天山巴音布鲁克地区金锑矿床成矿作用同位素年代学研究

Isotopic Chronology of Gold-Antimony Deposits in Bayinbuluke Area of the Tianshan Mountains

近年来 ,在天山中段巴音布鲁克地区发现了一系列金锑矿床 ,代表性矿床有大山口金矿和查汉萨拉锑矿。成矿作用同位素地质年代学研究表明 ,大山口金矿区含金黄铁矿 石英脉和含金黄铁矿 褐铁矿 石英脉的石英流体包裹体Rb Sr等时线年龄分别为 35 4± 8.1Ma(2σ)和 344± 2 1Ma(2σ) ,二者在实验测定误差范围内一致 ,代表大山口金矿形成的时间发生于早石炭世 ,成矿作用与区域韧性剪切作用有关 ;查汉萨拉锑矿床石英 辉锑矿脉和石英 黝铜矿 辉铋矿 辉锑矿脉石英流体包裹体Rb Sr等时线年龄为 2 5 7± 2 3Ma(2σ) ,表明该矿床形成于海西晚期 印支早期 ,成矿作用与陆内构造变形作用有关。

Several gold-antimony deposits,such as the Dashankou gold deposit and the Chahansala antimony deposit,have recently been discovered in Bayinbuluke area of the Tianshan Mountains. Isotopic chronological studies of mineralization show that the fluid inclusion Rb-Sr isochron age of gold-bearing pyrite-quartz veins and pyrite-limonite-quartz veins from the Dashankou gold deposit are 354±8.1 Ma(2σ) and 344±21 Ma(2σ),respectively. The two ages are consistent within the test errors,indicating that the gold deposit was formed in early Carboniferous and was related to regional shearing. The fluid inclusion Rb-Sr isochron age of quartz-stibnite veins and quartz-tetrahedrite-bismuthinite-stibnite veins from the Chahansala antimony deposit is 257±23 Ma(2σ),implying that the deposit was formed during late Hercynian-early Indosinian and had connection with intracontinental deformation.