Impact of rock heterogeneities at the Basin/Basement interface on the alteration halo geometry of unconformity-related Athabasca uranium deposits

@inproceedings{hidalgo:hal-05247148,
 abstract = {Canada’s Athabasca Basin hosts the world’s highest-grade uranium deposits. These exceptional deposits are linked to hydrothermal brine circulation at the unconformity between this sedimentary basin and its meta- morphic basement. The emplacement and geometry of “unconformity related uranium deposits” are mainly controlled by the fluid circulations and therefore depend of the hydraulic conductivity heterogeneities of the rocks. Impact of the different parameters that modify the hydraulic conductivity of the rocks have to be tested to assess their role in the formation of uranium deposits. The present study investigates the various rocks heterogeneity factors that control hydraulic conductivity fluctuations and hence the setting and geom- etry of uranium deposits. The use of synthetic geometric models based on fast marching methods allows to test different alteration front propagation scenarios in various sedimentary environments. Lithological and petrophysical characteristics of models are backed up by new data acquired on samples from Athabasca Basin. Three main factors have been studied: (i) fault maturity and intensity of fracturation associated; (ii) the addition of conglomeratic levels in the basin; (iii) the presence of a cap rock at the unconformity. This investigation highlights the importance of considering rock heterogeneities in deposit formation, by exploring various scenarios of deposit formation. Fault maturity and the presence of conglomerates affect the geometry of alteration halos and the distribution of mineralization in a basin. A basal conglomerate level in the basin may act as a cap, while a paleoweathering level in the basement may act as a reservoir by draining basement fluids. The integration of basin and basement heterogeneities makes it possible to develop models that are more representative of the geological history of the Athabasca Basin, thereby improving our understanding of deposit-forming conditions.},
 address = {Nancy, France},
 author = {Hidalgo, Virgile and Marchal, Paul and Milesi, Ga{\'e}tan and Guermonprez, Dorian and Scibek, Jacek and Mercadier, J.},
 booktitle = {{RING meeting 2024}},
 hal_id = {hal-05247148},
 hal_version = {v1},
 month = {September},
 pdf = {https://hal.science/hal-05247148v1/file/Virgile_v2_paper.pdf},
 title = {{Impact of rock heterogeneities at the Basin/Basement interface on the alteration halo geometry of unconformity-related Athabasca uranium deposits}},
 url = {https://hal.science/hal-05247148},
 year = {2024}
}