新疆西天山菁布拉克含铜镍硫化物杂岩体及恰干撒依铂矿点岩石成因研究

A large number of nickel-copper magmatic sulfide deposit relative to mafic-ultramafic rocks has been found in the north of Xinjiang, which of the formation era was between 285Ma and 270Ma. Pyroxene diorite which relative to mineralization in Jingbulake mafic-ultramafic rocks in the western Tianshan Mountain formatted at 434.4±6.2Ma. Jingbulake mafic-ultramafic rocks has been the ideal region for the research on copper-nickel mineralization at early Paleozoic in Xinjiang. Recent years, the gabbro, in Qiagansayi mafic-ultramafic rock nearby Jingbulake, has a SHRIMP zircon U-Pb isotope age of 407.9±4.5Ma. The research study on the mafic-ultramafic rocks in Jingbulake and Qiagansayi. Through the characteristic of facies and mineralogy, the analysis of geochemical and PGE, we can calculate the composition of parental magma, discuss the magmatic differentiation and crustal contamination, reveal the liquation and the mechanism of formation in the nickel-copper magmatic sulfide deposit. This study can not only enrich the theory of mineralization on the nickel-copper magmatic sulfide deposits, also support the breakthrough of nickel and copper prospecting in Xinjiang province.

新疆北部发育大量岩浆铜镍硫化物矿床，其形成时代多集中在285-270Ma，西天山菁布拉克与铜镍成矿有关的辉石闪长岩形成于434.4±6.2Ma，是研究新疆北部早古生代镁铁-超镁铁岩形成演化及铜镍成矿的理想地区。近年，申请者在菁布拉克邻区恰干撒依铂矿点进行了锆石SHRIMP 定年研究，获得辉长岩的年龄为407.9±4.5Ma。本项目以菁布拉克矿床含矿岩体和恰干撒依铂矿化岩体为主要研究对象，通过岩相学及矿物学（橄榄石、辉石、斜长石等矿物的晶体化学）、岩石地球化学和同位素研究、各岩石类型及矿石类型的铂族元素分析，计算母岩浆成分，探讨分离结晶作用、同化混染程度和硫化物熔离时限和成岩成矿作用过程，为新疆铜镍找矿突破提供技术支撑。

新疆发育大量与镁铁-超镁铁岩有关的铜镍硫化物矿床，形成时代集中在285~270Ma，最新研究揭示西天山菁不拉克与铜镍成矿有关的辉石闪长岩形成于434.4±6.2Ma，是研究新疆早古生代镁铁-超镁铁岩形成演化及铜镍成矿的理想地区。而铂族元素作为岩浆铜镍硫化物矿床硫化物熔离作用最敏感的示踪剂，在示踪镁铁-超镁铁岩岩浆源区性质、研究岩浆演化及铜镍成矿作用方面具有重要意义。本项目以菁不拉克不同岩相的含PGE岩体为研究对象，通过PGE示踪对比研究，结合其他相容元素和不相容元素分析，总结幔源岩浆起源及演化过程中Cu 、Ni和PGE 的变化规律，探索是否发生了硫化物熔离以及硫化物熔离机制，进一步约束矿床成因。该研究不仅可以丰富岩浆铜镍硫化物矿床成矿理论，而且对于新疆铜镍找矿突破提供机制支撑。