| 晚三叠世昌都盆地构造背景及对成煤作用的控制 |
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| 引用本文： | 曹代勇,宋时雨,马志凯,彭扬文,乔军伟.晚三叠世昌都盆地构造背景及对成煤作用的控制[J].地学前缘,2019,26(2):169-178. |
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| 作者姓名： | 曹代勇 宋时雨 马志凯 彭扬文 乔军伟 |
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| 作者单位： | 中国矿业大学(北京)地球与测绘工程学院,北京,100083;中国矿业大学(北京)地球与测绘工程学院,北京 100083;河北地质大学资源学院,河北 石家庄 050031;中国煤炭地质总局航测遥感局,陕西 西安,710054 |
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| 基金项目： | 中国地质调查局地质调查项目(DD20160187);中央高校基本科研业务费专项(2010YD11) |
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| 摘 要： | 位于西藏东部的昌都盆地是经历石炭纪、二叠纪以及三叠纪多期成煤盆地叠合改造形成的构造盆地，其中以晚三叠世巴贡组含煤地层分布最为广泛。三叠纪时期，盆地两侧的金沙江洋盆与澜沧江洋盆相继闭合，区域构造背景复杂，是决定成煤古地理条件的首要因素。不同的构造背景形成特定的岩浆岩石类型和构造岩浆岩组合。昌都地体两侧晚三叠世火山岩的地球化学特征分析表明，昌都盆地东缘双峰式火山主要受伸展应力控制，形成裂陷，造成地形起伏大，区域沉降幅度大，沉积速率快，不利于发育稳定的成煤环境。盆地西缘与澜沧江洋壳俯冲相关的侵入岩发育，反映在挤压应力背景下形成坳陷，相对简单的基底构造为发生持续稳定的聚煤作用提供了良好的古地理环境。在后期构造作用的控制下，连续的煤层多被错断，呈角度不一、大小悬殊的单斜断块或褶皱产出，在巴贡、夺盖拉等地保存有具工业价值的煤矿点。
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| 关 键 词： | 昌都盆地 构造背景 地球化学 成煤 构造控煤 |
| 收稿时间： | 2018-04-10 |
Tectonic background of the Qamdo Basin and its structural control on coal forming in the Late Triassic |
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| CAO Daiyong,SONG Shiyu,MA Zhikai,PENG Yangwen,QIAO Junwei.Tectonic background of the Qamdo Basin and its structural control on coal forming in the Late Triassic[J].Earth Science Frontiers,2019,26(2):169-178. |
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| Authors: | CAO Daiyong SONG Shiyu MA Zhikai PENG Yangwen QIAO Junwei |
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| Abstract: | The Qamdo Basin in eastern Tibet is a tectonic basin formed from multi-stage coal-forming basins that underwent the superposition transformation of Carboniferous, Permian and Triassic. The coal-bearing strata in the Late Triassic Bagun Formation are widely distributed in the basin. During the Triassic period, the Jinsha and Lancang River ocean basins on either side of the Qamdo Terrane closed successively, resulting in the complex regional tectonic background that largely determined the paleogeographical conditions for coal forming. Different tectonic background yielded specific magma rock types and tectonic-magmatic combinations. The geochemical characteristics of Late Triassic volcanic rocks on either side of Qamdo showed that the bimodal volcanic rock development at the eastern margin of the Qamdo Basin is dominated by stretching stress, forming rift and resulting in large terrain fluctuation and subsidence and fast deposition rate which were disruptive to stable coal-forming environment. The development of intrusive rocks associated with the subduction of Lancang River ocean crust at the western margin of the Qamdo Basin led to a depression under the compressional background; and the relatively simple basement structure provided a good paleogeographical environment for the continuous and stable coal accumulation process. Under the control of later stage tectonic activity, the continuous coal seams were segmented into monoclines or folds with different angles and scales, producing industrial grade coal mining fields in the Bagun, Take Gellar and surrounding areas. |
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| Keywords: | Qamdo Basin tectonic background geochemical coal forming structural controls of coal |
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