云南丘北地区下三叠统洗马塘组生物组合及其环境意义
发布时间：2018-08-09 16:44
【摘要】：本论文以云南丘北地区下三叠统洗马塘组为主要研究对象,系统研究了该地区洗马塘组的岩石地层、生物地层及沉积环境。研究重点是洗马塘组生物化石组合和环境意义,并在此基础上探讨其对P/T大灭绝后早三叠世生物复苏的意义。本次研究主要采取野外调查与室内实验相结合的方法,运用岩石学、沉积学、古生物学等理论作为指导,实测了多条洗马塘组剖面,采集了大量化石,取得了诸多新的发现和进展,全面提升了对洗马塘组的研究认识。取得的主要认识有:(1)通过剖面实测,对洗马塘组岩性有了新的认识。在洗马塘组底部发现一套厚层鲕粒灰岩和数层火山成因的钾质斑脱岩,修正了前人在岩性描述方面的认识。(2)在洗马塘组一段泥岩中发现了大量古生物化石,包括双壳类、腹足类、腕足类、叶肢介、海蛇尾类棘皮动物、节肢动物、菊石、牙形石、分类不明动物化石,以及植物等。其中海蛇尾类棘皮动物和肋木系首次在洗马塘组发现。这些化石的发现为研究P/T大灭绝后早三叠世生物复苏提供了重要的材料。(3)对洗马塘组生物地层进行了研究,识别出牙形石带分子Isarcicella staeschei,重新厘定了双壳化石带,证实洗马塘组时代属于早三叠世印度期Gresbachian亚期,可与四川贵州等地广泛分布的飞仙关组对比。根据碎屑锆石U-Pb测年获得了年龄数据为249±5Ma。(4)结合古生物学和沉积学特征,认为丘北地区洗马塘组属于浅海环境,离陆地较近,是P/T大灭绝及其后早三叠世全球极端环境下的一个生物避难所,属于正常富氧环境,为当时生物的迅速复苏提供了一个有利的场所。
[Abstract]:In this paper, the Lower Triassic Simatang formation is taken as the main research object, and the lithostratigraphy, biostratigraphy and sedimentary environment of the Qimatang formation in this area are systematically studied. The emphasis of this study is on the fossil assemblage and environmental significance of the Qimatang formation, and on the basis of this, the significance of the fossil assemblage to the early Triassic recovery after the P- / T mass extinction is discussed. This study mainly adopts the method of combining field investigation with laboratory experiments, using the theories of petrology, sedimentology and paleontology as the guidance, measuring several sections of Ximatang formation and collecting a large number of fossils. Many new discoveries and advances have been made, and the research knowledge of Ximatang formation has been improved. The main results are as follows: (1) the lithology of the Qimatang formation has been acquired through the measurement of the profile. A set of thick oolitic limestone and several layers of volcanogenic potash porphyry were found at the bottom of the Simatang formation, which modified the previous understanding of lithology description. (2) A large number of paleontological fossils, including bivalves, were found in the mudstone of the first member of the Simatang formation. Gastropods, brachiopods, phyllodes, sea serpentine echinoderms, arthropods, chrysanthemums, conodonts, fossils of unknown species, and plants. Among them, echinoderms of sea snaketail and Leymus were first found in Ximatang formation. The discovery of these fossils provides important materials for the study of early Triassic biorecovery after the P/ T mass extinction. (3) the biostratigraphy of the Ximatang formation was studied, the conodont zone molecule Isarcicella staeschei was identified, and the bivalve fossil belt was redefined. It is proved that the Simatang formation belongs to the early Triassic Indian Gresbachian substage, which can be compared with the Feixianguan formation widely distributed in Sichuan and Guizhou. According to the U-Pb dating of clastic zircon, the age data is 249 卤5 Ma.The (4) combined with paleobiology and sedimentology, it is considered that the Qimatang formation in Qiubei area belongs to the shallow sea environment and is near to the land. It is a biological refuge in the P/ T extinction and the early Triassic global extreme environment, which belongs to the normal oxygen-enriched environment and provides a favorable place for the rapid recovery of life at that time.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q91;P534.51
本文编号：2174699
[Abstract]:In this paper, the Lower Triassic Simatang formation is taken as the main research object, and the lithostratigraphy, biostratigraphy and sedimentary environment of the Qimatang formation in this area are systematically studied. The emphasis of this study is on the fossil assemblage and environmental significance of the Qimatang formation, and on the basis of this, the significance of the fossil assemblage to the early Triassic recovery after the P- / T mass extinction is discussed. This study mainly adopts the method of combining field investigation with laboratory experiments, using the theories of petrology, sedimentology and paleontology as the guidance, measuring several sections of Ximatang formation and collecting a large number of fossils. Many new discoveries and advances have been made, and the research knowledge of Ximatang formation has been improved. The main results are as follows: (1) the lithology of the Qimatang formation has been acquired through the measurement of the profile. A set of thick oolitic limestone and several layers of volcanogenic potash porphyry were found at the bottom of the Simatang formation, which modified the previous understanding of lithology description. (2) A large number of paleontological fossils, including bivalves, were found in the mudstone of the first member of the Simatang formation. Gastropods, brachiopods, phyllodes, sea serpentine echinoderms, arthropods, chrysanthemums, conodonts, fossils of unknown species, and plants. Among them, echinoderms of sea snaketail and Leymus were first found in Ximatang formation. The discovery of these fossils provides important materials for the study of early Triassic biorecovery after the P/ T mass extinction. (3) the biostratigraphy of the Ximatang formation was studied, the conodont zone molecule Isarcicella staeschei was identified, and the bivalve fossil belt was redefined. It is proved that the Simatang formation belongs to the early Triassic Indian Gresbachian substage, which can be compared with the Feixianguan formation widely distributed in Sichuan and Guizhou. According to the U-Pb dating of clastic zircon, the age data is 249 卤5 Ma.The (4) combined with paleobiology and sedimentology, it is considered that the Qimatang formation in Qiubei area belongs to the shallow sea environment and is near to the land. It is a biological refuge in the P/ T extinction and the early Triassic global extreme environment, which belongs to the normal oxygen-enriched environment and provides a favorable place for the rapid recovery of life at that time.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q91;P534.51
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1 周机灵;刘晓东;;云南丘北洗马塘金异常特征及矿化层位[J];云南地质;2013年01期
，本文编号：2174699
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