大红山地区矿区特征及成因类型探析

On Mine Features and Genetic Type Study of Dahongshan Area

大红山铁铜矿床整体呈层状、似层状产出,它包括了7个矿带.大红山铁铜矿床形态明显受地层控制,矿体与呈层状、似层状与围岩整合接触.矿石成分主要为黄铜矿和磁铁矿,还有少量的赤铁矿、铜兰、辉铜矿、辉钴矿、黄铁矿、磁黄铁矿、方铅矿;非金属矿物还有少量电气石、磷灰石等.大红山矿区的铁铜矿分布,是高度集中于某一或者某几个区域.根据火山成矿理论,它们应该受到火山机构尤其是火山口的控制,从火山口向四周扩散,矿体逐渐变薄、变贫.对于其矿床成因,目前较一致的看法是"火山喷发—沉积—后期变质改造",即大红山的成矿物质在早期由火山喷溢到表面沉积,形成矿化点、带,后期经过一系列区域变质作用、热液作用改造富集成矿.对于近年来不少学者将其归入IOCG矿床,尽管大红山地区有一些IOCG矿床特征,但都没有充分的证据证明它.

Dahongshan Iron-Copper deposit is a layered or statiform deposit which can be divided into seven ore belts.Its mineral composition mainly includes chalcopytite,magnetite,minor hematite,malachite,chalcocite,cobaltite,pyrite,pyrrhotite galena;its non-metallic mineral includes minor tourmaline,apatite and so on.The distribution of iron and copper deposits in Dahongshan Mine Area are highly concentrated in one or a few regions.According to volcanic ore-forming theory,these deposits should be controlled by volcanos especially craters.With the distance added between crater and deposit,the ore body gradually become thin and poor.For its genesis,＂volcano eruption-sedimentary-metamorphism＂mechanism is now widely accepted.The ore-forming materials of Dahongshan Mining Area were ejected onto the surface by early volcano activities,forming the mineralization spots and belts.Later with a series of regional metamorphism and hydrothermal alteration,they gradually changed into deposits.In recent years,many scholars classified Dahongshan deposits as IOCG deposit,though they have some similar features with IOCG deposit,there is still no adequate evidence to approve it.