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关于塔里木盆地志留纪周边构造活动背景一直存在多种看法.本研究利用LA-ICP-MS测试技术获得了塔北隆起泥盆系碎屑锆石的U-Pb年龄,揭示塔北周缘460～414Ma存在强烈的构造事件,其中436～423Ma左右的锆石年龄最为集中,结合前人在盆缘造山带的研究成果,认为奥陶纪末至早、中志留世盆地东北缘存在强烈的构造活动这一期构造活动在盆内有明显的沉积响应:(1)上奥陶统及志留系内部存在多期明显的不整合,反映周边挤压过程在盆内形成的局部隆起;(2)在盆地北部柯坪、英买力、哈得、草湖等地区志留系都发现有由东北向西南注入的河流-三角洲体系,反映盆地东北缘的局部隆升和提供物源;(3)重矿物分析表明志留纪沉积期主要来自再旋回造山带物源.此外,志留系中上部大面积分布的红层可能与周边及盆地的构造隆升、海平面的快速下降等有关.
There are many opinions on the tectonic background of the Silurian tectonics in the Tarim Basin.In this study, the U-Pb ages of detrital zircons from Tabei uplifted Devonian were obtained by LA-ICP-MS, There is a strong tectonic event in 414 Ma. Among them, zircon ages from 436 to 423 Ma are the most concentrated. Combining with the research results of the predecessors in the basin margin orogen, it is considered that there is a strong structure in the northeastern margin of the Middle Silurian basin from the Ordovician to the early During this period, the tectonic activity in this period showed obvious sedimentary response in the basin: (1) there were many obvious unconformities in the Upper Ordovician and Silurian systems, reflecting the local uplift formed in the basin by the peripheral extrusion process; (2) ) In the Silurian of Keping, Ying-Mai Li, Hudson Lake and Caohu Lake in the northern part of the basin, there is a river-delta system injected from northeast to southwest, reflecting the local uplift and source of supply in the northeastern margin of the basin. (3 ) Heavy mineral analysis shows that the Silurian sedimentary period is mainly derived from the source of the gyratozoic orogeny. In addition, the red beds in the middle and upper part of the Silurian may be related to the tectonic uplift of the periphery and basins and the rapid decline of sea level.