造山前、造山和造山后花岗岩的识别  

Criteria for the recognition of pre-, syn-and post-orogenic granitic rocks.

作　　者：张旗[1] 王元龙[1] 金惟俊[1] 贾秀勤[2] 李承东[3] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029 [2]中国科学院高能物理研究所,北京100039 [3]中国地质调查局天津地质矿产研究所,天津300170

出　　处：《地质通报》2008年第1期1-18,共18页Geological Bulletin of China

基　　金：国家“973”项目(编号:2002CB412601);国家自然科学基金项目(编号:40672128)资助

摘　　要：造山前、造山和造山后(或碰撞前、碰撞和碰撞后)花岗岩是花岗岩研究的热门话题。但是,目前关于造山前、造山和造山后的概念存在模糊和矛盾的认识,为此提出了关于造山前、造山和造山后的概念和新的判别方法,并结合非洲、土耳其和巴西的某些实例进行了讨论。着重讨论了青藏高原与碰撞有关的花岗岩,指出青藏高原只存在造山前和造山2个阶段,不存在造山后阶段。认为青藏高原碰撞的时间大概在55Ma左右,25～3Ma的埃达克岩和淡色花岗岩是碰撞阶段形成的。青藏高原25～3Ma的花岗岩的特征暗示青藏高原在25Ma之前已经整体抬升,25Ma之后发育的伸展构造(藏南拆离系、大规模走滑断裂和南北向裂谷)是在青藏高原挤压的大背景下出现的,属于次级的派生构造,其并不能说明青藏高原已经进入伸展减薄和垮塌的碰撞后阶段。Pre-, syn-, and post-orogenic （pre-, syn- and post-collisional） gramtic rocks are a hot topic of granite research. However, vague and contradictory views exist about the concepts of pre-, syn-, and post-orogeny. Therefore the authors present a new concept and discrimination method for pre-, syn-, and post-orogeny and discuss some case histories of Africa, Turkey and Brazil. The focus is on gramtic rocks of the Qinghai-Tibet Plateau related to collision. They point out that only the pre- and syn-orogenic stages occurred on the Qinghai-Tibet Plateau. The collision on the Qinghai-Tibet Plateau took place at -50 Ma. The 25-3 Ma adakite and leucogranite formed in the collision stage, The features of the 25-3 Ma granitic rocks imply that the Qinghai-Tibet Plateau had been uplifted wholesalely before 25 Ma, and the extensional tectonics （such as southern detachment system, large-scale strike-slip faults and N-S-striking rift） that developed after 25 Ma formed by compression in the syn-orogenic stage, rather than crustal extensional thinning and collapse in the post-orogenic stage.

关 键 词：造山前 造山和造山后阶段 地壳厚度 花岗岩 青藏高原 

分 类 号：P588.121[天文地球—岩石学]