伊犁盆地阔斯加尔铀成矿区西山窑组古地下水动力系统

研究伊犁盆地阔斯加尔地区西山窑组古地下水动力系统,总结其与铀成矿的关系,为该地区砂岩型铀矿成矿规律研究及实际的铀找矿工作提供重要的理论依据。通过分析氧化砂体厚度在平面上的变化特征,以反演层间氧化流体在平面上的推进情况,进而恢复研究区西山窑组古地下水的"补-径-排"特征。西山窑组层间氧化带主要发育在下段和上段上亚段中,下段氧化砂体厚度最大的部位主要在研究区西南方向,呈"朵状"往北东和北方向展布;上段上亚段氧化砂体最厚的部位在东南方向,且呈条带状往北西方向展布。根据氧化砂体厚度的平面展布形态,结合砂体本身的厚度以及区域水文地质背景,可以判断铀成矿时期阔斯加尔地区有两个补水方向:一个是该地区的西南方向,西山窑组下、上段的共同补水方向;另一个方向,同时也是西山窑组上段主要的补水方向,是该地区的东南方向。

Paleogroundwater Dynamics of Xishanyao Formation in Kuosijiaer Uranium Ore District in Yili Basin

This study investigated the paleogroundwater dynamic system of the Xishanyao Formation in Kuosijiaer area(Yili Basin),summarized its relationship with the uranium mineralization,and provided supports for the metallogenic regularities of sandstone-type uranium deposits and guide for future uranium prospecting in the area.By analyzing the thickness variation characteristics of the oxidized sand bodies,inverting the planar flow regime of interlayer oxidizing fluids,we reconstructed the paleogroundwater recharge-runoff-discharge characteristics of the Xishanyao Formation in the study area.Interlayer oxidized zone at Kuosijiaer was mainly developed in the Lower Xishanyao Formation and upper sub-member of the Upper Xishanyao Formation.The maximum thickness of the oxidized sand body of the Lower Xishanyao Formation occurs in the southwest,and appears as flower-shaped in the northeast and north.Maximum thickness of the oxidized sand body of the upper sub-member of the Upper Xishanyao Formation is in the southeast,and appears as strip-shaped in the northwest.Based on the distribution characteristics of the oxidized sand bodies,and considering the sand body thickness changes and the regional hydrogeological regime,two water-replenishment directions in the uranium mineralization can be determined at Kuosijiaer:(1) southwest,same in both the Lower and Upper Xishanyao Formations;(2) southeast,which was likely the main water-replenishment direction in the Upper Xishanyao Formation.