摘要
在“三江”地区,“黑矿型”块状硫化物矿床和矿点均分布于义敦岛弧带上。该岛弧具典型的沟—弧—盆体系,在垂直岛弧方向上自东而西可分为4个带:甘孜—理塘缝合带(古海沟);雀儿山—稻城弧前区(弧—沟间断);赠科—乡城火山弧区;勉戈—热达弧后区。研究表明,义敦岛弧是一个建筑于从扬子准地台边缘分裂出来的大陆裂谷堑垒体系的基础上,经历了压张交替、升降更迭的复杂历史的张性火山岛弧,是由于甘孜—理塘微板块在晚三叠世诺利克期向西陡深俯冲形成的。在其发展历史中出现岛弧裂谷阶段和相伴的“双峰式”火山活动是该岛弧最重要的特点,为“黑矿型”块状硫化物矿床的成矿造就了有利的构造—火山条件。
Yidun Triassic volcanic island-arc is located between Jinshajiang fracture zone and Ganzi Litang fracture zone, within which all volcanogenic massive sulphide (VMS) deposits and occurrences discovered so far in SanJiang Area distribute. It consists of two large volcano-sedimentary basins, Baiyu basin and Xiangcheng basin. Four tectonic units have been seen from east to west across the island-arc. Ganzi-Litang suture zone (ancient trench) , forearc, volcanic arc and backarc basin.It has been suggested that Yidun Island-Arc was a tensional volcanic island-arc, which had a complicate history of alternate compression and tension and developed upon the base of continental rifting system. It formed in the Norian stage of Late Triassic presumably as a result of the westward subduction of Ganzi-Litang microplate. The intrarc-rifting and associated bimodal volcanism are the most important characteristics of Yidun Island-Arc and they provide a favourable volca-notectonic setting for the formation of Kuroko-type VMS deposits.
出处
《地球科学（中国地质大学学报）》
EI
CAS
CSCD
北大核心
1991年第2期153-164,共12页
Earth Science-Journal of China University of Geosciences
关键词
岛弧
形成
演化
硫化物
矿床
Yidun Island-Arc, VMS, Sanjiang Area.
