洋化学变化的内在联系，为查明引起二叠纪末生物大灭绝的元凶提供新的研究思路，加强了我国在世界范围内在二叠纪-三叠纪之交群集大灭绝事件这一热点研究中的领先地位。

中文关键词： 高分辨率；牙形石；原位氧同位素；重大突变期；SIMS

英文摘要： The proposed study aims to re-sample systematically several raltively better studied,conodont-enriched Permian-Triassic boundary sections in South China such as Meishan of Zhejiang, Guandao of Guizhou, Zuodeng of Guangxi, Xiakou of Hubei, and Chaohu of Anhui. The newly obtained conodonts as well as these previously obtained specimens will be ultilized to undertake oxygen isotopic analysis of apatites. Unlike the previous approaches, this study attempts to conduct the high-resolution, in situ analysis of conodont oxygen isotopes at mm-scale using the Cameca IMS-1280 techniques and methodology. Paleoclimatic change over the Paleozoic-Mesozoic transition is anticipated to be revealed on the basis of paleotemperature changes derived from oxygen isotope excursions of conodont apatites. This study therefore is able to determine the relationships between temporature change and biotic crisis during this critical period. In addition, the selected sections represent sedimentation in various environmental settings. Thus, various oxygenic isotopes and oceanic geochemical conditions derived from conodont apatites of different environmental settings are greatly helpful in exploitting the possible causes triggerring the biotic mass extinction and delayed recovery during the Paleozoic-Mesozoic transition. The proposed project

英文关键词： High resolution；Conodonts；In-situ Oxygen isotope；great turning perriods；SIMS