【摘要】：納嶺溝鈾礦床位于鄂爾多斯盆地北東部,是我國近年發(fā)現(xiàn)的一個特大型砂巖鈾礦床,鈾礦體賦存于中侏羅統(tǒng)直羅組下段河流相砂體中,受古層間氧化帶控制,呈板狀。鈾礦物主要為鈾石、瀝青鈾礦和鈦鈾礦,其中鈾石是最主要的鈾礦物。瀝青鈾礦中w(CaO)較高;鈾石中w(UO_2)偏低、w(SiO_2)偏高,w(UO_2)/w(SiO_2)達到1:1.29,遠低于正常值;鈦鈾礦則呈現(xiàn)U低Ti高的特點。根據(jù)各鈾礦物的形成、富集機理,認為納嶺溝鈾礦床在古層間氧化發(fā)育階段賦礦砂體屬于酸性環(huán)境,SiO_2活度較低,形成鈾礦物主要為瀝青鈾礦。始新世晚期及以后,氧化作用不發(fā)育,賦礦砂體被二次還原,巖石地球化學環(huán)境由酸性轉(zhuǎn)變?yōu)槿鯄A性,SiO_2活度增大,使早期階段形成的瀝青鈾礦轉(zhuǎn)變?yōu)殁櫴�。鈦鈾礦主要是在氧化—還原作用下由含鈾溶液中的鈾(UO_2~(2+))交代重礦物—鈦鐵礦中的Fe2+而形成。
[Abstract]:Naling Gou uranium deposit is located in the north east of Ordos Basin. It is a very large sandstone uranium deposit discovered in China in recent years. The uranium orebody occurs in the fluvial sand bodies of the lower member of the Zhiluo formation of the Middle Jurassic, and is controlled by the paleo-interlayer oxidation zone and is in the shape of a plate. Uranite is mainly composed of uranite, pitchblende and ilmenite, among which uranite is the most important uranite. The w (CaO) in pitchblende is higher than that in uranite, and the ratio of, w (UO_2 / SiO_2 in uranite is 1 鈮，

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