冀北地区火山岩型隐伏铀矿地球化学勘查方法试验研究

Experimental Study of Geochemical Exploration Methods for Volcanic-Type Concealed Uranium Deposit in Northern Hebei

冀北地区是火山岩型铀矿产出有利区,该区发现的460铀钼矿是北方地区典型的火山岩型铀矿床。在460铀钼矿体上方开展了土壤细粒级测量和金属活动态测量2种地球化学勘查方法的试验工作,目的是为该地区铀矿找矿工作提供地球化学方法指导。剖面测量结果显示,在铀钼矿体上方,土壤细粒级和金属活动态测量都存在明显的U、Mo异常,其中,土壤细粒级U、Mo异常强度和规模较活动态U、Mo突出。U活动态含量以黏土吸附态最强,表明活动态铀以细粒级黏土吸附为主,Mo活动态含量以水溶态最强,表明钼主要以可溶解的钼酸盐形式存在。土壤细粒级和金属活动态面积性测量圈定的异常分布范围与矿区的分布较为一致,说明这2种方法对圈定隐伏火山岩型铀矿都是有效的。

Northern Hebei is a favorable area of U ore-prospecting . The 460 uranium-molybdenum deposit discovered in this area is the largest volcanic-rock type uranium- molybdenum deposit in North China. Two kinds of methods for geochemical exploration were adopted for the 460 uranium-molybdenum deposit in or- der to find the suitable geochemical method for the uranium prospecting in the area. Soil profile survey re- sults show that U and Mo anomalies are delineated in soil quantity and active state above uranium-molyb- denum ore body; however, U, Mo total measurement anomalies are large in intensity and extension com- parison of U, Mo active state. U content in clay adsorption state and Mo content in water soluble state of active state is the strongest. Soil area survey reveals that the abnormal distribution of the two methods is more uniform in the mining field. This illustrates the two methods are effective in identifying areas of con- cealed volcanic-rock type uranium deposits.