【摘要】 基于笔者近20年来在新疆北部地质调查积累的资料,并结合对现有地质地球物理资料的综合分析,本文简要讨论了新疆北部及邻区地壳现今构造格架及其形成过程。该区地壳现今构造格架的基本特征是垂向上具有双层结构,侧向上不同时期具有不同的构造分区。新生代侧向构造分区表现为盆山构造,古生代晚期侧向构造分区总体表现为显生宙造山带与古老地块的镶嵌,具体划分为两个弧形造山系、两个雁行斜列的帚状构造和3条线性造山系,分别属于西伯利亚、哈萨克斯坦、塔里木、喀拉塔格等4个古板块;喀拉塔格古板块是新元古代地壳作为基底的古岛弧与其周围的海洋岩石圈组成的板块,残迹保存在南天山碰撞带之中;阿尔泰山、东准噶尔、准噶尔—吐哈地块是西伯利亚古板块的一部分,西准噶尔和中亚地区是哈萨克斯坦古板块的组成部分,查尔斯克—斋桑带、依连哈比尔尕带和康古尔塔格带,构成了是西伯利亚古板块的南界,南天山是哈萨克斯坦与塔里木古板块的碰撞带。在纵向上,该区地壳被划分为震旦纪至石炭纪、二叠纪至侏罗纪和白垩纪以来的陆内演化等3个构造层。该区构造格架的形成过程包括中元古代至古生代晚期古洋盆的演化与关闭、二叠纪至侏罗纪受古太平洋和古特提斯洋演化影响、以及新生代期间受印度板块与欧亚板块碰撞影响等3个构造阶段;在某些地质时期还与幔源岩浆的底垫对地壳或岩石圈的改造有关。该区前身的古洋盆包括古太平洋和古亚洲洋两个洋盆。从动力学角度看,该区地壳的形成与演化,分别受控于水平方向上板块之间的相互作用和垂直方向上软流圈地幔与上覆岩石圈或地壳的相互作用。结果是不仅使该区大陆地壳的增生有水平的和垂直的两种方式,而且使该区地壳演化表现为挤压和伸展两种方式并存。更多还原

【Abstract】 Based on the geological data the authors collected in northern Xinjiang in the last two decades, together with a comprehensive analysis on the existent geological and geophysical data, they discussed the present-day crustal tectonic framework of northern Xinjiang and adjacent regions and its formation process. The basic present-day tectonic feature is a vertically two-layer structure and horizontally various tectonic subdivisions in different stages. Horizontally, the Cenozoic was characterized by a basin-and-range structure and the late Paleozoic was generally featured by a mosaic of Phanerozoic orogenic belts and ancient blocks, which includes two orocline orogenic systems, two en enchlon broom-like structures and three linear orogenic systems, being separately to the Siberian, Kazakhstan, Tarim and Karatag plates. The Karatag Plate is composed of an island arc with a Neoproterozoic basement and surrounding oceanic lithosphere, and its remnants are preserved in the South Tianshan collision zone and has a range from South Tianshan eastward to Beishan and central Inner Mongolia. The Altay, East Junggar, Junggar—Turpan—Hami blocks are parts of the Siberian Plate, and the western Junggar and Central Asian areas are components of the Kazakhstan Plate. The Charask-Zaysan, Eren Habirga and Kanguertag belts are taken as the southern border of the Seberian Plate and South Tianshan is taken as the collision zone between the Kazakhstan and Tarim plates. Vertically, the crust of the study area is divided into three structural layers, Sinian—Carboniferous, Permian—Jurassic and post-Cretaceous. The formation of this tectonic framework falls into three stages, Mesoproterozoic—late Paleozoic in which there were the evolution and closing of oceans, Permian—Jurassic, which saw the influence of the evolution of the Paleo-Pacific and Paleo-Tethys oceans, and the Cenozoic in which there is the influence of the India—Eurasia collision. Some times in the process there was reworking of diapir of mantle-sourced magma on the crust or lithosphere. Previous oceans in the area include the Paleo-Pacific and Paleo-Asian oceans. Dynamically, the formation and evolution of the crust were controlled horizontally by the interaction between plates and vertically by the interaction between the asthenosphere and overlying lithosphere or crust, and as a result, the accretion of the continental crust was on both the horizontal and vertical directions and the crustal evolution shows both compression and extension.更多还原