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本文介绍了门多萨省San Rafael,Sierra Pintada地区Cochico群(二迭-三迭系)中砂岩型铀矿床成因的研究情况。讨论了铀源、搬运以及沉淀等问题。晶质铀矿和钛铀矿是主要铀矿物,它们产在砂岩的基质内。凡有氧的地方,就有水合铁氧化物沉淀;γ-Fe_2O_3·_nH_2O类型(已经穆斯堡尔谱法确定)沉淀在含水层的上部,此处CO_2分压较低,常形成微红或微红-褐色层。 CO_2分压也可以确定生物作用,如细菌的分布情况。细菌一般分布在含水层上部适合其发育和活动的较有利环境里。在相对应的局部还原层位中,多出现UO_2沉淀;所以,铀多富集于微红或微红-褐色砂岩层中。这些岩层样已被穆斯堡尔谱证实。使用穆斯堡尔法在室温及液-氮温度下对所挑选的样品进行了研究。根据研究,样品分成了四组。对所有样品中的绿泥石族矿物,在歪曲的八面体位置上做了Fe~(2+)离子鉴定。 Fe~(3+)含量低的样品相当于灰色砂岩,它们蚀变程度小,没有含铀溶液现象。相反,绿泥石中Fe~(3+)含量高的样品,也含有纤铁矿或磁赤铁矿(或赤铁矿),并且与微红或微红-褐色砂岩相对应,其蚀变程度较高并有铀矿物产出。
This paper presents the study of the genesis of sandstone-type uranium deposits in the Cochico Group (Permian-Triassic) in San Rafael, Sierra Pintada, Mendoza. Uranium sources, handling and sedimentation were discussed. Crystal uranium and titanium uranium is the main uranium minerals, which are produced in the sandstone matrix. Where aerobic iron oxide hydrate precipitation; γ-Fe_2O_3 · nH_2O type (already Mossbauer spectroscopy) precipitation in the upper aquifer, where CO_2 partial pressure is low, often forming a reddish or Reddish-brown layer. CO 2 partial pressure can also determine the biological role, such as the distribution of bacteria. Bacteria are generally distributed in the upper aquifers suitable for their development and activity of the more favorable environment. UO 2 precipitates more in the corresponding locally reduced beds; therefore, uranium is enriched in reddish or reddish-brown sandstones. These rock formations have been confirmed by Mossbauer spectroscopy. Selected samples were studied using Mossbauer method at room temperature and liquid-nitrogen temperature. According to the study, the samples were divided into four groups. For all the chlorite minerals in the samples, Fe2 + ions were identified at the distorted octahedral sites. Samples with low Fe 3+ content corresponded to gray sandstones, which had little alteration and no uranium solution. In contrast, samples with high Fe 3+ content in chlorite also contain lepidocrocite or maghemite (or hematite) and correspond to reddish or reddish-brown sandstones. The alteration To a high degree and uranium mineral output.