Driving mineral dissolution studies towards new directions: applications to geothermal concerns

Abstract

The chemical weathering of rocks represents a fundamental step in the geochemical cycle of many elements. Interactions between aqueous fluids and rock-forming minerals play a central role in many major engineering, environmental, and geological processes. Whether it determines the rates of soil formation (Godderis et al., 2006), soil fertility and nutrient availability (White and Brantley, 1995), CO2 uptake and its impact on climate change (Beaulieu et al., 2012), durability of radioactive waste confinement glasses (Frugier et al., 2008) or geological sequestration of CO2 (Knauss et al., 2005), the same bottom-up strategy has been so far applied for predicting the long term evolution of fluid-rock interactions. This strategy relies on (i) the experimental determination of the kinetic rate laws governing the dissolution of silicate minerals, which is based on experiments performed on freshly crushed single minerals immersed in synthetic solutions, and (ii) the implementation of such laws into reactive transport codes. Nowadays, this methodology represents a standard approach in hydro- and biogeochemistry for predicting the chemical weathering rates of rocks.