The redox dependence of titanium isotope fractionation in synthetic Ti-rich lunar melts

Abstract Equilibria between Ti oxides and silicate melt lead to isotope fractionation in terrestrial samples, with isotopically light heavy coexisting melt. However, while is mostly tetravalent around 10% of the overall trivalent at f O 2 relevant lunar magmatism (~ IW-1). The different valences could additionally influence stable during petrogenesis basalts an unknown extent. We performed experimental approach using gas mixing furnaces investigate effect oxide formation on mare basalt petrogenesis. Two identical bulk compositions were equilibrated simultaneously each experiment guarantee comparability. One was investigated EPMA characterize petrology run products, whereas second crushed, fabricated phases (i.e., oxides, silicates glass) handpicked, separated digested. An aliquot sample mixed a double-spike, before from matrix interfering elements modified HFSE chemistry. Our study shows -dependent within seven samples air IW-1, especially ? 49 armalcolite-melt armalcolite-orthopyroxene become more fractionated oxidized reduced conditions (? 0.092 ± 0.028- ? 0.200 0.033 ‰ 0.089 0.027- 0.250 0.049 ‰, respectively), orthopyroxene-melt only minor 0.002 0.017-0.050 0.025 ‰). results this show that expected be redox dependent mineral-melt as commonly determined for may not directly applied setting. This important evaluation resulting magmatism, which takes place under reducing compared magmatism.