二连盆地砂岩型铀矿找矿中的地球物理标识

Geophysical Indicators of Erlian Basin Sandstone-type Uranium Deposits

基于对二连盆地砂岩型铀矿的航空放射性测量、重磁测量、电性测量异常特征以及地震勘探反射特征的分析,并结合砂岩型铀矿成矿规律与成矿条件,推导出一套醒目的在砂岩型铀矿中找矿的标识:γ高异常附近地区为铀源点或者直接是铀矿床所在地;断裂构造是还原性物质的存储(炭屑)和运输(H2S、烃类)通道,在有利铀成矿区构造断裂周围地层往往会形成一个氧化-还原过渡带;凹陷斜坡为砂岩型铀成矿提供了一个良好的水动力条件,在凹陷边缘往往会形成铀矿带或者铀矿床。此外,通过详细剖析、对比航空放射性测量、重磁测量、电性测量异常特征以及地震勘探反射特征,发现利用地球物理方法可描绘基底与沉积物(主要是砂岩与泥岩)形态,分析沉积相,并可以得出砂岩型铀成矿环境与成矿规律。

Based on the characteristics of airborne radioactivity survey anomaly,gravity and magnetic measurement anomaly,electrical measurement anomaly and the seismic reflection characteristics of sandstone-type uranium deposit in Erlian basin and combined the metallogenic regularity and conditions of sandstone-type uranium metallogenic deposits,a set of eye-catching prospecting indicators in the sandstone-type uranium deposits are deduced.It is confirmed that the areas surrounding γhigh anomalies can be the source of uranium or directly the location of uranium deposits ;The fault structures are the storage and the transport （H2S,hydrocarbons） channels for reducing materials （carbon dusts）.It usually tends to form an oxidation-reduction zone in the surrounding strata of the favorable uranium metallogenic tectonic fracture.The sag slopes provide favorable hydrodynamic conditions for sandstone-type uranium mineralization,and it usually tends to form the uranium ore belts or uranium deposits in the regions of sag edge.In addition,through the methods of detailed analysis,and comparing with the characteristics of airborne radioactivity survey anomaly,gravity and magnetic survey anomaly,the electrical measurement anomaly and the seismic reflection,it is found that the geophysical method can used to describe the basal and sediment （mainly sand stone and mudstone） shapes and analyze the sedimentary facies so as to obtain the metallogenic environment and metallogenic regularities of sandstone-type uranium.