摘要
河北丰宁营房铅锌银矿床产于一近南北向的中型韧性剪切带中。矿体定位于燕山早期粗粒钾长花岗岩与下元古界红旗营子群地层构造接触带中。矿体埋藏浅、厚度大、品位高，已构成铅锌银共生矿床。主要银矿物有银黝铜矿、辉银矿、螺状硫银矿、浓红银矿及自然银等。银主要以单矿物形式赋存于方铅矿及闪锌矿中，少量存在于脉石中，极少量以类质同像或次显微包体形式存在于硫化物和硫盐矿物中。银的富集主要与方铅矿、闪锌矿及黄铁矿关系密切，而单一黄铁矿型或黄铁多于方铅矿＋闪锌矿类型的矿石，银矿化一般不好。银矿化程度与糜棱岩化程度及硅化、绢云母化程度正相关。经初步研究，矿体的直接围岩（红旗营子群变质岩）为初始矿源层，而花岗岩的侵入，只起到了热动力源的作用。矿源层中的成矿物质在韧性剪切糜棱岩化过程中，在热动力变质作用下发生变质分异而活化、迁移、富集成矿。矿床成因类型应属变质（热液）分异或韧性剪切糜棱岩型铅锌银矿床。
Yingfang Pb-Zn-Ag deposit lies in a S-N direction medium ductile shear zone,its mainore body occurs in the contact zone between coarse Or-granite of early Yanshanian andHongqiyingzi Group of Lower Proterozoic.With shallow burial,big thickness,high grade andeasy dressing,it is a minable Pb-Zn-Ag associated deposit.The main Ag minerals are as follows:Ag-tetrahedrite,argentite,acanthite,pyrargyriteand native silver.Silver bearing minerals are mainly simple and occur in galena and spha-lerite,minorly in gangue minerals,very little in sulphide and sulfate minerals as isomor-phisms and submicro inclusions.The enrichment of Ag has generally close relation with gale-na and sphalerite,but the simple type of pyrite,or pyrite dominating over galena and spha-lerite,Ag mineralizations are weak.In the region,Ag mineralization is also normally correlat-ed with mylonite,silication and sericitization.Through preliminary study,the author considers that the counting rocks of HongqiyingziGroup are the source beds,granite intrusion only provides the thermal source.During myloni-tization in ductile shear zone the source rocks are suffered metamorphic differentiation,acti-vation,migration and resulted in the formation of ore deposits.So,the deposit belongs to thetype of metamorphic(thermal fluid)differentiation or ductile shear mylonite.
关键词
矿源层
铅锌银矿床
赋存状态
富集规律
source bed,Hongqiyingzi Group,ductile shear zone,Pb-Zn-Ag deposit,Yingfang of Hebei
