三江地区义敦岛弧造山带演化和成矿系统  

Tectonic Evolution and Mineralization Systems of the Yidun Arc Orogen in Sanjiang Region, China

作　　者：侯增谦[1] 杨岳清[1] 曲晓明[1] 黄典豪[1] 吕庆田[1] 王海平[1] 余金杰[1] 唐绍华[1] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037

出　　处：《地质学报》2004年第1期109-120,共12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：义敦岛弧是喜马拉雅巨型造山带中的一个复合造山带,它经历了印支期洋壳俯冲造山、燕山湖弧-陆碰撞和喜马拉雅期陆内走滑作用诸演化历史。可能由于洋壳板片俯冲角度不同,义敦晚三叠世古岛弧带(206～237 Ma)南北两段具有不同的发育历史,北段昌台弧以发育孤间裂谷为特色,具张性弧特征,发育扩张环境流体聚敛成矿系统,形成VMS型Zn-Pb-Cu矿床和浅成低温热液型Ag-Au-Hg矿床;南段中甸弧不发育弧后盆地,但广泛发育钙碱性弧火山岩-玢岩-斑岩杂岩系和挤压环境岩浆-流体成矿系统,形成斑岩型-夕卡岩型铜多金属矿床。在三叠纪-侏罗纪之交的弧-陆碰撞作用中,早期大陆板片俯冲形成同碰撞花岗岩带(约200 Ma),晚期造山后伸展作用,形成A型花岗岩带(75～138 Ma),伴随扬子大陆板片俯冲而发生的强烈剪切和推覆,在甘孜-理塘蛇绿混杂带发育挤压剪切环境流体聚敛成矿系统,形成剪切带型金矿。伴随造山后伸展和A型花岗岩侵位,发育伸张环境岩浆-流体聚敛成矿系统,主要形成夕卡岩型锡矿和构造破碎带热浪脉型银多金属矿床。印度-亚洲大陆碰撞在义敦造山带主要表现为陆内走滑作用,并控制碱性花岗岩和花岗斑岩的发育(50～30 Ma),伴随斑岩型金矿的形成。As a composite erogenic belt of the Himalaya giant orogenic zone, Yidun arc, Sanjiang region (means three rivers region, i.e. : Jinsha River, Nujiang River and Lancang River), experienced an evolution history including Indosinian subduction orogeny of oceanic crust, Yanshanian arc-continental collision orogeny and Himalayan intra-continental strike-sliding shearing. Probably due to different subduction dipping degrees, the Yidun old arc belt of late Triassic (206 ~ 237 Ma) has a different development history in its northern and southern segments. Changtai arc in the northern segment was characterized by intra-arc rift with expanding nature and developed a fluid convergent ore-foming system in an extentional environment, which formed. VMS-type Zn-Pb-Cu deposits and epithermal Ag-Au-Hg deposits. Zhongdian arc of the southern segment lacked back-arc basin, but had extensive calc-alkaline complex distribution of arc volcanics-porphyry-porphyrite, which formed porphyry-skarn-type Cu-polymetalic deposits. During the arc-continental Collisional process of Triassic-Jurassic boundary, early contineutal plate subduction led to formation of syn-collisional granites(200 Ma). Whereas,late post-orogenic extention resulted in intrusion of A-type granites (75~138 Ma), which was accompanied by development of convergent magma-fluid ore-forming system under an extensional regime and formation of skarn-type tin deposits and fault-controlled hydrothermal Ag-polymetallic deposits. Strong lithospherical shearing and thrusting resulted from Yangtz continental plate subduction caused develorment of a convergent fluid system under a compressional-shearing environment and formation shearing-type Au deposit in the Garze-Litang ophiolitic melange zone. The effect of the Indian-Asian continental collision on the Yidun arc zone was mainly manifested in intra-continental strike-sliding process and alkaline grainte and porphyry intrusion (50~30 Ma). The latter brought us porphyry Au deposits.

关 键 词：岛弧 造山带 成矿系统 岩浆活动 义敦 三江地区 

分 类 号：P542.2[天文地球—构造地质学] P611[天文地球—地质学]