Isotope velocimetry: Experimental and theoretical demonstration of the potential importance of gas flow for isotope fractionation during evaporation of protoplanetary material

We use new experiments and a theoretical analysis of the results to show that the isotopic fractionation associated with laser-heating aerodynamic levitation experiments is consistent with the velocity of flowing gas as the primary control on the fractionation. The new Fe and Mg isotope data are well explained where the gas is treated as a low-viscosity fluid that flows around the molten spheres with high Reynolds numbers and minimal drag. A relationship between the ratio of headwind velocity to thermal velocity and saturation is obtained on the basis of this analysis. The recognition that it is the ratio of flow velocity to thermal velocity that controls fractionation allows for extrapolation to other environments in which molten rock encounters gas with appreciable headwinds. In this way, in some circumstances, the degree of isotope fractionation attending evaporation is as much a velocimeter as it is a barometer. BioRad 10 mL columns with 2 mL of AG50W-X8 resin in 200-400 mesh hydrogen column separate Ca from Mg to avoid any interference from 48 Ca ++ on 24 Mg + . The second column is to remove alkali (Na and Al. Before the of Milli-Q of HCl, Milli-Q and with mL of mL sample volumes in ∼ 10 N HCl on the 30-50 of Mg. with 5 mL of 10 N HCl, leaving Ca on the Ca The in ∼ 10 N plate 120 o and redissolved 0.5-1 0.5 N HCl for the second column procedure. BioRad 10 mL columns filled with 2 mL of AG50W-X8 resin in 200-400 mesh hydrogen form were used for the second purification step. The resin was washed with 10 mL of Milli-Q water, 10 mL of 0.5 N HCl, 15 mL of 6 N HCl, 10 mL of Milli-Q and 15 mL of 6 N HCl, by with 10 mL of 0.5 After 0.5 to 1 mL sample in N HCl, Cr and alkali elements (Na and eluted with 34 mL of 0.5 N HCl. 7 mL 2 mL Milli-Q eluted HCl.