| 吐鲁番-哈密盆地陆源碎屑沉积环境及物源分析 |
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| 引用本文： | 邵磊,李文厚.吐鲁番-哈密盆地陆源碎屑沉积环境及物源分析[J].沉积学报,1999,17(3):435-442. |
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| 作者姓名： | 邵磊 李文厚 |
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| 作者单位： | 1 同济大学海洋地质开放实验室 上海 200092; |
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| 摘 要： | 吐鲁番-哈密盆地从晚二叠世到晚第三纪经历了复杂的，多旋回的沉积构造演化历史，造成主要地层间均以不整合为界。盆地内沉积相类型丰富，沉积环境随时间的推移而发生改变。在晚石炭世，盆地北部为浅海环境；到晚二叠世，沉积环境由海相转变为陆相，并在上二叠统下部形成大量冲积相或河流相粗碎屑沉积；在三叠纪，沉积物主要形成于冲积相或河流-湖泊环境中，古气候则由干旱转为温暖湿润。早、中侏罗世，沉积环境以湖泊-沼泽相为主；到晚侏罗世，则以辫状河流相为主及干旱气候为特征。在白垩纪，盆地的沉积范围大为缩小，以湖泊环境为主；第三纪，沉积范围则扩大到整个盆地，沉积相以辫状河流及冲积相为特征，沉积气候干旱，局部地区接受了盐类沉积。古流向分析显示，吐-哈盆地具有复杂的沉积搬运体系。在盆地南侧，沉积物搬运方向总是由南向北，表明觉罗塔格山是盆地的主要物源区；而在盆地北侧，博格达山自晚侏罗世开始隆起，构成盆地的另一新的物源区，沉积物搬运方向由北向南。在白垩及第三纪，博格达山成为盆地的主要物源区。
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| 关 键 词： | 碎屑岩 沉积环境 古流向分析 吐鲁番- 哈密盆地 |
| 收稿时间： | 1998-03-10 |
Sedimentary Environments and Source Rock Analysis of the Turpan Basin |
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| Institution: | 1 Laboratory of Marine Geology,Tongji University,Shanghai 200092;2 Department of Geology,Northwest University,Xi'an 710069 |
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| Abstract: | The Turpan Basin is located in the eastern part of the Tian Shan and has a complex polycyclic sedimentary and tectonic history from the Late Permian to the Late Tertiary.Main stratigraphic boundaries follow in general tectonically induced sedimentary cycles,which are bounded by unconformities.More than 10 000 metres of clastic sediments were accumulated during the evolution of the basin.The sedimentary facies are abundant and the sedimentary environments changed with time.The oldest parts of the true basin fill are of Late Permian age.They and mostly nonmarine deposits and overlay unconformably Upper Carboniferous volcanic rocks and consist of lacustrine and fluvial dark mudstones,siltstone,sandstone and conglomerate.The Triassic strata consist of red coarse clasts in the lower part and dark,fine clastic sediments with coal and coal streaks in the upper part, indicating alluvial and lacustrine-fluvial environments with climate change from arid to humid during the Triassic.The Jurassic sediments form the most widely distributed and thickest part of the Turpan Basin,as well as the most important productive sequences of oil,gas and coal,The Lower and Middle Jurassic sediments consist of grey and green fine clastic coal-bearing rocks which were deposited in a lacustrine-swamp environment.The Upper Jurassic consists of variegated coarse clasts rocks,reflecting piedmontfluvial environment with arid climate.In the Cretaceous,the sedimentary range was more limited and the sedimentary environment belongs to a lacustrine system.The Tertiary strata are distributed through the entire basin and are the youngest of the basin fill investigated in this study.Conglomerate and sandstone are dominant in the lower part and deposited in a braided fluvial/alluvial environments,while mudstone and silty mudstone are dominant in the upper part and are a lacustrine deposition.Local interlaid gypsum beds and salt beds with red mudstone indicate a deposition in an arid climate and a local salt-water lake environment. Paleocurrent analysis reveals a complex pattern of sediment fluxes into the basin.Along with the tectonic variation,the source rock regions of the basin varied with time. From Permian to Jurassic,the Jueluotage Shan was the dominant source rock region for the Turpan Basin.The locally uplifted areas of the Bogda Shan(e.g.at Taoshuyuan)were only minor providers of source rocks .The paleocurrent directions were from south to north.The Qitai paleouplift was an important provenance area for the northern region of the basin,which leading to the transportation of sediments from north to south .Since the Latest Jurassic,the Bogda Shan gradually folded and uplifted,building another source rock region for the basin.The paleocurrent directions were from north to south.In the Cretaceous and Tertiary,the Bogda Shan was an important source rock region.This region was continually strongly uplifted in the Cenozoic age and the dominant source rock region for the basin with transport directions from north to south.In the Hami Sag,the Haerlike Shan was a continuously eroding region and an ever important provenance area,along with the Jueluotage Shan.The paleocurrent directions were always from north to south. |
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