大陆演化与花岗岩研究的变革  

Adventure on the research of continental evolution and related granite geochemistry

作　　者：翟明国[1,2,3] 张旗[1,3] 陈国能[4] 王汝成[5] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029 [2]西北大学大陆动力学国家重点实验室,西安710127 [3]中国科学院地质与地球物理研究所岩石圈演化国家重点实验室,北京100029 [4]中山大学地球科学与地质工程学院,广州510275 [5]南京大学地球科学与工程学院,南京210023

出　　处：《科学通报》2016年第13期1414-1420,共7页Chinese Science Bulletin

摘　　要：花岗岩是地球岩石圈区别于太阳系其他行星的标志之一,也是地球岩石圈中陆壳区别于洋壳的重要标志.洋壳形成演化的核心问题是玄武岩,大陆形成演化的核心问题是花岗岩.洋壳的寿命仅2～3亿年,陆壳的寿命长达40～45亿年.大陆花岗岩记录了岩石圈形成演化的各种信息,对于人类认知固体地球具有无法替代的作用.最早的陆壳主要由一类富钠的、以奥长花岗岩-英云闪长岩-花岗闪长岩为主的花岗岩类岩石（TTG）组成.TTG不是早期岩浆海洋结晶分异的产物,也不可能来自地幔岩石的直接熔融.查明TTG的起因即能揭开大陆形成之谜.显生宙大陆演化表现为大陆面积增长和大陆克拉通活化两个方面,两者均伴随海量花岗岩的产出,同时伴随有大规模的成矿作用.花岗岩所凝聚的科学问题是对板块构造理论的巨大挑战,也是固体地球科学理论创新的重大机遇.花岗岩研究从岩石地球化学层面跃升到陆壳演化层面,是研究思维和理论创新的突破,是21世纪花岗岩研究的重大转折.第540次香山科学会议就如何推动花岗岩研究层面的跃升问题展开讨论,汇集智慧、凝聚共识,对我国未来5年和更长时间的花岗岩研究进行顶层设计,进一步推动花岗岩与大陆演化、大陆流变学、大陆动力学和热力学等方面的研究进展.The unique of the lithosphere in the earth is that it contains large amounts of granite, which does not occur elsewhere in the solar system. The continental crust of the earth is mainly composed of granite, whereas the oceanic crust is dominated by basalt. Unlike the short-lived oceanic crust which may have only existed in 200 to 300 Ma on the earth, the continental crust can survive in 4000 to 4500 Ma. The granite in the earth thus may record the history of the formation and evolution of the continental lithosphere of the Earth. The earliest continental crust is composed of tonalitetrondhjemite-granodiorite（TTG） suite, however. TTG is neither a product of fractionation of magma ocean, nor of partial melting of the mantle. The origin of TTG is thus crucial for understanding the origin of continental crust. Extensive continental growth and cratonization occurred in Phanerozoic, which was associated with massive granite production and mineralization. All these issues are difficult to be explained by the current theory of plate tectonics. The answers for the key issues on the granite may trigger the new theory of solid earth sciences. Reworking of continental crust is related to intensive tectonothermal events in the earth as proposed by Prof. Guoda Chen and his ＂platform activation＂ model. Mesozoic large-scaled intracontinental deformation and extensive magmatism in East China may provide an ideal natural laboratory to study the dynamic mechanism of the continental reactivation and to understand plate tectonics and cratonization. Presence of voluminous granite may change the internal structure of the earth and the stability of continental lithosphere, leading to the craton re-activation or destruction. However, it remains unclear how these processes worked in the history of Phanerozoic continental crust. New theory rather than classic plate tectonics is desired to establish to explain the granite issues. The change from routine granite geochemistry to continental growth will make a real breakthrough in the

关 键 词：大陆形成 陆壳演化 克拉通活化 花岗岩 TTG 成矿作用 

分 类 号：P588.121[天文地球—岩石学]