Orientation hydrogeochemical survey of the Liudaogou Cu-Mo mineralized zone in a basalt-covered area, northeastern China

Abstract

A hydrogeochemical orientation survey in a basalt-covered area in northeastern China was carried out in order to investigate concealed metallic mineralization under thick basalt cover by hydrogeo-chemical procedures. In this presentation, the main results of the investigation around a Cu-Mo mineralized zone in a basalt-covered area are described. Discussions focus on: 1, the distribution of the principal indicator elements in the stream and spring waters; 2. the migration ability of the main indicator elements in the surficial environment; 3. geochemical characteristics of waters in different geological units of the area; 4. the stability and persistence of the hydrogeochemical patterns of the known deposits and 5. the influence of basalt components on the ore-related hydrogeochemical anomalies and the procedures to eliminate this influence. It has been noted that Mo and SO 4 can be used directly as indicators of Cu-Mo mineralization in the basalt-covered area. In the case of other common indicator elements of sulfide deposits such as Cu and Zi, it is difficult or impossible to discriminate ore-related hydrogeochemical anomalies from background contents related to basalt. However, Cu/Ni and Zn/Ni ratios have been successfully used to eliminate the basalt influence and enhance the ore-related hydrogeochemical anomalies. The stability of the ore-related hydrogeochemical anomalies during a three-week sampling period and the persistence of the hydrogeochemical patterns in different years indicates the effectiveness of water sampling during the dry season in the area. On this basis, it is concluded hydrogeochemical exploration can be used as a major regional exploration method for exploring for concealed metallic mineralization in the basalt-covered areas in northeastern China.