栗木矿田鱼菜花岗岩型锡钨矿床

摘要

栗木矿田花岗岩是一个燕山早期同源同期不同阶段侵位的复式岩体.鱼菜花岗岩型锡钨矿床与复式岩体中第二阶段花岗岩有关.岩石化学、稀土及其它微量元素资料表明,鱼菜花岗岩属超酸性过铝富碱一类岩石.矿体赋存于隐伏岩体浅部.矿石矿物锡石、黑钨矿以浸染状和细脉状产出.在含矿岩体钠长石化阶段形成锡矿化,云英岩化是锡、钨矿化的高峰阶段,在晚期中一低温热液作用阶段也有部分锡、钨矿化,显示锡钨具有多阶段成矿、矿化延续时间长的特点.研究指出,隐伏含矿岩体的顶上带发育多种类型线细脉及细晶岩脉,可作为预测寻找隐伏花岗岩型矿床的标志之一.通过鱼菜花岗岩型锡钨矿床和矿田与第三阶段花岗岩相关的锡铌钽矿床特征对比研究表明,尽管两类矿床属同一成因系列,有共同的基本特征,但仍存在一系列差异,这些不同特征很可能与其成矿花岗岩的不同演化程度有关.%Granite in Limu orefield is the early Yanshanian granite in Limu composite pluton, which is a set of congeneric and contemporaneous rocks in the different instructive stage.Yucai granite type tin-tungsten deposit is related to the second stage of composite pluton.Based on the studies of petrochemistry, characteristics of rare earth and trace elements, it is indicated that Yucai granite is ultra-acid rock and characterized by superaluminous and rich alkali.The orebody occurs in the shallow of hidden granites, which have disseminated and veined structures of cassiterite and wolframite.Not only albitization and greisenization but also medium-low temperature hydrothermalism in ore-bearing granite are closely related to Sn-W mineralization, it is indicated that mineralization is featured by multistage and continuing a long time.The study on hidden granite type deposit, there are many types of veinlet or aplite dykes in the top belt of hidden granite.The model is applied to the prediction for the hidden granite type deposit.Comparison studies on mineralization characteristics of Yucai granite type tin-tungsten deposit and the third Stage of granite type tin-tungsten-niobium-tantalum deposit in Limu orefield, which are resulted from the similarities in their genetic series and basic characteristics, differences in many aspects.These differences are probably related to different evolutionary stage of ore-bearing granite.