内蒙古额仁陶勒盖花岗岩成因与银矿床的形成

对额仁陶勒盖花岗岩的地质学、地球化学的研究表明，它为岩浆成因，是壳幔混合源岩浆演化的产物；岩体在成岩过程中发生了强烈的结晶分异作用，导致岩浆后期及期后热液中银的富集，银矿床与石英斑岩（花岗岩结晶分异的产物）在地质及地球化学诸多方面存在着显著的成因联系。

内蒙古额仁陶勒盖银矿床成岩成矿模式

地质、地球化学研究表明 :额仁陶勒盖银矿床是次火山热液作用产物。燕山晚期本区受太平洋板块边缘的影响 ,在已存断裂复活的条件下 ,产生壳幔混合作用形成花岗质岩浆 ,该岩浆在地下浅处发生强烈的结晶分异作用形成花岗岩和石英斑岩 ,两者是同一岩浆不同成岩阶段的产物 ,石英斑岩是成岩阶段的最后产物 ,分异作用导致银在成岩后期及期后成矿热液中富集。矿床地质地球化学证据表明石英斑岩是矿床的直接母岩。地表大气水对成矿有下列作用 :(1)有助于发生基底岩石的部分熔融 ;(2 )有利于形成大量的矿液。

Erentaolegai silver deposit in Inner Mongolia as an example of epithermal deposit

1 Comparison with the characteristics of geology and geochemistry of typical epithermal silverdeposit Erentaolegai silver deposit is located to the west bank of Kelulun river in the Xibarhuyou Banner,south-west of Manzhouli. The geotectonic is the joint of Hailar basin and Manzhouli-Xinbarhuyou Banner’svolcanic mole track. The stratas in the mining area are upper Jurassic Tamolangou formation andShangkuli formation: the former consists of andesite mainly and the latter is divided into three parts fromtop to bottom, namely rhyolite, decite, trachyte. The types of igeous rock in the mining area are graniteand quartz porphyry, both with age (120 ±6) Ma as determined by the Rb-Sr isochron. The principalstructures in the mining areas are faults, trending SN, NW, NE, mainly SN. The ore bodies are controlledby faults. It is a large-scale silver deposit found recently. Many years’ research shows that it is a silverepithermal deposit. Table 1 lists a comparison with the typical silver epithermal deposits.