鄂尔多斯盆地东胜地区直罗组高分辨率层序地层与铀成矿关系探讨  

The discussion on the relationship between high-resolution sequence stratigraphy and uranium mineralization of Zhiluo Formation in Dongsheng area,Ordos basin

作　　者：陈晓林[1] 向伟东[1] 李田港[1] 方锡珩[1] 庞雅庆[1] 

机构地区：[1]核工业北京地质研究院,北京100029

出　　处：《铀矿地质》2007年第1期30-37,共8页Uranium Geology

摘　　要：文章综合利用岩心、露头、测井资料，运用高分辨率层序地层学基本理论和方法，对东胜地区直罗组地层进行不同级次基准面旋回的层序划分，共识别出8～14个短期旋回、3个中期旋回，并对不同级次基准面旋回的结构类型、叠加样式进行探讨。分析了中期旋回中可容纳空间与沉积物补给通量比值（A／S）的变化对河道砂体规模、储集性能的控制作用，指出与MSCl对应的直罗组底部的辫状河道砂体最有利于铀成矿，而与MSC2、MSC3对应的两套曲流河砂体则不利于铀成矿。文中最后分析了含铀含氧水在砂体中的运移路径，并试图回答主铀矿体为什么主要分布在砂体的中、上部，而在其翼部的矿体中，为什么下翼比上翼的厚度要大。According to the data of drill cores, outcrops and well loggings, two orders base-level cycles are recognized from Zhiluo Formation in Dongsheng area, which consist of 8-14 short-term base-level cycles and 3 mid-term base-level cycles, and their structural types and stacking patterns are discussed by using principles and methods of high-resolution sequence stratigraphic theory. Based on the correlation of mid-term base-level cycles, the control of the A/S （Accommodation/Sediment supply） ratio in mid-term base-level cycles on the scale of sand bodys and physical properties of reservoir is analysed. Studies show that the sand bodies of braided stream in MSC1 of Zhiluo Formation are favourable to uranium mineralization, however, the sand bodies of meandering river in MSC2 and MSC3 are not favourable to uranium mineralization. The change of the A/S results in the difference in characters of sand body , such as physical properties, continuity and so on, which control the fluid flowing path. After discussing the immigration of uranium-bearing oxidizing ground water in the braided channel sand bodies, the paper trys to present the answers to the question of why the host orebody occurs mainly in the middle and upper sand body which the lower limb is thicker than the upper limb in the limb orebodies.

关 键 词：东胜铀矿床 直罗组 高分辨率层序地层 基准面旋回 铀成矿 

分 类 号：P539.2[天文地球—古生物学与地层学]