豫北安林地区矽卡岩型铁矿床硫和铅同位素特征及其意义  

Sulfur and lead isotopic characteristics and metallogenic significance of skarn iron deposits in Anlin area,North Henan

作　　者：郭大鹏 袁跃清 赵彦巧 GUO Dapeng;YUAN Yueqing;ZHAO Yanqiao(Henan Research Centre of Mineral Exploration Engineering and Technology for Non-ferrous Metals Resources,Zhengzhou 450016,Henan,China;The First Geological Brigade of Henan Bureau of Nonferrous Metals Geology and Mineral Resources,Zhengzhou 450016,Henan,China)

机构地区：[1]河南省有色金属矿产探测工程技术研究中心,河南郑州450016 [2]河南省有色金属地质矿产局第一地质大队,河南郑州450016

出　　处：《矿产与地质》2021年第3期473-479,502,共8页Mineral Resources and Geology

基　　金：河南省国土资源厅地质矿产科技攻关项目“河南省安林地区铁矿深部成矿预测研究”(编号:〔2010〕007)资助。

摘　　要：豫北安林地区接触交代型(矽卡岩型)铁矿是典型的邯邢式铁矿,其成矿物质来源以及与膏岩层的关系缺少有效的研究。通过选取其中典型矿床矿石中的黄铁矿进行了S、Pb同位素测试,结果表明,矿石中硫化物的δ^(34)S值为11.8‰~16.2‰,极差为4.4‰,平均值为13.75‰,介于岩浆硫与沉积膏盐硫之间,表明成矿物质既具有岩浆源硫特征,又接受了地下热水及膏盐层中的部分^(34)S混入。矿石矿物的铅同位素组成变化较小,^(206)Pb/^(204)Pb比值为17.057~18.537,平均值为17.546;^(207)Pb/^(204)Pb比值为15.343~15.582,平均值为15.440;^(208)Pb/^(204)Pb比值为37.053~38.398,平均值为37.601。铅同位素组成与特征参数(Δβ与Δγ)显示,矿床中的铅主要来源于深部幔源,与岩浆作用有关,并有下地壳铅的混入。矿床的成矿作用与燕山期岩浆侵入岩活动存在较密切的关系,广泛分布的膏盐层为矿床的形成提供了有利条件。The iron deposit of contact metasomatic type(skarn type)in Anlin area of North Henan is typicaliron deposit of Han-Xing type.There lacks the effective research for the source of its ore-forming materials and the relationship with the gypsum rock layer.In this paper,S and Pb isotope analysis of pyrite from the ore of typical deposit is carried out.The result shows that the value ofδ^(34)S of sulphide in the ore is 11.8‰-16.2‰,with the range of 4.4‰and the average value of 13.75‰.The above mentioned values are between those of magmatic sulfur and those of sedimentary gypsum-salt sulfur.It is indicated that the ore-forming material not only has the feature of magmatic source sulfur but also accepts the mixture of partial^(34)S of underground hot water and gypsum-salt layer.The composition of Pb isotope in the ore varies slightly.^(206)Pb/^(204)Pb is 17.057-18.537 with the average value of 17.546.^(207)Pb/^(204)Pb is 15.343-15.582 with the average value of 15.440.^(208)Pb/^(204)Pb is 37.053-38.398 with the average value of 37.601.The composition and characteristic parameters of Pb isotope(ΔβandΔγ)show that Pb of the deposit is mainly derived from the deep mantle and related to magmatism,accompanying with involvement of Pb from the lower crust.The mineralization of the deposit is closely related to the activity of Yanshanian magmatic intrusive rock.The extensive distribution of gypsum-salt layer provides a favorable condition for the formation of the deposit.

关 键 词：铁矿床 硫铅同位素 地球化学 矽卡岩型 安林地区 豫北 

分 类 号：P618.31[天文地球—矿床学] P597[天文地球—地质学]