Modelling lake sediment geochemical distribution using principal component, indicator kriging and multifractal power-spectrum analysis: a case study from Gowganda, Ontario

Combined geostatistical and multifractal power-spectrum modelling of geochemical distributions can provide suitable indicators of metal dispersion, and is capable of analysing complex problems for targeting potential areas for mineral exploration. A case study analysing lake sediment geochemical data for the Gowganda area is presented and development of the methodology for spatial analysis of the data is described. The Gowganda-Cobalt area of northeastern Ontario is a textbook example of Co, Ag-Co vein-type deposit, which by 1984 had yielded one-half billion ounces of Ag. The area is also known for shear-zone-hosted Au mineralization. This paper uses the spatial and geometric distribution of lake sediment data to discriminate geochemical anomalies from background values. The application of two geostatistical techniques (spatial principal component analysis and indicator kriging) allows the estimation of geochemical distributions by utilizing their statistical and spatial properties. The newly developed multifractal power-spectrum method additionally allows for the geochemical distributions to be modelled by their multifractal Fourier-transformed power-spectrum characteristics. Verification of the estimates produced by these techniques has been enabled through spatial analysis of bedrock geology and mineral deposit occurrences in the area.