西准噶尔托里县布尔克斯台岩体岩浆混合作用的地球化学特征及其成矿意义

西准噶尔托里县阿达依金矿所在的布尔克斯台岩体主要由寄主岩石、闪长质微细粒包体和中性岩墙组成。为判别岩浆的化学混合及岩浆混合作用与金、铜成矿作用的关系,对布尔克斯台岩体地球化学成分的相关度和寄主岩石的金、铜含矿性进行了研究。寄主岩石、闪长质微细粒包体和中性岩墙的稀土元素配分曲线和微量元素蛛网图形态相似,在岩石硅酸盐成分哈克图解、同分母氧化物比值相关图解、微量元素相关图解和同分母比值相关图解上均呈现直线状趋势,表明岩浆混合作用过程中发生了显著的元素迁移和成分交换。寄主岩石金、铜含量均较高且分布规律相似,在闪长质微细粒包体相对富集区域异常强烈,表明以闪长质微细粒包体为代表的幔源基性端员可能为阿达依金矿的形成提供了金、铜成矿物质来源。布尔克斯台岩体壳幔岩浆混合作用与金、铜成矿作用的相关关系,表明幔源的基性端员对成矿作用的贡献可能是达尔布特构造-岩浆带金、铜富集的主要原因之一。

Geochemical characteristics and ore-forming significance of magma mixing action of Buerkesitai granite in Tuoli County, Western Junggar

The Buerkesitai granite where the Adayi gold ore deposit occurs is composed of host rocks, diorite microgranular enclaves and intermediate dyke swarms. The relative composition of geochemistry is one of the most effective means for determining the mixture of magma, whereas the concentrations of gold and copper geochemical prospecting samples from different areas of the host rock can identify the relationship between gold and copper ore potential and the mixture of magma. The patterns of REE and trace elements are similar to those of the host rock, diorite microgranular enclaves and intermediate dyke swarms. Harker diagrams, ratio diagrams in the same denominator, correlation diagrams and ratio diagrams of trace elements in the same denominator of the host rock, diorite microgranular enclaves and intermediate dyke swarms all have the same linear trends, which means that significant element migration and transfer of component once occurred. The host rock has high gold and copper concentrations and their regularities of distribution are similar. The fact that the gold and copper anomalies are scattered around areas where abundant diorite microgranular enclaves exist indicates that the mantle-sourced basic end-member represented by diorite microgranular enclaves might have provided the material source for gold and copper mineralization. The association between gold and copper mineralization potential and magma mixture indicates that one of the most important reasons for the enrichment of gold and copper in Darbut tectonic-magmatic belt is the contribution of the mantle-sourced basic end-member to metallogenesis.