The exploration industry is moving broadly in unison toward the use of increasingly more rigorous, quantitative, and consistent techniques for assessing exploration risk, a movement facilitated in part by the equally widespread and parallel effort to compile and maintain large, globally comprehensive, historical/ technical exploration databases. Probabilistic models of a prospect's chance of succeeding (or failing) are constructed routinely now, in part on the basis of various geologic and geophysical data interpretation inputs to the exploration-risk model. As this note will discuss, the geologic integration of gravity and magnetic data has a definite impact on the evaluation of certain of the exploration-risk model parameters.
The geologic integration of gravity and magnetic data can be used to reduce risk at two key stages of the exploration process. The first stage, often referred to as basin reconnaissance, is the role automatically relegated by most explorers to gravity and magnetic methods. Contrary to this widespread notion, however, gravity and magnetic methods are equally effective for reducing risk at the more local scale typified by the prospect itself. In cases in which the application of gravity and magnetic analysis negatively impacts a prospect's viability, valuable exploration resources can be redirected at finding different and, it is hoped, more economic prospects.
This short philosophical note will summarize some of the chief ways in which risk is reduced by an exploration philosophy embracing the use of gravity and magnetic methods during the two main stages of the exploration process.