云南墨江金厂金矿床矿物成因和物质来源研究

摘要

墨江金厂金矿床有时期长、周期复杂、来源深部的特点,可是矿区地质研究薄弱.根据研究发现,在金厂金矿蚀变带出现的镁铬铁矿、硬铬尖晶石与铬叶绿泥石等标示成因与超基性岩有关的标型矿物,在蚀变岩与矿体中还较普遍较高量地出现以Cr为特征的标示与超基性岩有关的矿物成分标型.Mg是金厂金矿矿物成分标型中的第二特征,与Cr同来自金厂超基性岩,充分显示成因矿物学中矿物标型相应性.Ni仅次于Cr、Mg,是金厂金矿矿物成分标型中的第三大特征,金厂组中成因标志与蚀变围岩中的Ni的来源与Cr、Mg相同,主要也是来自金厂超基性岩体.Au与Cr、Mg、Ni、Pt等Pt族元素形成的矿物元素组合普遍出现于金矿体与蚀变岩中,是指示Au与幔源超基性岩有关的成因标志.S与Au、Ni矿化均主要来自金厂超基性岩体,而且是由此一同向外扩散运移沉淀的.%Jinchang Au deposit in Mojiang is characterized by long history,complicated periods and deep original source,but the geologic research is lacked in this area.Our research reveals that the typomorphic minerals (such as magnesiochromite,chromopicotite,kaemmererite etc.) which indicate that the ultrabasic rock is involved in genesis is occur in Jinchang alteration zone,and a relatively large amount of typomorphic mineralogical composition which is characterized by Cr and indicates that the ultrabasic rock is involved in genesis occurs commonly in the alternative rocks and the ore-bodies.Mg is the second characteristic of typomorphic mineralogical composition of Jinchang Au deposit.Both Mg and Cr originate from Jinchang ultrabasic rock and it shows the correspondency of mineral typomorphism which is introduced in genetic mineralogy.Ni,which ranks after Cr and Mg,is the third characteristic of typomorphic mineralogical composition of Jinchang Au deposit.The genesis index of Jinchang formation and original source of Ni in alteration zone is identical with those of Cr and Mg,namely Jinchang ultrabasic rock.Mineral element combination which includes Au and Pt group elements (Cr,Mg,Ni,Pt) commonly occurs in Au ore-bodies and altered rocks and it is a genesis index which indicates that Au is related to mantle-derived ultrabasic rock.S and the mineralization of Au and Ni mainly originate from Jinchang ultrabasic rock,and they simultaneously diffuse,migrate and precipitate from then.