半干旱草原景观区鹿儿坝金矿的勘查地球化学特征  

CHARACTER OF GEOCHEMICAL EXPLORATION OF THE LUERBA GOLD DEPOSIT IN THE SEMIARID GRASSLAND LANDSCAPE AREA OF GANSU PROVINCE

作　　者：尤关进[1] 何进忠[1] 

机构地区：[1]甘肃省地质调查院,甘肃兰州730000

出　　处：《物探与化探》2010年第3期298-302,共5页Geophysical and Geochemical Exploration

摘　　要：鹿儿坝金矿中,与金矿化密切相关的蚀变有硅化、黄铁矿化、碳酸盐化,在地表主要表现为存在褐铁矿、黄钾铁矾、高岭土等矿物。岩石地球化学研究表明,Au与As的关系密切,Sb、Hg、Au、As一起构成Au的近矿—矿上元素;Au与As、Zn相对稳定地存在于同一种矿物中,如黄铁矿、毒砂。这种关系在土壤中得到继承,而在水系沉积物中基本瓦解。因此,岩石测量和土壤测量中,Au、As是最佳指示元素;水系沉积物测量中,最佳指示元素是Au、As、Sb。Au在表生介质中的贫化富集过程,在矿区才有较为显著的表现,并且主要发生在由土壤进入水系沉积物这一环节。汇水盆地内地表流水机械混匀作用、分选作用及样品加工过程中的筛分,是水系沉积物中Au含量适度降低的决定性因素。在正常背景地带的次生介质中,并不存在显著的贫化富集过程。The alterations related to gold minerlization in the Luerba gold deposit are silicification,pyritization and carbonatization,which find expression in the existence of limonite,jarosite and kaolin at surface.Litho-geochemistry of the ore deposit indicates that Au and As are closely related to each other,Sb,Hg,Au and As constitute near-ore or distal indicators of Au,and Au,As and Zn stably exist in such minerals as pyrite or arsenopyrite.These relationships are inherited in soil but disintegrated in stream sediments.Therefore,Au and As can be selected as indicator elements in litho-geochemical survey and soil geochemical survey,whereas Au,As,and Sb should be taken into account together in stream sediment survey.The dilution or concentration of Au in surface materials only markedly manifest itself in the mining area,and basically takes place at the step of migration from soil to stream sediments.The mechanical mixing and sorting of the stream and the sieving during sample preparation are decisive factors responsible for the reasonable decrease of gold content.In the secondary material of the background area,there is no remarkable dilution or concentration of gold.

关 键 词：金矿 半干旱草原微景观区 表生地球化学 甘肃鹿儿坝 

分 类 号：P632[天文地球—地质矿产勘探]