2011 Honorary Lecturer

Pacific South

Richard Lane

Geoscience Australia - Canberra, Australia

Building on 3D geological knowledge through gravity and magnetic modeling workflows at regional to local scales

Abstract

In many different projects, from petroleum basin studies through regional geological investigations to evaluation of local-scale mineral exploration prospects, we are looking to use gravity and magnetic data to help build confidence in our knowledge of subsurface 3D geological architecture. We seek one or more geological models that are consistent with a diverse set of observations that include: geological observations, measurements of the rock properties, and gravity and magnetic data.

Using various methods, and with wildly varying degrees of factual underpinnings, we can produce an initial vision of the 3D geological configuration, estimates of the bulk properties of the materials within each of the geological units, and a description of the degree to which these should be relied upon. By applying different tools and methodologies, we can perform forward and inverse modeling of the potential field data, constrained by initial confidence in the geological scenario. In each case, we examine the results and decide whether it confirms the input model or whether unconstrained portions of the map or poorly known property values need to be revised. Recent advances on many fronts, from data acquisition systems, 3D software tools, data interchange standards, and high-performance computing environments, have re-invigorated potential field modeling and made this an exciting activity to be involved in.