摘要
新疆阿尔泰南缘晚古生代火山岩区分布着多个金属成矿带,其中以阿舍勒成矿带和可可塔勒成矿带最为著名,矿床地质研究表明,产于早—中泥盆统的多金属硫化物矿床大多具有VMS型矿床的特征。通过测定部分典型矿床的Sr-Nd-Ph同位素组成,发现从乔夏哈拉至可可塔勒矿区初始锶逐渐升高,由0．704407到0．714485；而ε_Nd(t)由正值变为负值。反映成矿物质来源以幔源为主,过渡到壳源物质的混入逐渐增加。从Pb同位素特征来看,成矿带内的大多数矿床具有火山岛弧区成矿的特征,矿石铅同位素组成显示正常铅,但可可塔勒铅锌矿床矿石铅具有放射性成因铅的加入。结合成矿带内各主要块状硫化物矿床的地质和地球化学特征,本文认为阿舍勒铜锌矿可能产于与俯冲有关的弧内(弧间)盆地环境,可可塔勒铅锌矿、蒙库铁(铜)矿和铁木尔特铜铅锌矿产于弧后盆地环境。而乔夏哈拉铜铁矿Sr-Nd-Pb同位素组成显示其具有MORB特征,这与其“塞浦路斯型”块状硫化物矿床的特征相吻合。
There are several pnlymetallic metallogenic belts within the Paleozoic volcanic rock belt on the Southern margin of Altaid, in which both Asbele and Keketale belt are the most famous. It is found that most deposits hosted by early-middle Devonian volcanic rock are the VMS type. Some rules are identified after we carried out isotope studies on some representative deposits. The values of initial Sr increase gradually from Qiaoxiahala to Keketale （0. 704407 to 0. 714485） , and the εNa （t） values change from positive to negative coincidentally. It means that the origin of ore-forming material is mainly from the mantle. All of the selected deposits have the characteristics of island arc except Qiaoxiahala （ MORB type） based on the Pb isotope data. In the meanwhile most of Pb isotopic data are the normal Pb except the Keketale deposit that it may be mixed by radiogenic lead. Therefore, we conclude that the ore-forming material mainly comes from mantle, and there is more and more crustal material getting mixed in from south to north. Finally, we provide a supposed metallogenic model based on the geochemical and geologic characteristics： Qiaoxiahala copper-iron-gold deposit should form in a MORB setting, Ashele copper-zinc deposit may locate in an inner-island are basin; Timuerte copper-lead-zinc deposit, Mengku iron （copper） deposit and Keketala lead-zinc deposit maybe form in the back-arc basin.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2006年第1期145-152,共8页
Acta Petrologica Sinica
基金
国家重点基础研究计划项目(2001CB409805)
国家自然科学基金(40473028)资助.
