Joint stochastic modeling of hydrothermal ore deposits and their control structures
A seminar on hydrothermal deposit modelling will be presented by Paul Marchal from GéoRessources, Université de Lorraine.
Abstract
Many hydrothermal mineral deposits are characterized by sub-concentric envelopes of alteration facies. These alteration halos, which are physical or chemical anomalies, generally have a larger spatial footprint than the targeted mineralization and are therefore often used as prospecting indicators. Alteration also affects the rock’s mechanical behavior and mineral
composition, and therefore has an impact on mine planning (extraction, ore processing).
We propose a new joint approach to model these alteration halos and their geological controls. In fact, the circulation of hydrothermal fluids, which cause alteration, is primarily driven by geological objects such as fault systems or regional unconformities, as well as by smaller-scale objects such as fracture networks. Our implicit modeling methodology relies on the use of a multi-component structural skeleton, which then supports an alteration potential field. Stochastic modification of the structural skeleton’s components via a Metropolis-Hastings algorithm enables to generate scenarios of halo geometries and control structures, which not only respect the input data, but also reproduce the variability of data interpretation.
