东昆仑夏日哈木铜镍硫化物矿床辉石特征及地质意义

夏日哈木铜镍硫化物矿床的发现在矿床规模、成矿时代及成矿区带方面都有重要意义。辉石作为最主要的造岩矿物之一,广泛赋存于该矿床的各岩相中,在橄榄岩相中多为填隙相,而在辉石岩相及辉长岩相中多呈堆晶相;总体上,斜方辉石含量大于单斜辉石含量。辉石Cr_2O_3含量在橄榄岩相、辉石岩相、辉长岩相具有依次降低的趋势,说明从早到晚含矿的橄榄岩相、辉石岩相、辉长岩相先后结晶,并非所有辉长岩相的结晶均早于橄榄岩相和辉石岩相;单斜辉石SiO_2、TiO_2及Na_2O含量之间的关系显示夏日哈木矿床母岩浆属拉斑玄武质岩浆,较高的Al_2O_3含量(2.55%~10.61%)暗示岩体形成过程中与富铝围岩发生了同化混染作用。

Mineral?Characteristic? and?geological?significance of?pyroxene?from Xiarihamu Ni-Cu sulfide deposit in the Eastern Kunlun orogenic belt,?Northwestern China

The discovery of the Xiarihamu Ni-Cu Sulfide deposit is of great significance in the deposit scale, metallogenic age and metallogenic belt. Pyroxene is one of the most important rock-forming minerals, which is widely present in all rock types of the deposit, This rock is mostly interstitial in peridotite, and cumulus crystal in pyroxenite and gabbro. Overall, the content of orthopyroxene is larger than that of clinopyroxene in the intrusion. Cr2O3 content of pyroxene in peridotite, pyroxenite and gabbro has a decreasing trend, indicating that the ore-bearing peridotite, pyroxite and gabbro crystallized successively from early to late, while not all gabbro crystallized earlier than peridotite and pyroxenite. The relationships among the SiO2, TiO2 and Na2O contents of clinopyroxene show that the parental magma of Xiarihamu could be a tholeiitic magma. A higher Al2O3 content of clinopyroxene (2.55% ~ 10.61%) implies that the intrusion was contaminated by aluminous surrounding rocks during the generation of the intrusion.