Geologists and geophysicists: getting them on the same planet

Abstract

The results of new detailed airborne geophysical surveys over Victoria have been lauded by industry as being a great incentive to increase mineral exploration in the State. These data become especially useful when combined with new semi-detailed geological mapping. The Geological Survey of Victoria has now developed a new methodology to integrate geological mapping with the interpretation of the geophysical data to produce a single composite understanding of the rocks and their relationships. It has required a reappraisal of the way geologists and geophysicists map, both together and separately, and additional training to make the process work. Sufficiently detailed data acquired prior to the geological mapping allows a fully integrated interpretation, using the available geophysical and geological data, to produce maps that reflect both geological and geophysical reality. Previously, geologists and geophysicists worked in partial or complete isolation. Too often geophysicists gave geologists lineament or line maps that bore little resemblance to geological reality, lacked credibility and were almost immediately discarded by geologists as being "unhelpful". The new process requires geologists and geophysicists to work as a team to reconcile all the geophysical and geological observations to produce an accurate, integrated geological map. It demands that the geologist understands the geophysical responses and the geophysicist understands the geology. Both need to acknowledge the limitations inherent in each method. Presenting the results provides a further series of challenges to the mappers, interpreters, managers and cartographers. We have also yet to integrate the mineralisation history into this mapping process. Meeting these challenges to produce a full and accurate understanding of the geology and geophysics, rather than of one or the other, is essential to ensure increased exploration success.