内蒙古额仁陶勒盖银矿床地球化学研究

额仁陶勒盖银矿床位于内蒙古新巴尔虎右旗境内.燕山晚期本区受太平洋板块的边缘影响，额尔古纳断裂带复活，产生强烈的花岗质岩浆活动.综合岩石的常量元素、微量元素、稀土元素及氧、锶同位素等证据表明花岗质岩浆为壳幔混合作用的产物.由花岗岩体向东依次排列Ⅰ、Ⅱ、Ⅲ和Ⅳ号矿带，其中Ⅱ、Ⅲ为主矿带，上述矿带在矿带规模、矿脉的矿石组成、矿石的结构构造和矿物成分、流体包裹体成分和均一温度等诸方面存在明显的水平分带；同时，各矿带均显示一样的矿石类型的垂向分带，即地表是氧化矿石（次生氧化富集带），向下是石英脉-硅化带，深部是硫化物-蚀变岩型矿石带.不同类型矿石的流体包裹体成分一致，均为H₂O-CO₂-Ca²⁺-Na⁺-K⁺-SO₃^2--Cl^-型成矿流体，说明它们有相同的来源.氧同位素表明，大气水在成岩成矿过程中起重要作用，大气水的作用使矿液量大增.含氧大气水的加入还有以下两方面的作用：（1）可能发生OH^-取代Cl^-，从而使与岩浆平衡的富矿流体及其后形成的成矿热液Cl^-大增，提高了萃取岩浆及围岩中银的能力；（2）导致成矿流体的氧化-还原条件及酸碱度的变化.成矿各阶段形成的石英脉型矿石中的稀土元素、微量元素及氧、氢、硫、铅同位素特征表明，花岗岩、石英斑岩与矿石之间存在着显著的物源上的联系.由于石英斑岩是花岗质岩浆成岩期的最后产物，分异作用导致银在成岩期及期后成矿热液中富集.因此，石英斑岩是矿床的直接母岩.地表大气水在成岩和成矿作用的全过程中起重要作用.

THE GEOCHEMISTRY STUDY OF ERENTAOLEGAI SILVER DEPOSIT IN INNER MONGOLIA

The Erentaolegai silver deposit is located in Xinbaerhuyo County,Inner Mongolia. The local area was edeg subjected to the movement in later Yanshan.The faults which had been exited were revived,bringing about intense activity of granite magma.Miscellaneous geologic investigations on the invariable primary elements,trace elements,rare earth elements and the isotopes of oxygen and stronitum show that the magma was the product of the crust mantle mixture.The magma underwent crystallization differentiation,froming granite and quartz porphyry. From west(rock body)to east,there are four ore belts named Ⅰ,Ⅱ,Ⅲ and Ⅳ arranged successively.The belts had a horizontal zoning in many ways such as the scale of the ore belts,the composition of the ore in the ore veins,ore texture and structure,mineral composition,and the composition of the fluid inclusions.And more,they show the same vertical zoning of ore types,i.e., oxidized ore in the surface,quartz silicated typed ore in deeper and sulfide altered rock ore zone in the deepest.The compositions of inclusions in all kinds of ores are identical, i.e., H 2O CO 2 Ca 2+ Na + K + SO 3 2- Cl -, showing that they come from the same source.Oxygen isotopes show that meteorological water on earth's surface played an important role in forming the magma and deposit:(1) probably occured OH - replacing Cl - made the ore solution be crystallization differentiation,and enriched silver in the quartz porphyry magma;(2) contributing to form a great of quantites ore solution.Many evidences show that granite and quartz porphyry are go with to the ore in the materials such as the characteristics of rare earth elements,trace elements and oxygen,hydrogen,sulfur and lead isotopies.Because quartz porphyry is the latest stage of magma,silver was enriched in the later diagenetic and post diagenectic ore solution.Quartz porphyry is the parent rock of the deposit.