二连盆地哈达图古河道砂岩型铀矿成矿地球化学特征研究

Geochemical Characteristics of Hadatu Paleo-channel Sandstone Type Uranium Deposit in Erlian Basin

二连盆地是我国北方重要的油、煤、铀能源盆地,盆地内铀矿主要发育砂岩型铀矿。对盆地内哈达图古河道砂岩型铀矿中氧化带、过渡带及还原带砂岩进行研究。结果表明,三组样品中相对富集的元素有Rb、Mo、Sb、Ba、W、Tl、Pb、U,相对亏损的元素有Li、Sc、V、Cr、Ni、Cu、Sr、Y、In、Nb、Ta、Zr、Hf,且过渡带具有极高的U峰值(499.00×10^-6~3887.00×10^-6),平均值为2007.80×10^-6,呈现出强烈的富铀特征。Eu均表现为负异常,Ce表现为弱负异常,Eu的亏损反映成矿环境为还原环境,与铀成矿的形成机理相符。同时过渡带的△Eh和pH值均有利于铀矿床的形成,说明该地区具有比较好的铀成矿潜力。

Erlian Basin is an important oil,coal and uranium energy basin in the north of China.Sandstone type uranium deposits are mainly developed in this basin.The sandstones of oxidation zone,transition zone and original zone in Hadatu paleo-channel sandstone type uranium deposits were studied.For the three groups of samples,the relatively enriched elements are Rb,Mo,Sb,Ba,W,Tl,Pb and U,while the relatively deficient elements are Li,Sc,V,Cr,Ni,Cu,Sr,Y,In,Nb,Ta,Zr and Hf.Moreover,the transition zone has a very high U peak,ranging from 499.00×10^-6to 3887.00×10^-6,with an average of 2007.80×10^-6,showing a strong uranium-rich characteristic.The three groups of samples all show Eu negative anomalies and weak Ce negative anomalies.The depletion in Eu indicates that the metallogenic environment is a reductive environment.It is consistent with the formation mechanism of uranium mineralization.Meanwhile,delta Eh and pH values in the transition zone are conducive to the formation of uranium deposits,indicating that this region has a relatively good potential for uranium mineralization.