Integrated Interpolation Methods for Geophysical Data: Applications to Mineral Exploration

Geophysical data are used routinely in mineral exploration to delineate the geology of an area.Because geophysical attributes are sparsely sampled, interpolation methods are used to gridthe individual sets of data. Whereas traditional techniques interpolate constituent attributes ofinterest independently, frequently resulting in simplistic geological models, alternativetechniques interpolate by integrating secondary data sets collected in the explored area. Traditionaltechniques include minimum curvature and ordinary kriging. Alternative integrated interpolationtechniques include standardized ordinary cokriging, collocated cokriging, and kriging withexternal drift. Application of these techniques to a specific exploration area in interpolatinggravity measurements (primary data) using weakly correlated aeromagnetics (secondary data)suggests that when gravity is well sampled, all techniques generate similar results. However,when gravity is undersampled, the secondary data can contribute substantially to identifyinggeophysical anomalies. Considering the high cost of geophysical data collection, this observationcan make geophysical data collection more efficient and cost effective. The case studyshows how, in the absence of a strong correlation, cokriging varieties tend to produce mapssimilar to those generated by traditional techniques. Kriging with external drift is shown togenerate a gravity map reproducing all gravity anomalies. The technique produces excellentresults when features identified in the secondary data need to be reflected in the map of theprimary data.