三江地区义敦岛弧碰撞造山过程:花岗岩记录  

Collision-Orogenic Processes of the Yidun Arc in the Sanjiang Region: Record of Granites

作　　者：侯增谦[1] 曲晓明[1] 周继荣 杨岳清[1] 黄典豪[1] 吕庆田[1] 唐绍华[1] 余今杰[1] 王海平[1] 赵金花[1] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037 [2]地质出版社,北京100083

出　　处：《地质学报》2001年第4期484-497,共14页Acta Geologica Sinica

基　　金：国土资源部"九五"科技攻关项目(编号95-02-001);科技部"九五"科技攻关项目(编号96-914-03)

摘　　要：义敦岛弧碰撞造山带是特提斯—喜马拉雅巨型造山带中的一个复合造山带。本文利用义敦岛弧碰撞造山带29个花岗岩体的43件同位素测年数据,结合岩石地球化学特征,建立了造山带花岗岩的时间坐标。初步识别出4套不同成因类型的花岗岩,即印支期弧花岗岩、燕山早期同碰撞花岗岩、燕山晚期A型花岗岩和喜马拉雅期花岗岩。据此,再造了造山带的形成过程与演化历史:印支期的大规模俯冲造山作用(238～210Ma),形成义敦火山岩浆弧;大约自206Ma始,发生弧-陆碰撞,伴随岛弧地壳挤压收缩和剪切变形,发育同碰撞花岗岩;进入燕山晚期(138～73Ma),岛弧碰撞造山带发生造山后伸展作用,形成A型花岗岩带;喜马拉雅期发生陆内造山作用(65～15Ma),岛弧碰撞造山带出现逆冲-推覆和大规模走滑平移,伴随喜马拉雅期花岗岩的侵位和拉分盆地的形成。The Yidun arc collision-orogenic belt is a composue orogenic belt of the giant Tethys-Himalaya orogenic zone. Based on 43 isotopic ages of 29 granite bodies in combination of their petro-geochemistries, the paper established a time coordinate for the granites of the orogenic belt. Four genetic types of the granites were identified as follows: Indosinian arc granites, early Yanshanian syn-collision granites, late Yanshanian A-type granites and Himalayan intra-continental granites. The formation and evolution were reconstructed. A large-scale Indosinian subduction-orogenesis led to the formation of the Yidun magmatic arc (238-210 Ma). From about 206 Ma there occurred arc-continent collision accompanied by compressional contraction and shearing deformation of the arc crust and development of syn-collision granites. In the late Yanshanian epoch (138-73 Ma) post-orogenic extension came into action and resulted in the generation of A-type granites. During the Himalayan (65-15 Ma) intra-continental orogenic movement a large-scale strike-slip thrusting induced the intrusion of granites and development of pull-apart basins.

关 键 词：花岗岩 成因类型 时间坐标 形成背景 岛弧碰撞造山过程 三江地区 岩浆事件 

分 类 号：P542.2[天文地球—构造地质学] P588.121.1[天文地球—地质学]