【摘要】 <正> 六二一矿床的近矿围岩遭受了强烈的碱性蚀变作用,主要有钠长石化、铁白云石化、红化及黑化(铁绿泥石化)。作为变价元素和色素离子的铁在交代作用中是非常活泼的,本文从研究近矿围岩蚀变过程中铁的化学组分和矿物组分变化入手,探讨了蚀变晕圈中铁的两种主要表现形式——“红化”和“黑化”成因以及铁铀之间的关系;提出“红化”的发生不是由于低价铁氧化成高价铁的“价态转换”的结果,富铀矿化的出现即沥青铀矿的沉淀,也不能简单地用铁、铀间的氧化还原反应来解释;阐明了交代过程中铁质组分的“物态变异”——“粉末化”是导致岩石变红的原因;论述了蚀变矿化过程中铁的再分配和局部迁移、聚集的地球化学行为。更多还原

【Abstract】 Our studies indicate the redistribution and local migration of iron and the change of its physical state, ibut no variations in the total content and the contents of Fe3+ and Pe2+ in the process of near-ore wallrock alteration of uranium deposit No. 621. An ex-planation is given of why the near-ore wall rocks have become red. It is also pointed out that there is a tendency for Fe2+ to migrate and accumulate toward the ore-bearing terrain, resulting in the formation of coexisting Fe-chlorite and pitchblende and thus the. phenomenom of "darkening" which is closely related to uranium-rich minerali za-tion.更多还原