青藏高原南部晚新生代板内造山与动力成矿  

Late Cenozoic intraplate orogeny and dynamic metallogeny in the southern Qinghai-Tibet Plateau

作　　者：李德威[1] 

机构地区：[1]中国地质大学地球科学学院,湖北武汉430074

出　　处：《地学前缘》2004年第4期361-370,共10页Earth Science Frontiers

基　　金：中国地质调查局"1:25万定结县幅;陈塘区幅(国内部分)区域地质调查"项目(20001300009231);中国地质调查局"1:25万库赛湖幅;不冻泉幅区域地质调查"项目(200313000005);国家自然科学基金资助项目(40372105)

摘　　要：青藏高原晚新生代构造隆升是板块碰撞成因还是板内造山过程 ,关系到高原形成机制、演化过程以及岩石圈动力学与大陆动力学的关系等一系列重大科学问题。近年来在冈底斯发现多个以斑岩铜矿为主的大型和超大型矿床 ,其成矿时代为 2 0～ 12Ma ,与青藏高原构造隆升时代一致 ,也与笔者10年前以大陆动力学和成矿动力学为理论指导的预测结果吻合。青藏高原南部晚新生代大量的地质、地球物理、矿床等方面的证据根本不支持碰撞造山理论 ,如青藏高原内部伸展边缘逆冲、碰撞与隆升之间时差明显 ,壳内低速层和低阻层发育 ,造山与成盆关系密切 ,板内隆升环境下发生大规模构造变形、岩浆活动和动力成矿等。青藏高原南部晚新生代构造隆升作用是在新特提斯开合转换、碰撞造陆之后 ,在下地壳层流作用的驱动下 ,发生板内造山、地壳增厚、热隆伸展和改造成矿的构造成矿过程 ,大规模的板内金属成矿在 3～ 4Ma以来的均衡隆升、成山过程中进一步改造。It is a key scientific problem that whether the plate collision or the intraplate orogeny caused the Late Cenozoic tectonic uplift, since the problem relates to the mechanism and the evolution of the plateau and to the relationship between the lithosphere dynamics and the continental dynamics in the Qinghai-Tibet plateau. Recently the large and super-large polymetallic deposits, such as the porphyry copper deposits found in the Gangdese belt, were formed during 20～12Ma, which is in accordance with the forecast results predicted on the bases of the continental dynamics and the metallogenic dynamics ten years ago. The collision orogeny is radically not supported by geological, geophysical and metallogenic phenomena, such as the extensive extensional structures in the Qinghai-Tibet plateau, the thrust faults on its border, the obvious time difference between the plate collision and the tectonic uplift, the development of intra-crustal low-velocity layers and low resistance layers, the genetic relationship between orogens and basins, and the strong deformation, large-scale magmatism and massive dynamic mineralization in intraplate setting. The Late Cenozoic tectonic uplift of the southern Qinghai-Tibet plateau was a tectonic-metallogenic process, which was driven by the laminar flow in the lower crust, occurred after the opening-closing transition of Neo-Tethys and the collision epeirogeny, and was made up by the intraplate orogeny, the crustal thickening, the thermal uplifting extension, and the reworking metallogeny. The massive intraplate metallization was further reformed during the balanced uplifting and mountain building since 3～4 Ma.

关 键 词：碰撞造陆 板内造山 下地壳层流 改造成矿 晚新生代 青藏高原南部 

分 类 号：P542[天文地球—构造地质学] P611[天文地球—地质学]