鄂尔多斯盆地南部彬县地区侏罗系直罗组古地貌及其对铀成矿的影响

发布时间：2018-11-15 15:01

【摘要】：以鄂尔多斯盆地南部彬县地区侏罗系直罗组下段为研究对象,采用层拉平法精细恢复彬县地区直罗组下段各个时期的古地貌特征并划分古地貌单元,探讨古地貌特征对有利沉积相带分布的控制,揭示直罗组下段铀储集层的空间演化特征,明确不同时期地下水流的流向,探讨古地貌特征对层间氧化带的控制作用。辫状河道砂体为有利的铀储集层,铀矿(化)体主要赋存于辫状河砂体中,受沉积古地貌控制,主要发育在下切谷中。古地貌控制了地下古水流的流向,从而控制着氧化带的发育和铀成矿。晚侏罗世,彬县地区北部为古隆起区,容易被淋滤氧化,不利于铀矿的预富集;早白垩世—古新世主成矿阶段,直罗组底部古地貌变为"东南高、北西低"特征,含氧含铀水主要来自盆地东南缘,呈扇形沿着直罗组下段辫状河道砂体渗流,形成层间氧化带。古地貌恢复对铀储集层砂体的分布特征和铀成矿规律的研究具有重要的指导意义。
[Abstract]:Taking the lower Jurassic Zhiluo formation in Binxian area of southern Ordos Basin as the object of study, the paleogeomorphic features of the lower member of Zhiluo formation in Binxian area were recovered and the paleogeomorphological units were divided into paleogeomorphological units by using stratigraphic leveling method. This paper discusses the control of paleogeomorphic features on the distribution of favorable sedimentary facies zones, reveals the spatial evolution characteristics of uranium reservoirs in the lower member of Zhiluo formation, clarifies the flow direction of groundwater flow in different periods, and probes into the control effect of paleogeomorphic characteristics on the interlayer oxidation zone. The braided channel sand body is a favorable uranium reservoir and the uranium orebody is mainly located in the braided river sand body controlled by sedimentary paleogeomorphology and mainly developed in the lower cut valley. Paleogeomorphology controls the flow of groundwater and paleocurrent, thus controlling the development of oxidation zone and uranium mineralization. In the late Jurassic, the northern part of Binxian area is a paleouplift area, which is easy to be leached and oxidized, which is not conducive to the preconcentration of uranium deposits. In the main metallogenic stage of early Cretaceous to Paleocene, the paleogeomorphology at the bottom of Zhiluo formation became "high in southeast and low in north and west". The oxygen-bearing uranium-bearing water mainly came from the southeastern margin of the basin, and the sand body of braided channel along the lower part of Zhiluo formation was fan-shaped. Cambium interlayer oxidation zone. The restoration of paleogeomorphology is of great significance to the study of the distribution characteristics and uranium metallogenic regularity of uranium reservoir sand bodies.
【作者单位】：中核集团核工业北京地质研究院;中核集团铀资源勘查与评价技术重点实验室;核工业二0三研究所;
【基金】：中核集团“龙腾2020”(编号:LTD1601-3) 中国核工业地质局项目(编号:201586) 青年科技创新团队项目(编号:地HQX1601) 国家973项目(编号:2015CB453004)联合资助~~
【分类号】：P534.52;P619.14

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