四川理塘海子山地区放射性地球物理特征

为研究四川理塘海子山地区放射性地球物理特征及铀成矿地质背景和成矿条件,在区内开展了地面伽马总量面积测量和地质-伽马能谱综合剖面测量。通过地面伽马总量面积测量,了解了海子山地区的伽马放射性背景,分析了其放射性特征; 通过地质-伽马能谱综合剖面测量,初步判定了研究区内燕山晚期花岗岩的放射性异常性质,分析了各主要地层岩石的放射性核素含量特征。研究表明: 区内出露的燕山晚期花岗岩有较高的伽马总量背景值,且伽马总量异常的展布与燕山晚期花岗岩体的分布特征基本一致; 花岗岩体的铀含量背景值较高,显示了区内良好的铀源条件; 研究区外围西侧有与NE向的断裂破碎带有关的查清卡温泉异常点,地表泉华具有极高的伽马总量测量值,且伽马能谱测量显示其为铀、钍混合异常点。根据查清卡温泉异常点的地质和放射性特征,并结合研究区铀成矿地质背景和成矿条件,初步判定本区铀源可能为深部含铀流体或铀富集在深部燕山晚期花岗岩体中,铀元素通过泉水迁移至地表沉淀富集,提供了下一步铀矿找矿方向。

Radioactive geophysical features of Haizishan area in Litang of Sichuan Province

In order to investigate the radioactive geophysical features, uranium metallogenetic geological setting and metallogenetic conditions at Haizishan area, the ground total gamma survey and geology-gamma spectrometric profile survey were conducted. The radioactive background of Haizishan area was preliminarily cognized through the ground total gamma survey and the radioactive features were identified. The anomaly properties of Late Yanshan granites were roughly confirmed through geology - gamma spectrometric profile survey, and the detailed statistical analysis was done for radionuclide contents of each major lithostratigraphy. The results show that Late Yanshan granites in this area have higher total gamma background value, and the distribution of total gamma anomaly is almost consistent with Late Yanshan granites. The uranium background value of the granites is higher, showing the uranium sources are favorable in this area. There is Chaqingka hot-spring anomaly in the western periphery of Haizishan area, which is in connection with the northwest fault. The sinter on the ground has very high total gamma measurement value, and the uranium - thorium anomaly occurrence is shown through gamma spectrometric survey. According to the geological and radiometric properties of Chaqingka hot-spring anomaly, combined with the uranium metallogenetic geological setting and metallogenetic conditions in the area, the authors identified that the potential source of uranium is bearing fluids containing uranium or the uranium is likely to be abundant in deep Late Yanshan granites. The uranium is migrated to deposit and enrich at the surface, which provides a prospecting target for further uranium exploration.