论铀成矿过程中的气还原作用

热力学计算及成矿实验结果表明Ｈ２，ＣＨ４，ＣＯ和Ｈ２Ｓ等气体能作为还原剂使ＵＯ还原成ＵＯ２（晶质铀矿）。尽管在许多铀矿床中存在的黄铁矿能作为还原剂，但上述还原性气体是比黄铁矿更有效的还原剂。一些矿床的钻探资料及流体包裹体中气体含量测定结果证实了上述气体的存在。文中提出了气还原作用这一概念，它被认为是澳大利亚、加拿大和中国等地不整合脉型铀矿床及其他一些脉型铀矿床成矿富集的重要机制。

GAS REDUCTION:AN IMPORTANT FACTOR IN THE FORMATION OF URANIUM DEPOSITS

Thermodynamic calculations show that gases such as H2,CO,CH4,and H2S can react upon UO in aqueous solutions at low temperatures leading to the precipitation of uraninite.Although pyrite may serve as the reductant and is present in many deposits, reducing gasesare regarded here as more efficient reductants which has been supported by experimentalstudies. The evidence of activity of the gases is preserved in fluid inclusion. A concept of gasreduction is proposed, and its efficiency is considered to be one of the reasons why the unconformity-type uranium deposits in Canada, Australia, and China have high uranium grades(10% or more ).