二连盆地北部玄武岩覆盖区电性结构与铀成矿环境研究

Study on electrical structure and uranium metallogenic environment of basalt-covered area in the northern Erlian Basin

二连盆地砂岩型铀矿集中产出在巴—赛—齐古河谷内。古河谷北部多被玄武岩覆盖,增加了铀矿勘探的难度。根据玄武岩覆盖区的电性特征,优选并开展音频大地电磁测量(AMT),获取了断裂、砂体、玄武岩展布和基底、构造格架等铀成矿信息,为评价区内找矿前景提供深部电性数据支撑。玄武岩覆盖区存在玄武岩盖层、沉积地层和基底三元电性结构。区内有利铀成矿的赛罕组砂体和断裂较为发育,深部热流体可以为铀的叠加成矿提供热源。铀矿勘探需关注近玄武岩盖层的沉积地层的铀聚集。另兼顾铀源条件,建议查明玄武岩覆盖区以NNW走向的断裂展布,为热流体叠加成矿的铀矿勘探提供依据。

Sandstone type uranium deposits in Erlian Basin are concentrated in the Ba-Sai-Qi ancient channel. The northern part of the channel is mostly covered by basalt, which increases the difficulty of uranium exploration. According to the electrical characteristics of the basalt-covered area, the audio frequency magnetotelluric survey(AMT) was optimized and carried out to obtain uranium metallogenic information such as fracture, sand body, basalt distribution, basement, and tectonic framework, providing deep electrical data support for evaluating the prospecting prospect in the area. There are ternary electrical structures-basalt cap, sedimentary strata and basement rock in basalt-covered area. The sand bodies and fractures of Saihan Formation favorable for uranium mineralization are well developed in the area, and the deep thermal fluid can provide heat source for uranium superimposed mineralization. Uranium accumulation in sedimentary strata near basalt caprock should be considered in uranium exploration, and also uranium source conditions. Therefore, it is suggested to find out the NNW-trending fracture distribution in the west of basalt-covered area so as to provide a basis for uranium exploration of hydrothermal superimposed mineralization.