西天山巨型金铜铅锌成矿带构造成矿演化和找矿方向

Tectonic-Metallogenic Evolution of Western Tianshan Giant Au-Cu-Zn-Pb Metallogenic Belt and Prospecting Orietation

西天山产有Muruntau、Kumtor、Kalmakyr等巨型金矿床和Kalmakyr、Dal′neye等世界级铜矿床以及Tekeli等超大型铅锌矿床,构成世人瞩目的巨型金铜铅锌成矿带。新疆西天山金、铜、铅锌矿找矿面临重大突破,不断认识乌兹别克斯坦—吉尔吉斯斯坦—哈萨克斯坦东南部—中国新疆西部整个西天山的构造成矿过程,明确新疆西天山金、铜、铅锌矿重大找矿突破方向,预测大型矿集区十分必要。本文通过境内外野外地质矿产广泛调研和对相关文献综合研究,认为西天山造山带形成演化经历前寒武纪古陆边缘裂陷盆地、古生代洋-陆俯冲增生、晚古生代陆-陆碰撞造山、中—新生代坳陷盆地四个主要地质过程,造就出四类重要成矿系统和类型:1元古宙边缘裂陷盆地铅锌成矿系统SEDEX型;2古生代俯冲岛弧金铜铅锌成矿系统斑岩-矽卡岩-浅成低温热液型;3晚古生代碰撞造山金铅锌成矿系统造山型-MVT;4中—新生代坳陷盆地铅锌铜成矿系统砂岩型。综合对比西天山境内外成矿系统地质发育特点,预测新疆西天山那拉提-额尔宾中天山隆起带是造山型金矿找矿重大突破区,吐拉苏盆地和巴音布鲁克中天山以及那拉提山北坡有望实现斑岩型金铜找矿突破,伊犁地块南缘元古宇SEDEX型铅锌找矿值得关注,山间/山前盆地无疑是砂岩型铅锌铜找矿优先选择。

There are giant gold deposits such as Muruntau,Kumtor and Kalmakyr,world-class copper deposits such as Kalmakyr and Dal＇neye,and super-large zinc-lead deposits such as Tekeli in western Tianshan forming a giant Au-Cu-Zn-Pb metallogenic belt,attracting the attention from the world.Yet it is hoped to find gold,copper and zinc-lead deposits significantly in Xinjiang western Tianshan,China.It is necessary to continuously understand the tectonic-metallogenic processes of total western Tianshan from Uzbekistan,Kylgyzstan,through south-eastern Kazakhstan to western Xinjiang,China,confirm the survey direction and predicte large ore clusters in western Tianshan.Through a wide survey of regional geology and ore deposits in western Tianshan and synthetic study of references,we suggest that the western Tianshan orogenic belt experienced four geological processes,they were Precambrian continent marginal basin,Paleozoic ocean-continent subduction accretion,Later Paleozoic continent-continent collision orogeny and Mesozoic-Cenozoic depression basin.Accordingly,there were forming four metallogenic systems and types of..①Proterozoic marginal basin Zn-Pb system and SEDEX-type,②Paleozoic subduction arc Au-Cu-Zn-Pb system and porphyry-,skarn-,and epithermal-types,③Later Paleozoic collision orogenic Au-Zn-Pb system and orogenic-tpye and MVT,④ Mesozoic-Cenozoic depression Zn-Pb-Cu system and sandstonetype.Based on the synthetic comparission of the metallogenic systems developing in western Tianshan at home and abroad,it is predicted that Nalati-Enlbin centre Tianshan rise zone is very important to find orogenic gold deposits,the Tulasu basin,Bayinbuluk centre Tianshan and northern margin of Nalati are hoped to find porphyry gold-copper deposits,the new SEDEX-type of zinc and lead deposits would be find in Proterozoic systems in southern margin of Yili block,and the Mesozoic-Cenozoic depression basin in or in front of western Tianshan is certainly the first choice to find the sandstone-type of Zn-Pb-Cu deposits.