Spatial characteristics of geochemical patterns related to Fe mineralization in the southwestern Fujian province (China)

• Variograms were used to explore the spatial characteristics of geochemical patterns.
• A fractal model was used to describe complexities of mineralization.
• Iron mineralization was identified using local spatial autocorrelation and PCA.

In this paper, geostatistical, fractal, and spatial autocorrelation methods were applied to investigate the spatial characteristics of stream sediment geochemical data of Cu, Mn, Pb, Zn, and Fe2O3 collected from southwestern Fujian province of China. The spatial variograms showed that these elements are spatially correlated up to 40 km, which is consistent with ranges of positive spatial autocorrelation computed using spatial correlograms based on Moran's I. The coefficients of variation of these elements are less than 0.25, exhibiting strong spatial dependence. All the five elements have fractal dimensions of around 2.9 and showed similar spatial complexities. These results indicate that the spatial characteristics of each element were controlled by similar geological factors or processes. The integrated map of local Moran's I for these five elements, produced by principal components analysis, was decomposed into two components using the spectrum–area fractal model: a background map and an anomaly map, and the latter showed that the areas linked to high values have a strong spatial correlation with the known skarn-type Fe deposits. These results suggest that geostatistical, fractal, and spatial autocorrelation methods are helpful for identifying potential target areas for Fe mineral exploration in the study area.