Application of improved bi-dimensional empirical mode decomposition (BEMD) based on Perona–Malik to identify copper anomaly association in the southwestern Fujian (China)

• BEMD is effective for decomposing geochemical patterns.
• The PM model enhances anomaly edges.
• Anomaly trends obtained by BIMFs–PM and S–A models are consistent.

The bi-dimensional empirical mode decomposition (BEMD) technique based on the kriging envelope interpolation method can smooth the sampling error and improve the robustness of the decomposition. In this study, Cu mineralization related elements (i.e., Zn, Sn, Sb, Pb, Cu, Au, As, Ag, Mo and Cd) were selected to identify geochemical anomalies associated with Cu polymetallic mineralization in southwestern Fujian Province (China) using the hybrid method for integrating bi-intrinsic mode functions (BIMFs) and Perona–Malik (PM). The results show that most of the known Cu deposits occur in or near highly anomalous areas. The results obtained by the hybrid method are consistent with the results obtained by the spectrum–area (S–A) multifractal model, suggesting that the former is a powerful tool to identify geochemical anomalies. Moreover, the hybrid method can be further used to infer geological bodies. For example, in this study, the BIMF3 likely relates to the spatial distribution of Jurassic–Cretaceous Yanshanian formations, which are the likely sources of metals for the formation of Cu deposits.