A case study on geochemical anomaly identification through principal components analysis supplementary projection

Abstract

Based on a case study in which a single geochemical anomaly was located in the vicinity of an abandoned mine in Central Portugal, a recursive methodology for anomaly/background separation was developed. This methodology relies on the supplementary projection of each of the samples taken from a subset of [`]anomaly candidates' onto the axes provided by Principal Components Analysis of the background subset. The concept of [`]anomaly intensity', defined by the average of the distances from the original to the supplementary projections, is the basis for final anomaly identification.