吐哈盆地砂岩型铀矿U-Pb同位素地质特征

Isotope Geology of the Sandstone Type Uranium Deposit in Turpan-Hami Basin

吐哈盆地十红滩砂岩型铀矿主要成矿年龄为 4 8± 2Ma、2 8± 4Ma。盆地西南部蚀源区觉罗塔格山片麻状花岗岩的形成年龄为 4 2 2± 5Ma、斑状花岗岩的形成年龄为 2 6 8± 2 3Ma。赋矿地层西山窑组 (J2 x)砂体碎屑锆石U Pb等时线年龄为2 83± 6 7Ma ,证实花岗岩侵入体是含矿砂体的主要物质来源。含矿层位的富铀沉积砂体及蚀源区富铀的岩体、石炭系碎屑岩以及火山碎屑岩等 ,构成铀成矿铀源。

This paper expounds isotope characteristics of the Shihongtan in-situ leachable sandstone-type uranium deposit in the southwestern part of Turpan-Hami basin. The uranium mineralization ages are 48±2 Ma and 28±4 Ma. The gneissic granite and the porphyritic granite in the southwesten area have ages of 422±5 Ma and 268±23 Ma respectively. The U-Pb age of clastic zircons from the ore-bearing sandstone is 283±67 Ma,which corresponds to the age of gneissic granite of the source area and hence implies that the granite intrusives serve as the material sources of uraniferous sandstone. Uraniferous sandstone accumulated during the deposition and the uranium leached from the source area rocks by weathering are main sources for uranium mineralization.