摘要
近年来西藏地质找矿工作取得了重大突破,多不杂铜矿床的发现使得多龙矿集区在地质界里家喻户晓。前人对该矿床的成矿流体做了大量的研究工作,但在成矿流体来源认识上存在着三种不同的看法,这也从侧面反映了多不杂铜矿床的成矿作用具有复杂性。稀有气体同位素长期以来多用于示踪陨石成因、大洋岩石圈地幔演化等方面的研究,成矿热液中的碳、氢、氧同位素组成及变化特征常用于分析流体性质及来源等。在此基础上,本次研究补充分析了成矿流体的氦氩同位素组成和碳氢氧同位素组成,指出了前人在多不杂铜矿床成因机制认识中存在的问题,解释了含矿母岩具有壳幔混染特征的原因,并认为该矿床的成矿流体主要来源于地幔,成矿动力主要来自深部地质过程,矿床的形成与地幔流体作用有关。
In recent years,Tibet geological prospecting work has made a major breakthrough; Duobuza copper deposit was found. There are three different views on the origin of the ore-forming fluid,which also reflects the complexity of Duobuza copper deposit. Noble gas isotope has long been used for studiese on tracing meteorite, oceanic lithosphere mantle evolution and so on; composition and variation of carbon,hydrogen,oxygen isotope characteristics of ore-forming fluids are commonly used in the analysis of fluid properties and sources. On this basis,study on helium and argon isotopic composition and carbon isotopic composition of ore forming fluid was conducted in this paper. The formation mechanism of deposit was pointed out. The reasons for the characteristics of the mixed dye of the parent rocks with the crust and mantle were also explained. It is believed that ore-forming fluid of the deposit is mainly derived from the mantle,and the main source of the ore-forming fluid comes fromdeep geological processes. The formation of the deposit is related to the mantle fluid.