摘要
新疆西天山博罗科努成矿带与中酸性侵入岩有关的夕卡岩-斑岩-热液脉型Fe、Cu、Mo、Pb、Zn成矿系统,是在晚古生代北天山洋向南部伊犁板块之下俯冲消减的活动大陆边缘背景下形成的。与成矿相关的中酸性岩体侵位于晚泥盆世—早石炭世,岩石具有高硅、富碱且富钾、准铝质-弱过铝质的Ⅰ型花岗岩特征,其轻稀土和大离子亲石元素富集以及高场强元素亏损,显示俯冲带岛弧岩浆作用的特点。夕卡岩型铁铜矿床主要产于中酸性侵入岩与奥陶系碳酸盐岩的内外接触带,斑岩型铜钼矿床产于中酸性侵入岩体的顶部以及与志留系细碎屑岩的接触带附近,热液脉型铅锌银矿床则产于远离岩体的志留系细碎屑岩的构造破碎带中。矿床同位素地球化学特征表明,成矿物质主要来自岩浆及其所分泌的气水热液,成矿时代与中酸性岩体的成岩时代相近,为晚泥盆世—早石炭世。根据成矿系统形成后的保存和变化情况,认为在3571铜矿区的深部具有斑岩型铜钼成矿的良好潜力。
The skam-porphyry hydrothermal vein type of Fe, Cu, Mo, Pb and Zn mineralization system associated with intermediate to acidic intrusive rocks in the Boluokenu metallogenic belt of the West Tianshan, Xinjiang formed during the southward subduction of the North Tianshan ocean under the Yili plate in the late Paleozoic. The ore-related intermediate to acidic intrusions were emplaced during the late Devonian to the early Carboniferous. The intrusive rocks have high contents of SiO2, K2O and Na2 O are metaluminous to peraluminous, and show geochemical features of I-type granitoids. They are enriched in LREE and large-ion lithophile elements and depleted in high field strength elements, indicating subduction-related arc magmatism. The skam-type Fe-Cu deposits occurred at the contact zones between intrusive rocks and Ordovician carbonates, the porphyry-type of Cu Mo deposits occurred at the uppermost parts of intrusions and their contact zones with Silurian fine-grained clastic rocks, and the vein-type Pb-Zn-Ag deposits are normally distal to intrusions and hosted by fractured zones in Silurian clastic rocks. Isotopic geochemistry indicates that the ore-forming materials were derived from magma and related magmatic hydrothermal fluids. The timing of mineralization is the late Devonian to the early Carboniferous, roughly coincident with that of the intrusive rocks. Based on the analysis of preservation conditions after the formation of the mineralization system, it is suggested that the 3571 Cu deposit should have a good potential for prospecting porphyry Cu-Mo ores at deep sites.
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2014年第5期156-175,共20页
Earth Science Frontiers
基金
国家自然科学基金项目(U1303292)
国家科技支撑计划项目(2011BAB06B02-02)
关键词
多金属成矿系统
构造岩浆演化
夕卡岩型矿床
斑岩型矿床
博罗科努成矿带
西天山
polymetallie mineralization system
tectonomagmatic evolution
skarn deposit
porphyry deposit
Boluokenu metallogenic belt
West Tianshan
作者简介
顾雪祥（1964-），男，教授，博士生导师，主要从事矿床学和地球化学研究。E-mail：xuexiang_gu@cugb．edu．cn
