东昆仑印支期中酸性岩浆岩特征及构造背景  

Characteristics and tectonic setting of the Indo-Chinese epoch intermediate-acidic magmatic rocks in Eastern Kunlun

作　　者：陶斤金[1,2] 赖健清[1,2] 

机构地区：[1]中南大学有色金属成矿预测教育部重点实验室,长沙410083 [2]中南大学地球科学与信息物理学院,长沙410083

出　　处：《西部资源》2014年第2期189-192,共4页Western Resources

摘　　要：东昆仑地区出露大面积多期次的岩浆岩体,构成一条巨大的岩浆岩带。通过对东昆仑近年来获得的印支期中酸性岩浆岩锆石U-Pb及部分39Ar-40Ar测年结果的分析,东昆仑印支期岩浆岩可以分为早期和晚期2个形成阶段。早期中酸性岩浆岩形成于260-230Ma左右,岩性主要为英云闪长岩、花岗闪长岩和二长花岗岩;晚期中酸性岩浆岩形成于230-195Ma左右,岩性主要正长花岗岩和二长花岗岩。这些广泛分布的中酸性岩浆岩表明东昆仑地区在印支期经历了复杂的岩浆和构造作用过程,早期岩浆岩的形成与东昆仑洋壳大规模俯冲碰撞有关,晚期岩浆岩的形成与东昆仑碰撞后的伸展作用有关。A large area of multi- stage magmatic rocks constitute a huge magmatic belt in the Eastern Kunlun. A summary of the recently obtained zircon U- Pb or39Ar-40Ar ages of Indo- Chinese epoch intermediate- acidic magmatic rocks in Eastern Kunlun indicates that two stages of magmatism, including early stage(260- 230Ma) and later stage(230- 195Ma).The main components of the early stage are tonalite, granodiorite and adamellite. Rocks from the late stage are composed mainly of syenogranite and adamellite. The wide distribution of the intermediate- acidic magmatic rocks indicates a very complex tectonomagmatic history of the Eastern Kunlun during the Indo- Chinese epoch. The early stage rocks are probably related to massive subduction of oceanic crust collide in the Eastern Kunlun. The formation of later stage rocks might have resulted from post- collisional/post- orogenic lithospheric extension after collision.

关 键 词：东昆仑 印支期 中酸性岩浆岩 构造背景 

分 类 号：P588.1[天文地球—岩石学]