Speaker: Paul Marchal

Date: Thursday 23rd of March 2023, 1:15pm.

Abstract:

When modelling hydrothermal deposits, it is critical to consider the interrelationship between fluid flows, tectonic structures, such as faults, and the initial petrophysical characteristics of the rocks. This is essential to improve current modelling processes, which are mainly based on classical deterministic interpolation methods, by incorporating geological knowledge within the modelling approach. This allows a better understanding of orebodies genetic processes and thus help the planning of exploration campaigns, as characterizing altered zone geometry is often a proxy for targeting ore zones in several types of deposits. It also improves the mineral resources of deposits evaluation for mining purposes. The key idea is to translate the hypothetical genetic link between faults, stratigraphic contacts, and fluid sources on the one hand, and the geometry & shape of altered rocks halos on the other, into the modelling approach. We choose to extend the skeleton-based approach, developed by [Henrion et al., 2010] who models karst conduits as an implicit distance function to a structural skeleton, which is perturbed by a data-constrained disturbance field, to incorporate and assess uncertainties. Moreover, based on the work of [Rongier et al., 2014], we wants to incorporate anisotropic behaviour of rocks by customizing this implicit distance field using petrophysical data, such as permeability. Then, given the sparse nature of drillholes datasets, we suggest that generating unknown structural elements between data is essential to better assess uncertainties related to halos’ shapes. This works develops these methodologies to model genetically–related concentric alteration & mineralization halos related to hydrothermal processes such as Unconformity-related uranium deposits of the Athabasca.