河南内乡牧虎顶花岗岩特征及与金矿的关系

THE FEATURES OF MUHUDING GRANITE AND TTS RELATION TO GOLD DEPOSITS IN NEIXIANG HENAN

东秦岭造山带的二郎坪—夏馆地区,发育一套火山-碎屑岩建造,并有大量花岗岩侵入体分布。重点研究了牧虎顶花岗岩的特征及与金矿的关系。该岩体副矿物含量高,组合复杂;SiO2含量高,变化大;Au、Ag等成矿元素和Sr、Ba等微量元素含量高而Rb、Co、Ni等含量低;富轻稀土,具中等负铕异常。据上述特征并结合其他许多资料综合分析表明,牧虎顶花岗岩属加里东期陆壳改造重熔型花岗岩。本区花岗岩与金矿有密切成因联系。矿床地质地球化学研究表明,金矿床的部分成矿金属物质和成矿流体及全部硫源来自花岗岩或岩浆热液,岩浆活动并为地层中金的活化迁移和聚集提供了热动力,因而花岗岩是本区金矿形成的重要因素,今后应主要在含矿花岗岩体及其附近开展金矿勘查工作。

There develops a formation of pyroclastic rock and distribute a lot of granite intrusives at the area from Erlangping to Xiaguan of eastern Qinling orogenic belt.The authors mainly study the features of Muhuding granite and its relation to gold deposits.The accessory mineral of the granite is high in content and complex in composition;the content of SiO2 is high and varies a great deal;the metallogenic elements such as Au?Ag etc.and the microelements such as Sr?Ba etc.are high in content,while Rb?Co?Ni etc.are low;the light rare earth ellments are rich and Eu is in the middle negative anomaly.According to the above features and the analyses of many materials,it is concluded that Muhuding granite belongs to the type of continental crust reforming and remelting in Caledonia period and there is an intimate relationship between the granite and gold deposits.The study of geology and geochemistry of gold deposits proves a part of the metallogenic liquid and metallic materials and all of the sulfur resource of gold deposits come from the granite of magmatic hydrothermal.The magmatic activity provides thermal dynamo for the remobilization and the assemblage of gold in the strata.So granite is the main factor of forming gold deposits in this area.The exploration of gold deposits should mainly focused in and near the metallogenic granite mass in the future.