Predicting Archaean volcanogenic massive sulphide deposit potential from lithogeochemistry: application to the Abitibi Greenstone Belt
Archaean greenstone belts are prime exploration targets for volcanogenic massive sulphide deposits and the use of lithogeochemistry plays an important role in detecting and mapping hydrothermal alteration zones and in recognizing the massive sulphide potential of volcanic assemblages. This study reviews the state of existing lithogeochemical databases and the use of new geochemical analyses for the identification of alteration associated with massive sulphide deposits. This paper also provides a new methodology for the prediction of missing values in geochemical compositions. Through the application of statistical methods, combined sets of lithogeochemical data can be used to create predictive maps of prospective massive sulphide successions. Predictive maps are created through the use of multivariate statistical methods, lithogeochemical alteration indices and normative minerals from which areas of multi-element enrichment and depletion are defined. These indices, when combined in an exploration programme, are potentially useful for massive sulphide discovery. Additionally, the use of rare earth elements can be used to characterize differences in the various supracrustal assemblages and provide a better regional understanding of potential metal endowment.