煎茶岭镍矿——是岩浆还是热液成因  

Jianchaling nickel deposit:Magmatic or hydrothermal origin?

作　　者：姜修道[1] 魏钢锋[1] 聂江涛[1] 

机构地区：[1]长安大学地球科学与资源学院,陕西西安710054

出　　处：《矿床地质》2010年第6期1112-1124,共13页Mineral Deposits

基　　金：地调项目"煎茶岭金镍矿田构造演化及成矿作用研究"(1212010611807)的资助

摘　　要：煎茶岭镍矿是秦岭造山带中至今发现的唯一镍矿床,其成矿特征在铜镍硫化物矿床中具有特殊性。通过对矿床地质、地球化学特征和成矿地质条件的综合研究,发现该矿床严格受韧性剪切带和花岗斑岩的控制,近矿围岩蚀变强烈;矿石以交代结构为特征,细脉状构造发育。矿物生成顺序研究表明,矿石中金属硫化物明显晚于超基性岩,而与其发生蚀变的时间相近,同时由于矿体附近的钠长斑岩发生了强烈的围岩蚀变,因此成矿作用也晚于钠长斑岩。矿石微量元素和稀土元素表现出明显的双重性,在继承超基性岩特征的同时,又与矿区中酸性岩存在密切的联系。在硫同位素组成上,矿石明显地富集重硫,其δ34S无论是变化范围还是平均值均远离镁铁-超镁铁质岩石,而与矿区中酸性岩中黄铁矿的硫同位素具有很好的一致性。说明该矿床应是由热液作用形成的,成因类型属岩浆热液改造型矿床。The Jianchaling nickel ore deposit is the only nickel deposit discovered in the Qinling orogenic belt,and its geological characteristics are quite unique among the Cu-Ni sulfide deposits.A comprehensive study of geological and geochemical characteristics and metallogenic geological conditions shows that the ore deposit is strictly controlled by the ductile shear zone and the granophyre,with intense wall rock alteration seen in the wall rock near the ore bodies.Ores are characterized by veinlet structure and metasomatic texture.Mineral sequence suggests that metallic sulfides in the ores were obviously formed later than the ultrabasic rock,close to the occurrence of alteration.The alteration of albitophyre near the ore body implies that the metallic sulfides were formed also later than albitophyre.The minor elements and REE in the ores show apparent dual nature,being closely related to the medium-acid rocks besides inheritance from the ultrabasic rock.In terms of sulfur isotope,the ores are evidently rich in δ34S,whose content range and average value are quite different from those of mafic and ultramafic rocks but identical with things of medium-acid rocks in the ore district.It is thus believed that this nickel deposit was formed by the hydrothermal process and belong genetically to magmatic hydrothermal reformation type.

关 键 词：地质学 镍矿床 成因类型 煎茶岭 

分 类 号：P618.63[天文地球—矿床学]