The formation of mineral deposits is generally accompanied by the superposition or transformation of different geological events, and involving varying sources (shallow and deep) of ore-forming materials. The geological significance of these ore-forming events and their corresponding geochemical fields have various implications for mineral exploration. Multistage superimposed mineralization typically manifests as a complex superimposed field comprising multiple sources in geochemical contexts. Effectively decomposing the ‘multi-source complex superimposed field’ and establishing the coupling between the geochemical field and its corresponding ore-forming geological events can greatly enhance the accuracy of geochemical evaluation in exploration. Based on this concept, this study utilized the C-A multifractal model to analyze hydrocarbon-mercury comprehensive gas measurement data from soil medium in the Woxi gold mining area of Hunan. By extensively exploring the correlations of data at different scales and combining the mineralization patterns of gold deposits in the study area, the study further investigated the mineralization mechanisms of various types of “superimposed fields” and conducted an assessment of deep-seated mineral exploration potential. The results indicate that: ① The study area exhibits two characteristic multifractal patterns of soil geochemical anomalies, formed by fitting either two (termed Model Ⅰ) or three (termed Model II) straight-line segments, respectively. This multifractal model suggests the possibility of two periods of overlapping mineralization in the study area. ② Examination of correlations between mineralization elements (Au), organic hydrocarbons (CH₄, C₂H₆, etc.), and other chemical elements in the different scaling regions of Models I and II revealed that both showed two distinct superimposed geochemical anomalies, formed by different mineralization processes. The “syngenetic superimposed anomaly” represents regional mineralization, in which shallow-source fluids (metamorphic fluids, atmospheric precipitation, etc.) only bring mineralized materials from ore-forming strata to participate in Au mineralization. This type of anomaly, limited by the source of mineralization materials, may form gold points or small gold deposits, with correspondingly low potential for discovering large deposits. The “deep-source superimposed anomaly”, on the other hand, is influenced by plate collisions, dispersion, or the upwelling of mantle heat columns and the disturbance of deep large fractures. These processed facilitate the migration of mantle fluids from depth, and their evolution through multi-level fluid mixing, which brings a substantial amount of deep ore-forming materials to further superimpose mineralization on the “syngenetic superimposed anomaly”, thus presenting considerable potential for deep mineral discovery. The results align closely with extensive engineering validation, indicating that the decomposition of complex geochemically superimposed fields based on the C-A multifractal model has achieved better application results, providing new research ideas and methods for evaluating the potential of deep mineral exploration in geochemistry.