PALEONTOLOGICAL AND PETROLOGICAL STUDY OF LIMESTONES IN THE PERMIAN-TRIASSIC BOUNDARY

二叠纪-三叠纪边界石灰岩的古生物学和岩石学研究

• 批准号: 05454002
• 负责人: KOIKE Toshio
• 金额: $ 3.9万
• 依托单位: YOKOHAMA NATIONAL UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05454002/
• 关键词: PERMIAN-TRIASSIC BOUNDARY; CONODONT FOSSILS; FUSULINID FOSSILS; TEXTURE AND COMPONENTS OF LIMESTONE; 紡鍾虫化石

A drilling (50 m in depth. 70 mm in diameter) was performed in 1994 for the purpose of getting information about the Permian-Triassic boundary in the Taho Limestone exposed in Tahokamigumi. Shirokawa-cho. Higashiuwa-gun. Ehime Prefecture. As a result of investigation of the drilling core, there occures the lower Triassic Griesbachian conodont Hindeodus minutus. H.parvus. and? Isarcicella isarcica from the dark gray dolomitic limestone in the level of 22.80 m to 23.45 m and permian fusulinid Staffella sp. from the light gray dolomitic limestone at the level of 23.50 m below the grand surface. We propose the Taho Formation for the Triassic limestone and the Shirokawa Formation for the Permian Limestone. The boundary between the formations is conformable.The boundary between the Upper Permian Mitai Formation and the Triassic Kamura Formation exposed in Shioinosou. Takachiho-cho. Nishiusuki-gun. Miyazaki Prefecture. We confirmed the occurrence of Hindeodus minutus. H.parvus. Isarcicella is … More arcica. and Neogondolella carinata from the dark gray limestone with small gastropods in the basal 3 m of the Kamura Formation. The Permian Mitai Formation conformably underlies the Kamura Formation. The uppermost part of the Mitai Formation is usually strongly dolomitized and unfossiliferous but Permian fusulinid Staffella sp. occurs in the weakly dolomitized limestone with foraminifers and calcareous algae near the boundary.As mentioned above we could confirm the Griesbachian in the Shirokawa and the Kamura Formation. This is the first confirmation of the Griesbachian deposited on the submarine volcanic island which accreted to the Yangtze continent in Jurassic. It is quite interesting that the Griesbachian limestone and Upper Permian limestone represent close similarity in lithofacies between two sections. Taho and shioinousou. The dark gray micritic limestone of the Griesbachian deposited in low energy and anoxic environment and light gray micritic limestone of the Upper Permian (Changxingian) sedimented in low energy and oxic environment. The dolomitization occured during the Late Permian and Early Triassic. Less

钻孔（深度50米）。70 mm直径），目的是获取有关Tahokamigumi暴露的Taho石灰岩中二叠纪-三叠纪界线的信息。白川町东宇和郡爱媛县。通过对钻孔岩芯的调查，发现下三叠统格里斯巴赫阶牙形刺Hindeodus minutus。H.parvus.然后呢？Isarcicella isarcica产于大面以下22.80 ~ 23.45 m的深灰色灰岩中，二叠纪的fusulinid Staffella sp.产于大面以下23.50 m的浅灰色灰岩中。我们建议三叠纪石灰岩的大丰组和二叠纪石灰岩的白川组。地层之间的边界是整合的。上二叠统Mitai组和三叠系Kamura组之间的边界出露于盐之野。高千穗町西臼树郡宫崎县。我们确认了小Hindeodus minutus的存在。H.parvus.伊萨尔奇塞拉群岛 ...更多信息 arcica。和Neogondolella carinata，产于Kamura组底部3 m的深灰色石灰岩中，有小型腹足动物。二叠纪三台组整合于Kamura组之下。三台组上部通常为强泥化不含藻类，但二叠纪的fusulinid Staffella sp.产于弱泥化的石灰岩中，在边界附近有有孔虫和钙质藻类。如上所述，我们可以确认白川组和Kamura组中的Griesbachian。这是首次证实格里斯巴赫阶沉积于侏罗纪增生到扬子大陆的海底火山岛上。有趣的是，两个剖面的格里斯巴赫阶灰岩和上二叠统灰岩在岩相上表现出非常相似的特征。太穗和小野秀。格里斯巴赫阶深灰色泥晶灰岩为低能缺氧环境沉积，上二叠统长兴阶浅灰色泥晶灰岩为低能好氧环境沉积。硅化作用发生在晚二叠世-早三叠世。少