小秦岭金矿床成矿作用及成矿物质来源

Mineralization and Material Sources in the Xiaoqinling Gold Deposit

根据小秦岭地区太华群花岗-绿岩地体的形成和演化,通过太华群主要地层及岩浆岩常量元素、微量元素、稀土元素组成特征分析,对金的演化和成矿地球化学、物理化学进行分析探讨。认为本区太华群是金的矿源层,与金矿空间关系密切的燕山期文峪花岗岩体是太华群及其以下壳幔物质重熔形成的,它控制本区金异常及金矿的分布,但是岩体仅作为驱动金富集成矿的热动力,而没有提供主要的成矿物质来源。小秦岭金矿床为热液型矿床,成矿热液以岩浆水为主,混合天水成矿。成矿热液属于弱酸—弱碱性,成矿温度为中偏高温。

According to the formation and evolution of granite-greenstone terrain of Taihua Group in the Xiaoqinling district,based on the characteristics of compositions of major elements,trace elements and rare-earth elements,gold evolution,metallogenic geochemistry and physical chemistry in the Xiaoqinling gold deposits are discussed.We think that Taihua Group is one of the gold sources of deposit formation,and the Wenyu granite body of Yanshan stage,in a close relation to the gold deposits in Xiaoqinling district,is formed by remelting of Taihua Group and its below crust mantle substance.The Wenyu granite body controls the gold abnormity and distribution of gold deposits,but it only offers thermal power and offers no gold ore-forming substance.The Xiaoqinling deposits belong to hydrotherm type;the metallogenic hydrotherm is mainly magmatic water,which mixed some meteoric water to form the deposits.The metallogenic hydrotherm belongs to weak acid-alkalescent,and metallogenic temperature is moderately high.