某岩体两个铀矿床中沥青铀矿的特征对比及其成因探讨

沥青铀矿是我国花岗岩型铀矿床的主要工业铀矿物,对其特征的研究往往能揭示其形成条件和环境。本文所讨论的两个矿床中的沥青铀矿在各方面表现出了一系列的差异,表明它们在形成条件上有所不同。

Characteristic Contrast of Pitchblende in Two Uranium Deposits in Some Massif and Approach toTheir Genesis

The massif is the oldest (760 Ma.)uraniferous granite known in South China. The massif is represented by two types , of uranium mineralization; the chlorite-vein type (deposit A) and the microquartz-vein type (deposit B). The deposit A is located near the contact zone of the massif and formed at Hercynian period (330 Ma. ago).The deposit B is located in the, massif and occurred at Himalayan period (47 Ma. ago). Characteristic contrast of physical properties, chemical composition, isoto- pic composition of. lead and others of pitchblende in two uranium deposits fully reflects geochemical setting, characteristic of ore-forming fluids and source of ore. Pitchblende in the deposit A has larger cell size, higher reflectan- ce, smaller oxidation coefficient, to be xiched in Mg, Fe and A1 characterized in metamorphic rock, higher mineralization temperature anal very low content of initial lead. The reflect that the pitchblende has formed at hypogenic setting with high temperature and pressure of mineraIization was related to meta- morphism. Pitchblende in the deposit B has smaller cell size, lower reflectan- ce, larger oxidation coefficient, Lower mineralization ternperature, rich calcium and initial lead, typical colloid texture and vein filling, which all indicate that the pitchblende has formed at supergene setting with middle-low temperature and pressure of mineralization was related to hypergene hydrothermal pro- cess.