新疆萨瓦亚尔顿金锑矿床成矿作用同位素地质年代学

Metallogenic Chronology of the Sawayaerdun Gold-Antimony Deposit in Xinjiang

萨瓦亚尔顿金锑矿床形成的时代和成矿期次一直存在较大争议。成矿作用同位素地质年代学研究表明 ,多金属硫化物和少金属硫化物含金石英脉矿物流体包裹体Rb Sr等时线年龄分别为 342± 2 7Ma和 2 4 6± 16Ma ,表明萨瓦亚尔顿金锑矿成矿作用至少有 2期 :第 1期发生在石炭纪 ,第 2期发生在晚二叠世—早三叠世 ;矿区出露的二长斑岩脉单颗粒锆石U Pb年龄为133.7～ 131.0Ma,表明岩浆侵位时间发生在晚侏罗世—早白垩世 。

The ore-forming ages and phases of the Sawayaerdun gold-antimony deposit constitute a problem of long controversy. Isotopic geochronological study of the ore-forming process shows that fluid inclusion Rb-Sr isochron ages for gold- and polymetallic sulfides-bearing quartz veins and gold-bearing quartz veins with small quantities of sulfides are 342±27 Ma and 246±16 Ma,respectively,which indicate that mineralization of gold in this orefield experienced at least two epochs,namely Carboniferous and Late Permian-Early Triassic. The single zircon U-Pb age of 133.7～131.0 Ma for monzonite-porphyry in the orefield implies that the magma was intruded after the ore-forming process in Late Jurassic to Early Cretaceous.