201、325和706铀矿床蚀变带绿泥石研究

以岩矿鉴定结果和电子探针绿泥石分析数据为依据，将325、706花岗岩型铀矿床蚀变带绿泥石分为假象绿泥石和鳞片状绿泥石。后者由前者转变而成，转变过程中存在着铁的迁出与镁的加入，迁出的铁形成赤铁矿，可能是造成碱性蚀变带呈红色的原因之一。201、325铀矿床蚀变带绿泥石为铁镁绿泥石和蠕绿泥石，706铀矿床蚀变带绿泥石主要属密绿泥石和铁斜绿泥石，少数属铁镁绿泥石。研究发现绿泥石变种由蚀变带原岩的∑FeO与MgO比值大小决定，与铀矿蚀变带是否为酸性和碱性没有必然的对应关系；绿泥石晶胞中镁羟基和铝羟基相对比例大小不同，是导致其吸收位置在2259-2262nm和2348-2359nm的诊断性吸收峰发育程度存在差别的原因。

Chlorite in alteration zone of uranium deposits No.201, No.325 and No.706

According to mineralogical examination and electron microprobe data analysis, post-biotite chlorite and spheluritic chlorite are two forms of chlorites in the alteration zone of granite-type uranium deposits No.325 and No.706. As post-biotite chlorite is substituted for spheluritic chlorite, during the substitution, some Fe are released and Mg replace in, which results in the further hematization in rock. This is probably one of the reasons that red color occurs in sodium metasomatic alteration zone. The chlorites in uranium deposits No.201 and No.325 are brunsvigite and ripidolite. Most of the chlorites in uranium deposit No.706 are pycnochlorite and diabantite, while a few are brunsvigites. A new finding shows that the chlorite variety is determined mainly by ∑ FeO and MgO ratio of primary rock and is independent of alteration characteristic （acidic alteration or alkalic alteration）. The proportion of Mg hydroxyl and Al hydroxyl in the unit-cell of chlorite may cause spectrum difference of diagnostic absorptive valley position and depth at 2 259-2 262 nm and 2 348-2 359 nm.