【摘要】 天山是研究现今陆内造山作用及过程、陆内变形、陆内强震及其预测等大陆动力学问题的理想实验场。西南天山和塔里木之间的新生代褶皱 -逆断裂带基本上由一南冲弧形推覆构造系统和一向北反冲的构造系统组成 ,由北而南主要由以下 4个运动学单元组成 :(1)新生代复活的喀拉铁热克山 -天山南脉古生代造山带 ,其快速变形和抬升可能起始于 2 3～ 2 6Ma前 ,持续至 13～ 16Ma前。 (2 )向南逆冲的西南天山前陆薄皮主冲断带 ,包括木兹杜克弧形薄皮推覆体和依柯冲断带 ,前者代表了向南薄皮逆掩的天山型岩系 ,地表主要表现为一系列的飞来峰群 ,在 14Ma前曾有过大规模活动 ,最小缩短量约为 2 0～ 35km ,最小缩短速率约为 1.4～ 2 .7mm a ;后者代表了向南叠瓦状薄皮逆冲推覆的前陆古生代基底 (塔里木地台型沉积岩系 )卷入构造 ,其西段在距今 14Ma时曾有过强烈活动。两者共同组成了一复杂的双重构造 ;新生代地层也卷入变形。 (3)喀什 -阿图什弧形反冲褶皱 -逆断裂带 ,由 3排向北 (天山 )反冲的左阶雁列展布的第四纪地表滑脱褶皱组成 ,仅在大山口以西发育。该构造带形成于距今约 1.4Ma以后。依什拉克喀拉乌尔断裂以南 ,博古孜河剖面的最小缩短速率约为 5 .8mm a ,翁库尔剖面的最小缩短速率约为 8.6mm a。 (4 )塔里木克拉?更多还原

【Abstract】 The Tianshan is an ideal nature laboratory to understand intracontinental mountain building. The present topography of the Tianshan was created during Cenozoic times as a result of the India-Asia collision. Up to 9 km of Cenozoic sediments have accumulated along the southwestern margin of the Tianshan in the NW Tarim Basin and have been folded into a suite of elongate anticlines and synclines. This deformation zone has two remarkable, oppositely vergent arcuate fold-and-thrust systems (Kepingtage-Yishlakekalawuer and Kashi-Artux fold- and-thrust belts) reaching from east of Kalpin to west of Kashi. Paleozoic to Cenozoic strata is included in this deformation. From north to south, this deformation zone is characterized by four main kinematic elements: (1) A hanging-wall block (Maidan-Karatieke fault) that represents the Cenozoic reactivation of a late Paleozoic thrust system. Apatite fission track data suggest that this deformation initiated at 26 Ma and continued to 16～13 Ma. (2) A south vergent duplex where Devonion-Permian strata exposed on the roof thrust(the Muziduke thin-skinned thrust system) were derived from the Tianshan. This overthrusting initiated prior to 14 Ma with an inferred minimum basinward displacement of ～20～35 km and a slip rate of ～1.4～2.7 mm/a. The floor thrust(the Kepingtage-Yishlakekalawuer thrust system) consists of an imbricated thrust stack where slices of Paleozoic strata derived from the former Tarim platform are thrust south toward the basin. (3) The Kashi-Artux fold-and-thrust system where thrusting and folding verge toward the Tianshan. A preliminary magnetostratigraphy indicates that folding began at about 1.4 Ma, the minimum shortening rate is about 5.8 mm/a at the Boguzi section, and 8.6 mm/a at the Wengkuer section based on balanced cross-section to the south of the Yishilakekalawuer thrust. (4) A foot-wall block (Tarim craton) that dips gently northwest below the sediment-filled southern Tianshan basin and generally has little internal deformation. The underlying Tarim Block is not homogeneous: there are variations in crustal strength and in the locations of long-lived basement fractures or weaknesses that have produced an irregular basement configuration beneath the basin. These have exerted a control on the deposition of Cenozoic sediments across the basin, leading to major variations in the relief, stratigraphy, and deformation pattern along the northwestern margin of the Tarim Basin. The recorded strong earthquakes have been concentrated on the crustal-scale Maidan-Karatieke fault and the Artux fault and fold-and-thrust zone between them.更多还原