Analysis of the Late Paleozoic and Mesozoic Paleocurrents and It′sConstructional Significance of the Northern Bogdashan, Xinjiang
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摘要: 新疆准噶尔盆地南缘博格达山北缘地区古水流方向在晚古生代到中生代期间发生过三次重要的转变。晚石炭世晚期以前指向南，晚石炭世晚期到二叠纪期间指向东、南东东向，三叠纪—侏罗纪指向南，白垩纪及其以后指向北。结合盆地物源和沉积环境分析，博格达山北缘自晚古生代以来可划分为四个构造演化阶段，古流向转折期为盆地各期构造演化的分界线，它们是盆地对周缘造山带构造演化沉积响应的重要记录。另一方面，古水流转折时间资料的获得，对准噶尔盆地周缘不同构造带的隆升时代是一个非常重要的限定。晚石炭世晚期至二叠纪，古水流资料指示沉积物主要来自准噶尔盆地西部，准噶尔盆地西—西北缘强烈隆升，自三叠纪早期开始到侏罗纪晚期，准噶尔盆地北缘抬升，博格达山北缘沉积物主要来自北方；侏罗纪晚期到白垩纪，古水流指示沉积物主要来自盆地南部，博格达山隆起并遭受剥蚀。然而，什么原因造成石炭纪末以来，准噶尔盆地周缘几个造山带顺时针方向依次隆起，有待进一步研究。Abstract: The northern Bogdashan is located in the south of the Junggar Basin and in the north of Tian Shan. Paleocurrents analysis reveals that paleocurrent direction had three important abrupt transformations from the Neopaleozoic to the Cenozoic. Before the Late Carboniferous, the paleocurrent directions were from north to south. During the Permian, the paleocurrent directions were from west to east or form northwest to southeast. From the Triassic Period to the Jurassic, the paleocurrent directions were from north to south. From the Cretaceous to the Cenozoic, the paleocurrent directions was form south to north. The northern Bogodashan may be divided four tectonic evolution stages form the Neopaleozoic to the Cenozoic by integrated analysis paleocurrent，provenance and sidimentary environment. The transition phase of paleocurrent directions was not only the boundary of each stages of basin tectonic evolution but also important sedimentary record of orogenic belt evolution around the area. Furthermore, the transition time of the paleocurrent directions may restricts when structural belt around Bogodashan had uplifted. At the end of the late Carboniferous, the north western Junggar Basin had be intensity uplift and subsequently sediments fluxes into the basin form west to east. At begin of the Triassic Period, the northern jungar basin was uplifted and it provided clastic sediments for basin from the Triassic to the Jurassic. At the end of the Jurassic, the Bogodashan began to be uplifted and provided clastic sediments for besides of the Bogodashan. Why had the orogenic belt be uplifted clockwise around of the Junggar Basin? It would be researched further.
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Key words:
- Xinjiang /
- the Junggar Basin /
- paleocurrent /
- sedimentary environments /
- basinmountain coupling
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