  Subsurface fluid flow and solute transport are pivotal in addressing pressing
energy, environmental, and societal challenges, such as geological CO2 storage.
Basaltic rocks have gained prominence as suitable geological substrates for
injecting substantial CO2 volumes and carbon mineralization, driven by their
widespread occurrence, high concentrations of cation-rich silicate minerals,
reported fast mineralization rate, and favorable characteristics such as
porosity, permeability, and injectivity. The mineralization process within
basaltic rocks is intricately linked, involving the dissolution of silicate
minerals and the subsequent precipitation of carbonate minerals. Columnar flow
and batch surface growth experiments revealed the spontaneous formation of a
limited number of large crystals at various locations, rationalized by the
overarching influence of probabilistic mineral nucleation. Experiments with
CO2-acidified brine versus freshwater prove to be more challenging regarding
the sweet spots for heavy carbon mineralization due to clay formation on the
surface, particularly smectites. Despite numerical predictions suggesting the
formation of MgFeCa-carbonates in CO2-basalt interactions at higher
temperatures, our laboratory findings primarily indicated the growth of calcium
carbonates. The experimental and numerical outcomes highlight the necessity of
a probabilistic approach for accurately modeling reaction kinetics, crystal
growth distribution, and the dynamic interplay between reactive flow,
geochemical reactions, mineral carbonation, and geometry alteration.
