Lithium isotope fractionation between Li-bearing staurolite, Li-mica and aqueous fluids: An experimental study

Isotope Fractionation Processes of Selected Elements

“…High temperature equilibrium Li isotope fractionations have been investigated experimentally (Wunder et al 2006(Wunder et al , 2007 and theoretically (Kowalski and Jahn 2011). Calculated fractionation factors between staurolite, spodumene, mica and aqueous fluids are in good agreement with experimentally derived fractionation factors.…”

Lithium speciation in aqueous fluids at high P and T studied by ab initio molecular dynamics and consequences for Li-isotope fractionation between minerals and fluids

“…On the contrary, in Li-isotope fractionation experiments between staurolite -fluid (Wunder et al, 2007), all performed at higher pressures of 3.5 GPa, the heavy 7 Li preferentially fractionated into staurolite. Under the assumption that the coordinationdependence dominates the Li-isotope fractionation, i.e.…”

“…Isotopic fractionation experiments between spodumene -fluid (Wunder et al, 2006) and mica -fluid (Wunder et al, 2007) showed T-dependent fractionation with preferential incorporation of 7 Li into the fluid. In both spodumene and mica, Li is found in six-fold coordination.…”

“…By breakdown of OH-bearing minerals during the subduction process, lithium isotope fractionations are produced due to preferential incorporation of 7 Li into expelled fluids relative to most silicates, except for staurolite (Wunder et al, 2007).…”

Protoliths and phase petrology of whiteschists

“…It is, however, unclear to which extent the original d 7 Li and d 11 B of the sediments are preserved in the metamorphic rocks. Experimental data demonstrate that the fluid generally has a higher d 7 Li and d 11 B value than the co-existing mineral (e.g., Wunder et al 2005Wunder et al , 2007Meyer et al 2008), and there is a tendency to lose Li and B with progressive metamorphism (e.g., Leemann and Sisson 1996;Zack et al 2003). Thus, metamorphic rocks are expected to have lower d 7 Li and d 11 B values than their protoliths, an expectation that is apparently supported by the occurrence of high-grade metamorphic rocks with particularly low d 7 Li and d 11 B (e.g., Zack et al 2003).…”