尕尔穷—嘎拉勒铜金矿集区S、Pb同位素地球化学特征

以西藏尕尔穷—嘠拉勒铜金矿集区为研究对象,通过分析矿石硫化物S、Pb同位素组成特征,探讨了矿床物质来源,结果表明:1矿石金属硫化物δ34S值为-4.4‰~6.2‰,平均为0.13‰,主要集中于-2‰~1.5‰,具塔式分布特征,总体体现出地幔岩浆硫特点,但已受到少数地壳硫的混染;2矿石Pb同位素组成范围较大,体现出混源铅特征,其μ值特征及构造环境判别图显示区内铅起源于幔源,主要为地幔与上地壳混合的造山带铅;3与多龙矿集区多不杂与拿若矿床对比研究发现,两矿集区硫源均为岩浆硫,处于俯冲背景下的多龙矿集区成矿物质来源相对较深,而处于碰撞环境中的尕尔穷—嘎拉勒成矿物质来源相对较浅。上述分析成果对于区内找矿工作具有一定的参考价值。

S,Pb Isotope Geochemical Characteristics of the Gaerqiong-Galale Gold-Copper Ore-concentrated Area

Taking the Gaerqiong-Glalae Cu-Au ore-concentrated area as the research object，the S and Pb isotope compositions characteristics of sulfide ore and the metallogenic material sources are analyzed.The results show that:①the δ34S value of the ore metal sulfides vary from -4.4‰ to 6.2‰，with the average δ34S value of 0.13‰，mainly between -2 ‰ and 1.5 ‰，and with the characteristics of tower distribution,it overall reflects the characteristics of mantle magma sulfur，but has been contaminated by a few of crustal sulfur;②the composition range of Pb isotope of the ore is large，showing the characteristics of mixed source of lead,the characteristics of μ value and tectonic environment discrimination diagram indicate that lead of the research region is originated in the mantle source region，mainly the upper crust and mantle mixed orogenic belt lead;③comparing with the Buza and Naruo deposit in Duolong ore-concentrated area and the Gaerqiong-Glalae Cu-Au ore-concentrated area，it is considered that the source of sulfur of the above ore-concentrated areas are both magmatic sulfur，and the ore-forming materials of Duolong ore-concentrated area is relatively deep with the environment of subduction，and the ore-forming materials of Gaerqiong-Galale ore-concentrated area is relatively shallow with the environment of collision.The above analysis results have a certain reference for the prospecting work in the research area.