Environmental change and process of mass extinction of Paleozoic oranisms in Yangtze Block during Late Paleozoic to Early Mesozoic time

扬子地块晚古生代至早中生代环境变化与古生代生物大灭绝过程

• 批准号: 03041069
• 负责人: YAO Akira
• 金额: $ 1.92万
• 依托单位: Osaka City University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03041069/
• 关键词: Yangtze Block; Permian-Triassic; Environmental change; Paleozoic organism; Mass extinction; Paleontology; Facies analysis

Environmental change and process of mass extinction of Paleozoic organisms in Yangtze Block during Late Paleozoec to Early Mesozoec timeThe main purpose of this project was to study the environmental changes and the processes of mass extinction of Paleozoic or, anisms at the end Permian. Emphasis was placed to clarify the vertical distributions of such mega- and microfossils as corals, radiolarians, conodonts and fusulinids through continuous straligraphc successions of the Permian to Triassic in the Yangize Block. In addition, we aimed to reconstruct the sedimentary environments across the Permian-Triassic boundary.The studied areas were west Guizhou and central to west Guangxi both on the Yangize Block. Following twelve sections (1-7 in Guizhou and 8-12 in Guangxi) were studied.1. Chouzushan (17km north of Anshun), G-H-I, 20m ; 2. Maoshachin (34km south of Ziyun), D-G-I, 400m ; 3. Saiwa (18km south of Ziyun), P3, 1100m ; 4. Taizucho (Guiyang), E-G-H-I, 240m ; 5. Duraying (Guiyang), C … More -E-G-I-J, 40m+ ; 6. Dwansha (85km south of Guiyang), D-G-I-K, 220m ; 7. Nashui (40km southwest of Luodian), D3-T1 ; 8. Tungtienyien (20km south of Liuzhou), A-B, 40m+ ; 9. Niumuping (10km northeast of Liuzhou), F-H, 200m+ ; 10. Linalang (20km east-northeast of Pingguo), D3-T1, 450m+ ; 11. Tsiping (20km northwest of Pingguo), A-C-F-K, 70m+ ; 12. Guofualungchiu (20km west of Pingguo), P-T1, 50m+(A) Chibsia Formation [P21] ; (B) Kufebg Fm. : (C) Maokou Fm. [P2, 2] ; (D) Wujiaping Fm. : (E) Lungtan Fm. : (F) Hoshan Fm. [P31] ; (G) Changxing Fm. : (H) Talung Fm. [P32] ; (I) Tayeh Fm. : (J) Yehlang Fm. : (K) Luolou Fm. [T11]In each section, litho- and biostratigraphic studies and systematic sampling of fossils and sedimentary rocks were carried out.1. LithofaciesThe Upper Permian is divided into three lithofacies ; carbonate, clastic and reworked-carbonate, and clastic and siliceous facies, which are equivalent to platform, slope and basin sediments, respectively. The uppermost Permian is conformably overlain by the Lower Triassic clastic rocks.2. Sedimentary faciesThe Lungtan Formation reveals coarsening-upward sequences of a deltaic origin as well as occasional occurrences of tidal flat deposits. The calcareous turbidite facies locally shows cyclic sedimentation demonstrated stacked thinning-upward sequences. Clastic facies of the Lower Triassic is interpreted as the shallow marine deposits as revealed by common presence of hummocky cross-stratification.3. BiofaciesRugose corals are common in the Middle Permian, but are sparse in the Upper Permian (Wujiaping and Changxin, Formations). Corals are facies-dependent and are variable in taxonomic composition from area to area. The uppermost Permian limestones occasionally contain abundant sponges and show bird's-eye structure. Radiolarians are abundant, especially in the Talung Formation of siliceous rocks. Less

扬子地块古生代晚期至中生代早期的环境变化和生物大灭绝过程本项目的主要目的是研究古生代或二叠纪末的环境变化和生物大灭绝过程。通过二叠纪的连续层序序列，阐明珊瑚、放射虫、牙形刺和福斯林科等巨型和微型化石的垂直分布此外，我们的目标是重建跨二叠系-三叠系边界的沉积环境。研究区域为阳泽地块的黔西和广西中部至西部，共12个剖面（贵州1-7​​）。广西8-12）进行了研究。 1. 丑祖山（安顺以北17km），G-H-I，20m； 2. 茅沙钦（34km） 3.赛瓦（紫云以南18公里），P3，1100m；4.太祖町（贵阳），E-G-H-I，240m；5.都拉营（贵阳），C…更多-E-G-I-J，40m+；6. D-G-I-K，220m；7.那水（罗店西南40公里），D3-T1；8.铜田驿（柳州以南20公里），A-B，40m+；9.牛木坪（柳州东北10公里），F-H，200m+；平果县东北偏东20公里）， D3-T1, 450m+; 11. 齐平(平果西北20km), A-C-F-K, 70m+; 12. 国富隆丘(平果以西20km), P-T1, 50m+(A) 赤布西亚组[P21]; : (C) 茅口组[P2, 2] ; (D) 龙滩组 : (F) 和山组 [P31] ; (H) 塔隆组 ; : (J) 野郎组 : (K) 罗楼组 [T11]在每个剖面中，对化石和生物地层进行了系统采样。 1.岩相上二叠统分为碳酸盐岩、碎屑岩和改造碳酸盐岩、碎屑岩和硅质岩相，分别相当于台地、盆地斜坡和沉积物。 2．沉积相龙潭组也揭示了三角洲起源的粗化向上层序。局部出现钙质浊积岩沉积，表明下三叠统碎屑岩相为浅海沉积，表现为丘状交错层理的普遍存在。中二叠统珊瑚常见，上二叠统珊瑚稀疏（吴家坪和长兴珊瑚组）。取决于相，并且不同地区的分类组成也不同。最上面的二叠纪石灰岩偶尔含有丰富的海绵，并显示出丰富的放射虫，特别是在硅酸盐岩的塔隆组中。