摘要
新疆西天山吐拉苏金矿集区产有阿希、京希-伊尔曼得等大型浅成低温热液型金矿,这里是否具备类似西南太平洋岛弧区在浅成低温热液型金矿深边部寻找斑岩型铜金矿地质条件？笔者针对吐拉苏金矿集区北部原＂恰尔巴赫特＂伴有铜矿化的岩株开展地质剖面实测、地质填图、岩相学、元素地球化学和年代学研究,引导商业勘查,发现原＂恰尔巴赫特＂岩株实际上是由成群产出的辉石闪长岩、闪长岩、石英闪长岩、花岗闪长岩和闪长玢岩等小岩体组成的克峡希＂小岩体群＂,其中部分小岩体中已发现斑岩型工业铜矿体。小岩体群中不同侵入体均属钙碱性系列,弧岩浆性质明显,彼此之间微量元素组成近一致且与本地区同时代火山岩微量元素组成相似,同属北天山洋向南向伊犁板块之下俯冲岛弧环境中同源岩浆晚泥盆世—早石炭世喷出-侵入的统一岩浆序列。在大约10 Ma期间,克峡希地区发生了4~5次同源岩浆侵入,依次形成辉石闪长岩（（357.2±3.0）Ma）、石英闪长岩（（356.4±2.2）Ma）、花岗闪长岩（（350.8±3.8）Ma）、闪长玢岩（（348.0±2.2）Ma）,它们与吐拉苏地区下石炭统火山岩同时代。西天山吐拉苏地区浅成低温热液金矿集区具备斑岩铜金成矿系统发生发展的有利地质条件,有望实现斑岩铜矿找矿重大突破。
The Tulasu gold mineral concentration district in western Tianshan of Xinjiang developed large epithermal gold deposits of A＇xi and Jingxi-Yelmand.Is it possible to discover the porphyry Cu-Au deposit beneath or adjacent to the epithermal Au deposits just like that in the southwestern Pacific island-arc environment？In order to find out the Cu-Au deposit,we surveyed the geology of the former Qiarbahete stock with copper occurrence in the north of Tulasu,researched its petrography,element geochemistry and geochronology and guided the commercial exploration.The works revealed that the stock is a cluster of small intrusions including pyroxene diorite,diorite,quartz diorite,granodiorite,dioritic porphyrite and can be grouped as＂Kexiaxi cluster＂.Porphyry-style industrial copper mineralization has been discovered in some of the small intrusions.The small intrusions are calc-alkline with apparent arc magma characteristics,the trace element compositions of these intrusions are consistent and similar to those of the contemporaneous volcanic rocks in the Tulasu district,and they belong to the same eruption-intrusion magmatic sequence of the late Devonian to the early Carboniferous under the setting of southward subduction of northern Tianshan Ocean to the Yili plate.During about 10 million years,there were four or five episodes of synchronous magma intrusion,i.e.,pyroxene diorite（357.2±3.0Ma）,quartz diorite（356.4±2.2Ma）,granodiorite（350.8±3.8Ma）,and dioritic porphyrite（350.8±3.8Ma）in the Kexiaxi cluster,and they are contemporaneous with Lower Carboniferous volcanic rocks in the Tulasu district.Therefore it is geologically favorable that the porphyry-style Cu-Au mineral deposits may be found beneath or adjacent to the epithermal Au deposits in the Tulasu gold mineral concentration district,western Tianshan of Xinjiang.It is hopeful to have important breakthrough in the prospecting of large porphyry-style Cu-Au deposits in the Tulasu district.
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2013年第6期180-194,共15页
Earth Science Frontiers
基金
国家科技支撑计划项目(2011BAB06B02)
中国地质调查工作项目(1212011085069
121211220926)
关键词
小岩体群
岩浆过程
斑岩Cu-Au系统
克峡希
吐拉苏金矿集区
新疆西天山
a cluster of small intrusions
magmatic processes
porphyry Cu-Au system
Kexiaxi
Tulasu district
western Tianshan of Xinjiang
