Isotope fractionation in silicate melts

Viscosity models for silicate melts

Rheology of silicates (melts or super cooled as glasses) is one of the most important fields to mankind, as geological activity largely influences life. In this paper, unifying empirical models for the Non-Newtonian shear viscosity and the extensional viscosity are proposed. The models have only one parameter, the zero shear viscosity (the Newtonian plateau), and are valid for a vide range of c...

Isotope Effects, Isotope Separation and Isotope Fractionation

Silicon Isotope Fractionation between Silicate and Metal from an Enstatite Meteorite: Implications for Earth’s Core Formation

Introduction: The presence and amount of Si in Earth's core has important implications for models of the processes and chemistry of core segregation. A metal core containing 5 to 7 wt. % Si can be produced when assuming continuous accretion and equili-bration along the silicate liquidus terminating at ~35 GPa and ~3,000 K, and with a concomitant increase in fO 2 from 4 to 2 log units below IW [...

Stable isotope fractionation by thermal diffusion through partially molten wet and dry silicate rocks

Water plays a fundamental role in affecting geochemical transport and physical properties of magmas. Here we show the previously undocumented behavior of water within partially molten silicate resting in a temperature gradient, producing O, Li and H isotope redistribution by thermal diffusion leading to enrichment of light isotopes at the hot end of the gradient. After weeks to months, fully mo...

Silver Isotope Fractionation in Chondrites

I n t r o d u c t i o n : The study of Ag isotopic compositions is of particular interest because of the extinct radionuclide Pd, which decays to Ag with a half-life of 6.5 Myrs. This chronometer has been successfully applied to unravel formation and differentiation processes of iron meteorites [1-3]. Compared to the early measurements by TIMS, the use of multi-collector inductively coupled pla...