内蒙古查干德尔斯钼矿成矿期花岗岩地球化学特征及成岩背景

查干德尔斯钼矿床位于中蒙边界西段宝音图隆起,是近年勘查发现的一处大型隐伏矿床。辉钼矿化常见于晚二叠世花岗质岩体中,多呈浸染状、网脉状分布,具斑岩型矿床特征。通过对成矿期查干德尔斯岩体——似斑状黑云母二长花岗岩开展系统的元素地球化学分析研究,进而探讨其成岩背景。结果表明:查干德尔斯岩体具有高硅、高碱、过铝质和高钾钙碱性特征。通过微量元素地球化学研究,认为查干德尔斯岩体的原岩受到早期陆缘弧俯冲作用,进而部分熔融,岩浆上侵到浅部地壳后与下元古界宝音图群发生混染,并且伴随成矿物质的富集沉淀。Nb-Y和Rb-(Y+Nb)构造环境判别图解显示,德尔斯岩体形成演化的构造背景为晚古生代末期的后碰撞环境。

Metallogenic granite Geochemical characteristics and diagenetic background of the Chagandeersi Molybdenum Deposit, Inner Mongolia

Chagandeles molybdenum deposit is located in Baoyintu uplift in the western part of the Sino Mongolian border. It is a large-scale concealed deposit discovered in recent years. Molybdenite mineralization is common in the Late Permian granites, which are disseminated, stockwork, and have the characteristics of porphyry deposits. The ore-forming granite is porphyritic biotite monzogranite. The element geochemistry shows that the granite is characterized by high silicon, high alkali, peraluminous and high potassium calc alkaline. The source rocks were subducted by the early continental margin arc and then partially melted. The magma intruded into the shallow crust and then mixed with the Baoyintu group of Lower Proterozoic. The tectonic setting for the formation and evolution of the dersi pluton is a post collisional environment at the end of Late Paleozoic.