| 西藏仲巴县仁多地区早三叠世牙形石及冈底斯西部早三叠世古地理格局 |
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| 关键词:Tibet Gangdise Rendo Mujiuco Formation Early Triassic conodonts paleogeographic pattern |
| 基金项目:国家自然科学基金项目(编号: 41472030);科技基础性工作专项(编号: 2015FY310100);中国地质调查局基础性公益性矿产地质调查项目(编号: DD20160120-02; DD20160120-04; DD20160126);中国地质科学院基本科研业务费项目(编号: J1607) |
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| 摘要: |
| The Early Triassic Conodonts in Rendo Area of Zhongba County, Tibet, and Paleogeographic Pattern of the West Gangdise Block in Early Triassic |
| The increasingly discovered Triassic marine sedimentary data become the main reason to deduce that the paleogeographic model of the Gangdise during Triassic should be a sea rather than a land. However, some geologists still insist that the southern Gangdise block was in an uplifting background, marked as the Longar–Gongbujiangda terrestrial magmatic arc during Early Triassic. This opinion mainly comes from the absent Triassic strata. The Renduo section is located within the Longar uplifting zone, where no Triassic strata were found in the previous research. Through detailed conodont biostratigraphic work, the authors obtained typical Early Triassic conodont specimens assigned into the genus “Pachycladina” from the strata originally ascribed to be the Middle Permian Xiala Formation. So it could be ensured that the Lower Triassic strata were not absent from the study section, but were characterized by dolomite. Regionally, the Lower Triassic dolomite could be correlative to the upper part of the Mujiuco Formation. This finding shows that the lower Triassic strata were well developed in the Rendo area, which quite coincides with the view that the Gangdise during Triassic was in marine depositional setting, and so the Longar uplift viewpoint for Triassic is questionable. Depending on the Lower Triassic sections, the authors depict a litho-paleogeographic pattern showing that two facies could be recognizable in the west Gangdise of the Early Triassic. They are respectively the dolomitic evaporation platform facies and the carbonate platform depression facies. The former is obviously predominant in the spatial distribution. |
| WU Gui-chun,JI Zhan-sheng,SUN Qian,SHI Qiu-yuan,HE Ji-fu,LI Hao,LIU Zhen-yu,GUO An-chen,HOU Zhao-shuo,LI Dong-ze.2018.The Early Triassic Conodonts in Rendo Area of Zhongba County, Tibet, and Paleogeographic Pattern of the West Gangdise Block in Early Triassic[J].Acta Geoscientica Sinica,39(4):409-418. |
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