新疆东准拉伊克勒克斑岩铜(钼)矿床的黄铁矿成分标型及硫同位素特征

Composition and Sulfur Isotope Characteristics of Pyrite from the Layikeleke Porphyry Cu(Mo) Deposit, from East Junggar,Xinjiang

摘要: 拉伊克勒克斑岩矿床是近年应用现代综合地球物理勘查方法，在第四系覆盖区新发现的隐伏斑岩铜(钼)矿床，其赋矿岩体为英云闪长岩，铜(钼)成矿作用与岩体的钾化–绢云母化–绢英岩化–硅化极为密切，并以浸染–细脉浸染形式产出。矿床主要成矿元素为Cu、Mo、Pb、Zn、Au、Ag等，主要以黄铁矿、黄铜矿、辉钼矿、方铅矿、闪锌矿等硫化物产出。黄铁矿不仅是各成矿阶段的贯通性矿物，更是指示铜钼矿化的标型矿物，其电子探针(EPMA)数据显示，化学成分主要表现为铁亏损型，黄铁矿中ω(Co)含量介于0.011%~0.179%，Co/Ni比高，说明黄铁矿是在中–高温条件下形成的，ω(Se)约为n × 10⁻⁴，S/Se比值为23~1200，表明矿区黄铁矿的形成与火山作用–岩浆热液有关；7件黄铁矿、2件辉钼矿和1件黄铜矿δ³⁴S值介于−2.2‰~0.0‰之间，变化范围窄，极差小，具有地幔硫的特征，其双峰特征表明在成矿作用过程中有大气水的参与。以上特征表明，拉伊克勒克斑岩矿床成矿物质来源于深部地幔，Cu、Mo元素是在岩浆热液作用下沉淀成矿的。

Abstract: The Layikeleke deposit is an insidious porphyry deposit newly discovered by some comprehen-sive geophysical exploration in quaternary coverage area. The ore-bearing rock tonalite, which possess potassic alteration, sericitization and silicification, and veinlet-disseminated Cu(Mo) mi-neralization. The main ore-forming elements of the deposits are Cu, Mo, Pb, Zn, Au, Ag, etc., and are mainly produced from sulfides such as pyrite, chalcopyrite, molybdenite, galenite and sphalerite. Pyrite is not only the transfixion mineral in each mineralization stage，but also topomorphic indicates Cu(Mo) mineralization. EPMA electronic probe data display that iron deficiency type pyrite is dominated. The ω(Co) content in pyrite is between 0.011% and 0.179%, and the Co/Ni ratio is high, indicating that pyrite is formed under medium-high temperature conditions. The Se is about n × 10⁻⁴ and the S/Se ratio is 23~1200, showing that the formation of pyrite is related to volcanism magmatic hydrothermal. The δ³⁴S values of 7 pyrites, 2 molybdenite and 1 chalcopyrite range from −2.2‰ to 0.0‰, with a narrow range of variation. The sulfur comes mainly from the deep mantle. The characteristics of bimodal distribution show that atmospheric water is involved in the process of mineralization. The above characteristics indicate that metallogenic material are derived from deep mantle, and Cu and Mo elements are precipitated and formed under the action of magmatic hydrothermal fluids.