“…Ni enrichment in the weathered products mainly results from adsorption and Mg-Fe substitution processes (Butt and Cluzel, 2013). The sorption mechanism onto soil or mineral particles has been studied for several isotope systems (Si, Fe, Zn, Cu, Mo, Cd) and has been shown to lead to contrasting fractionation in terms of sign and magnitude (Balistrieri et al, 2008;Delstanche et al, 2009;Goldberg et al, 2009;Mikutta et al, 2009;Wasylenki et al, 2014). In the case of Ni, Wasylenki et al (2015) recently performed experimental adsorption and co-precipitation of dissolved Ni onto Fe-oxyhydroxides and they identified an equilibrium isotope effect leading to the preferential adsorption of light Ni isotopes onto the solid phase with a separation factor ( 60 Ni dissolved-sorbed ) of 0.35 ± 0.10h (1SD).…”