鄂尔多斯盆地直罗组砂体地球化学特征及其铀成矿作用

Geochemical characteristics and uranium metallogenesis of sand bodies in Zhiluo Formation Ordos Basin

通过对东胜及外围地区直罗组砂体的常量元素、微量元素、有机质含量及ΔEh值等地球化学特征参数的对比分析,认为东胜地区直罗组砂体不仅具有强的还原能力,而且砂体遭受后期改造作用也明显,其铀成矿的地球化学条件明显好于其他地区;神木地区砂体虽然具有一定的还原能力,但砂体后生改造作用差,其铀成矿条件不如东胜地区;榆林—横山地区砂体后生改造作用较强,但砂体还原能力较差,铀成矿条件也不如东胜地区;安塞地区砂体还原能力差,后生改造作用也差,因而其铀成矿条件最不利。

Analyses and contrasts of geochemical characteristics such as constant elements, trace elements, contents of organic matter. AEh value and so on of sand bodies of Zhiluo Formation in Dongsheng area and its adjacent areas show that the sand bodies of Zhiluo Formation not only have intensive reducing capacity but also suffer from relatively intensive oxidation in Dongsheng area and thus its metallogenie conditions for uranium mineralization are better than those in other areas. The sand bodies in Shenmu area just have certain reducing capacity, but alter poorly and thus, its metallogenie conditions for uranium mineralization are not as good as those in Dongsheng area. The sand bodies in Yulin-Hengshan area have suffered relatively intensive oxidation, but their reducing capacities are relatively poor and thus, their metallogenie conditions for uranium mineralization are not as good as those in Dongsheng area. The sand bodies in Ansai area have poor reducing capacity and alter poorly and thus their metallogenie conditions are the most disadvantageous for uranium mineralization.