Exploratory data analysis and singularity mapping in geochemical anomaly identification in Karamay, Xinjiang, China

Abstract Hatu and Baogutu are two typical gold deposits in the study area. Hatu gold deposit is associated with magmatism and controlled by regional-scale faults; mineralisation mainly occurs within hydrothermally altered felsic rocks and quartz veins. In the west region of the Hatu mining area, Cu, Ag, As and Sb are present in high concentrations in carbon tuffaceous shale. Baogutu gold deposit is associated with the evolution of felsic magmas, and the porphyry copper-gold mineralisation and copper-gold ore body dominated by sulphide were formed in the rock or near the contract zone in the faults, respectively. The ore-forming elements include Au, As and Sb. In this study, exploratory data analysis (EDA) and singularity mapping (SM) techniques were applied to identify geochemical anomalies caused by Au-related mineralisation according to stream sediment geochemical data set in Karamay mineral district, northwestern China. Silver, As, Au and Sb were chosen as indicator elements. The results show that EDA could not well identify weak anomalies within the strong variance of the background, while SM can recognise effectively weak anomalies, and quantify the properties of enrichment caused by mineralisation. The results obtained by SM demonstrated that the anomalies are closely associated with the known Au deposits in the study area. The anomalous areas delineated by the SM have potential for follow-up mineral exploration. In addition, the results document that Ag, As, Au and Sb may be reliable indicator elements for Au-related mineralisation in the study area.