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

扬子地块晚古生代至早中生代环境变化及古生代生物大灭绝过程本项目的主要目的是研究二叠纪末古生代或无性生物的环境变化及大灭绝过程。重点通过阳泽地块二叠系至三叠系的连续层位序列，明确了珊瑚、放射虫、牙形刺、毛细石等巨微化石的垂直分布。此外，我们的目标是重建跨越二叠纪-三叠纪边界的沉积环境。研究区域为阳泽地块的贵州西部和广西中西部。研究了以下12个部分（贵州1-7​​，广西8-12）。 1．臭祖山（安顺以北17公里），G-H-I，20m； 2、茅沙钦（紫云以南34公里），D-G-I，400m； 3、赛瓦（紫云以南18公里），P3，1100m； 4. 太津町（贵阳），E-G-H-I，240m； 5. 杜瑞英（贵阳），C … More -E-G-I-J，40m+； 6、大万莎（贵阳以南85公里），D-G-I-K，220m； 7.那水（罗店西南40公里），D3-T1； 8. 铜天庵（柳州以南20公里），A-B，40m+； 9、牛木坪（柳州东北10公里），F-H，200m+； 10.里那朗（平果东北偏东20公里），D3-T1，450m+； 11、齐平（平果西北20公里），A-C-F-K，70m+； 12. 国富阿隆丘（平果以西20km），P-T1，50m+(A) Chibsia组[P21]； (B) 库费布格组。 ：(C)茅口组。 [P2，2]； (D)吴家坪组：(E)龙潭组。 : (F) 鹤山组[P31]； (G) 长兴组: (H) 达隆组。 [P32]； （一）塔耶组。 : (J) 野郎组。 : (K) 罗楼组[T11]在每个剖面中，都进行了岩石和生物地层学研究以及化石和沉积岩的系统采样。1．岩相上二叠统分为三个岩相；碳酸盐岩相、碎屑岩相和再造碳酸盐岩相、碎屑岩相和硅质相，分别相当于台地沉积、斜坡沉积和盆地沉积。二叠纪最上部被下三叠统碎屑岩整合覆盖。2．沉积相龙潭组揭示了三角洲起源的粗化向上层序以及偶尔出现的潮坪沉积物。钙质浊积岩相局部表现为循环沉积，表现为堆积的向上减薄层序。下三叠统碎屑岩相被解释为浅海相沉积，表现为普遍存在的丘状交错层理。3．生物相 皱纹珊瑚常见于中二叠统，但在上二叠统（吴家坪组和长兴组）稀疏。珊瑚取决于相，并且不同地区的分类组成各不相同。最上面的二叠纪石灰岩偶尔含有丰富的海绵并呈现鸟眼结构。放射虫非常丰富，特别是在硅质岩石的塔隆组中。较少的