大陆克拉通早期构造演化历史探讨:以华北为例  

The Early Precambrian Tectonic Evolution of Continental Craton: A Case Study from North China

作　　者：李江海[1] 牛向龙[1] 程素华[1] 钱祥麟[1] 

机构地区：[1]北京大学地球与空间科学学院教育部造山带与地壳演化重点实验室,北京100871

出　　处：《地球科学（中国地质大学学报）》2006年第3期285-293,共9页Earth Science-Journal of China University of Geosciences

基　　金：国家自然科学基金项目(No.40472097)

摘　　要：大陆早期构造演化的研究一直是大陆地质学研究的焦点问题.在华北克拉通基底构造1∶200万编图研究基础上,本文开展基底断裂边界、构造样式及后期叠加关系的研究,借鉴比较大地构造理论,对华北克拉通基底重新进行了构造区划.结合标志性构造单元及其时代、同位素年龄数据库的综合研究,提出华北早期构造格局演化及其重大构造热事件.华北克拉通基底主要由大面积的新太古代TTG杂岩及表壳岩系组成,新太古代涉及活动陆缘环境的大规模陆壳增生及不同微陆块的碰撞聚合过程,造成新太古代末期陆壳迅速增生和克拉通化.古元古代初期开始伸展裂解和早期盖层发育阶段,古元古代晚期发生微陆块碰撞缝合,形成超级克拉通,并在克拉通西北边缘发生强烈改造作用.1.84Ga前后,华北克拉通经历最强烈的一次伸展裂解过程,从超级克拉通裂解,开始了独立的构造演化,在伸展构造背景下,克拉通基底被强烈隆升冷却,经历风化剥蚀,发育沉积盖层.以上构造格局及其构造热事件提供了早期超级大陆再造研究的构造制约条件.The early tectonic evolution of craton has been the target topic for continental geology. Based on a preliminary analysis on the tectonic map （1 ： 2 000 000） of North China craton （NCC） basement, we try to investigate its tectonic boundades, structural pattern, and late stage reworking. Guided by the framework of modern plate tectonics, the NCC basement is divided into different tectonic units. It is suggested here that some key geological units （KGU）, with distinct tectonic setting and geological origin, may well preserve information of its early tectonic history. With the high-precision isotopic age dating of KGU, a new timetable of geological and geochrological events has been defined for the Early Precambrian geology of NCC. In addition, several major tectonothermal episodes can be revealed by the synthesis of available age data with TTG-granite gneiss and mafic volcanics. Therefore, the Early Precambrian tectonic evolution of NCC is documented by a consideration of both regional geological research and age dating As indicated by widespread geological research and high-precision geochronology, NCC＇s basement was mainly consisted of Neoarchean TTG complex and supracrustal sequences, associated with rapid crustal accretion within the setting of active continental margins and collisions between different blocks. As a result, it became stabilized at the end of the Archearn. In the Early Paleoproterozoic, the NCC began to be dominated by an extensional tectonic regime, characterized by the development of early cover. In the Late Paleoproterozoic, the NCC collided with another block in the north, with formation of a supercraton, which caused a strong tectonotherrnal reworking to its passive margin in the northwestern part of NCC. At about 1.84 Ga, the NCC underwent extension, recorded its dispersal from a supercraton. After that, it began its tectonic evolution independently, its basement was intensely uplifted and eroded, with development of sedimentary cover. The Early Precarnbrian tectonic framew

关 键 词：板块构造 构造区划 构造热事件 活动陆缘 伸展作用 超级大陆 

分 类 号：P542[天文地球—构造地质学]