吐哈盆地西南缘古流体地质作用与砂岩型铀矿成矿作用初探

Initial discussion on paleo-fluid geologic process and sandsto ne-type uranium metallogenesis at southwestern edge of Turpan-Hami bas in

笔者通过岩石后生蚀变与气 液包裹体特征研究 ,认为吐哈盆地西南缘中 下侏罗统水西沟群 (J1 -2 sh)地层存在两期明显的古流体地质作用 :早期酸性氧化古流体和晚期碱性还原古流体地质作用。前者造成本区J1 -2 sh地层由“黄色”及“红色”蚀变岩石组成的层间氧化带的广泛发育 ,该期古流体作用对铀成矿极其有利 ;后者是本区“钙质层”形成的主要原因 ,对铀成矿不利。据气 液包裹体成分测试结果初步认为 :古流体的组成主要是地下水及煤成天然气。

Through the study on features of epigenetic al te rations and fluid inclusion,two stages of obvious paleo-fluid geologic process h ave been affirmed in Shuixigou Group (J 1-2 sh),Middle-Lower Jurassic at th e southwestern edge of Turpan-Hami basin:the earlier one is an oxidizing acidic paleo-fluid and the latter one is a reducing alkalic paleo-fluid.The first on e caused extensive interlayer oxidation zone consisting of 'yellow' and 'red' alteration of rocks,and is favorable for uranium metallogenesis.The second one led to the formation of the 'calcrete',and unfavorable for uranium metallogenesis .According to the composition of gas-liquid inclusion,it is thought initially t hat the paleo-fluid is mainly composed of groundwater and gas originated from c oal.