伊犁盆地砂岩型铀矿同位素地质特征

本项目试图探讨砂岩型铀矿床的同位素地质特征 ,开拓同位素地质研究的新领域。对伊犁盆地砂岩型铀矿床及其蚀源区的初步研究表明 ,该区砂岩型铀矿具有期成矿作用的特点 ,成矿年龄有 82Ma、6 0Ma、11 4Ma、7 1Ma和 3 5Ma。从含矿砂体中精选出的碎屑锆石的U Pb等线年龄为 380Ma,与蚀源区花岗岩和火山岩的年龄一致 ,从而限定了含铀砂体的物源。笔者认为 ,伊犁盆地砂岩型铀矿床具有多铀源富集的特征 ,铀源主要来自沉积过程中形成的富铀砂体 ,也有部分来自蚀源区富铀岩石风化淋滤作用而释出的铀。

The Characteristics of Isotope Geology of Sandstone-Type Uranium Mineralization from Yili Basin, Xinjiang

The isotopic geological characteristics of the sandstone-type uranium deposits and erosion area in Yili-Basin have been studied. The results showed that the sandstone-type Uranium mineralization ages were 82.4 Ma, 60 Ma, 11.4 Ma, 7.1 Ma and 3.5 Ma have been obtained. The main mineralized stage is Miocene Epoch and Pliocene Epoch of Neogene Period. The U-Pb isochron age of clastic zircons selected from ore-bearing sandstone is 308 Ma which is consistent with the ages of the granite and volcanic rocks in the erosion area. Therefore, the material source of uraniuferous sandstone was defined. The study of the U-Pb isotopic systematic evolutionary characters of ore-bearing sandstone and erosion area rocks pointed out that the sandstone type uranium deposits in Yili Basin have the characteristics of multi-source uranium enrichment. The sources include uraniumferous sandstone (mainly) formed during the deposition and the uranium leached from erosion area rocks by weathering.