Continental-scale geochemical surveys and mineral prospectivity: Comparison of a trivariate and a multivariate approach

The National Geochemical Survey of Australia (NGSA) provides an internally consistent, state-of-the-art, continental-scale geochemical dataset that can be used to assess areas of Australia more elevated in commodity metals and/or pathfinder elements than others. But do regions elevated in such elements correspond to known mineralized provinces, and what is the best method for detecting and thus potentially predicting those? Here, using base metal associations as an example, I compare a trivariate rank-based index and a multivariate-based Principal Component Analysis method. The analysis suggests that the simpler rank-based index better discriminates catchments endowed with known base metal mineralization from barren ones and could be used as a first-pass prospectivity tool. • Prospectivity analysis typically uses a range of often complex statistical tools. • Prospectivity for base metal deposits in Australia uses NGSA aqua regia data. • Average Ag, Pb, Zn rank-based method contrasted to PCA clr-based approach. • KS test shows rank-based method better identifies mineralized catchments. • Rank statistics are compositionally compliant yet underused in exploration.