新疆富蕴希力库都克地区岩浆混合作用及其成矿意义  

Magma Mixing in the Xilikuduke Area,Fuyun County,Xinjiang and Its Mineralization Significance

作　　者：王玉往[1] 王京彬[2] 王书来[2] 王莉娟[2] 丁汝福[2] 蒲克信[2] 

机构地区：[1]中国地质大学(北京)地球科学与资源学院中国地质大学地质过程与矿产资源国家重点实验室,北京100083 [2]北京矿产地质研究院,北京100012

出　　处：《地质学报》2008年第2期221-233,I0005,I0006,共15页Acta Geologica Sinica

基　　金：国家重点基础研究发展计划“973”项目(编号2007CB411304和2001CB409806);中国地质大学地质过程与矿产资源国家重点实验室开放课题(编号GPMR0523)联合资助成果

摘　　要：新疆北部希力库都克地区为一斑岩型铜钼金矿区,含矿的花岗闪长岩体中广泛发育4种暗色岩微粒包体:似隐晶状安山玄武岩、细粒闪长岩、少斑状安山(玢)岩和安山玢岩,矿区还产有安山玢岩、英安斑岩、正长岩等脉岩。花岗闪长岩及其包体的岩相学、矿物化学和岩石地球化学特征表明该区发生了岩浆混合作用,其中酸性的花岗闪长质与基性的闪长质岩浆混合,形成了过渡相岩石——安山玢岩质岩浆混合岩。本区矿化与暗色微粒包体有关:矿化较好的地段暗色微粒包体较多,有些包体中磁铁矿微粒普遍发育,有时甚至含少量黄铁矿和黄铜矿等硫化物。研究发现,本区岩浆混合岩——安山玢岩,与蚀变矿化的花岗闪长岩虽然在野外产状和岩石结构上截然有别,但二者的化学成分相当接近:在哈克图上二者的投影点靠近;稀土元素和微量元素上,标准化曲线型式相似(或相同),表明二者具有相似的成因,换言之,岩浆混合作用可能伴随了热液蚀变和矿化的发生。推测本区岩浆混合作用可能是幔源基性岩浆与陆壳花岗质岩浆的混合,由此产生的中酸性岩浆经过分异和流体作用造就了本区的铜钼金矿化。The Xilikuduke area in northern Xinjiang is a porphyry copper-molybdenum-gold deposit. Ore-hosted granodiorite in the area commonly contains four types of melanocratic microgranular enclaves （MME） such as aphanitic andesite-basalt, granule diorite, porphyritic andesite and andesitic porphyrite. There still occur some dykes like andesitic porphyrite, dacitic andesitic porphyry and syenite in the ore district. Lithology, mineral chemistry and lithogeochemistry of granodiorite and its enclaves indicate that there exists magma mixing in this area and that mixing between acid granodiorite magma and basic diorite magma has produced transitional facies-andesitic porphyrite magmatic mixed rock. Mineralization is related to MME, which is supported by following evidence, the more intensive mineralization, the more number of MME~ magnetite, and even pyrite and chalcopyrite commonly exists in some enclaves. Lithogeochemistry reveals that the magmatic mixed rock, i.e. andesitic porphyrite, shares similar geochemistry with alteredmineralized granodiorite, e.g. close plot area on the Harker diagram and similar REE and trace elements patterns in chondrite- and primitive mantle-normalized diagrams, which suggests that the two rocks might have similar genesis. In other words, the hydrothermal alteration and mineralization possibly accompanied with magma mixing. It is deduced that the magma mixing in this area may result from the mixing of mantle-source mafic magma and continental-source granitoid magma, and that the Cu-Au mineralization in this area may be derived from the magmatic differentiation and magmatic hydrothermalism of the intermediate to acid mixed magma.

关 键 词：岩浆混合 暗色微粒包体 岩浆混合岩 矿化 希力库都克 

分 类 号：P611[天文地球—矿床学]