Rôle des facteurs hydrodynamiques dans le contrôle de la formation et de l’emplacement des dépôts d’uranium associés à des discordances: aperçus issus de la modélisation de transport réactif

Location of Uranium‐Rich Brines Determines the Distribution and Grade of Unconformity‐Related Uranium Deposits

“…More details on the numerical modeling approach and the geochemical system can be found in previous publications by Xu et al. (2004, 2011) and Aghbelagh and Yang (2014, 2017).…”

“…Graphite is its main mineral together with muscovite, quartz, chlorite, pyrite, and kaolinite. Compiled from the parameters previously employed in related modeling studies and the physical properties obtained from in‐lab measurements of the Athabasca group sandstone samples (e.g., Aghbelagh & Yang, 2014, 2017; Cui et al., 2012a; King et al., 1988; Li et al., 2016; Raffensperger & Garven, 1995), Table 1 shows the density, porosity, permeability, and thermal conductivity of the four geological units, whereas Tables 2–5 tabulate the initial mineral volume fractions and aqueous component concentrations for each hydrostratigraphic unit. Table 6 shows the chemical parameters for the minerals involved, including the kinetic rate constant at 25°C K 25 (mol/m 2 s), activation energy E a (kJ/mol), and reactive surface area A m (cm 2 /g).…”

“…The rest seeps Note. Based on previous studies by Raffensperger and Garven (1995) and Aghbelagh and Yang (2017).…”

“…In this paper, it is assumed that aqueous methane is produced by dissolving graphite in fault zones at typical ore‐forming brine temperatures, according to reaction : $$$\mathrm{C}+\frac{3}{2}{\mathrm{H}}_{2}\mathrm{O}{\leftrightarrow}\frac{1}{2}{\mathrm{H}}^{+}+\frac{1}{2}{\mathrm{HCO}}_{3}^{-}+\frac{1}{2}{\mathrm{CH}}_{4}^{0}(\mathrm{aq}),$$$ which is then used as a reducing agent to reduce uranium ore (Aghbelagh & Yang, 2014, 2017; Raffensperger & Garven, 1995), following reaction : $$$\mathrm{U}{\mathrm{O}}_{2}^{2+}+\frac{3}{4}{\mathrm{H}}_{2}\mathrm{O}+\frac{1}{4}{\mathrm{C}\mathrm{H}}_{4}^{0}(\mathrm{a}\mathrm{q}){\leftrightarrow}\mathrm{U}{\mathrm{O}}_{2}+\frac{1}{4}\mathrm{H}\mathrm{C}{\mathrm{O}}_{3}^{-}+\frac{9}{4}{\mathrm{H}}^{+}.\quad $$$ …”

Reactive Transport Modeling Applied to Ni Laterite Ore Deposits in New Caledonia: Role of Hydrodynamic Factors and Geological Structures in Ni Mineralization

“…Yet a few coupled geochemical and fluid flow models have been developed to study hydrodynamic impact on locations of deposits in some mineral‐rich terrains in the world. Some examples concern the formation of gold (Zhang et al, ), uranium (Aghbelagh & Yang, ), and Pb/Zn deposits (Hobbs et al, ) and do not concern ultramafic environments. The models are generally studying simple hydrodynamics and restricted by one chemical domain.…”