Mapping geochemical anomalies by accounting for the uncertainty of mineralization-related elemental associations

Abstract. Geochemical mapping is a fundamental tool for elucidating the distribution and behaviour of economically significant elements and providing valuable insights into geological processes. Nevertheless, the quantification of uncertainty associated with geochemical mapping has only recently become a subject of widespread concern. This study presents a procedure that primarily consists of the determination of homogeneous clusters, the recognition of elemental associations for each cluster, and the identification of geochemical anomalies, with the aim of accounting for the uncertainty of elemental association in geochemical mapping. To illustrate and validate the procedure, a case study was conducted wherein geochemical stream-sediment samples from the northwestern region of the province of Sichuan, China, were processed to map anomalies associated with disseminated gold mineralization. The results indicate that (1) the representativeness of elemental association for the underlying geological process is an important source of uncertainty for geochemical mapping; (2) the procedure presented here is effective in addressing the uncertainty of elemental associations in geochemical mapping; and (3) the study area can be classified into two clusters, each characterized by unique elemental associations that align well with the distribution of Paleozoic and Triassic lithological units, respectively. Furthermore, the region still holds great potential for the discovery of gold deposits, particularly in areas proximal to known mineralization sites.