Thulium anomalies and rare earth element patterns in meteorites and Earth: Nebular fractionation and the nugget effect
N. Dauphas, A. Pourmand
Geochimica et Cosmochimica Acta
in press, arXiv:1503.08708
Update (11 April):
Terrestrial rocks and samples from ordinary and enstatite chondrites display negative Tm anomalies of ~-4.5 % relative to ca chondrites. In contrast, CM, CO and CV (except Allende) show no significant Tm anomalies. Allende CV chondrite shows large excess Tm (~+10 %). These anomalies are similar to those found in group II refractory inclusions in meteorites but of much smaller magnitude. The presence of Tm anomalies in meteorites and terrestrial rocks suggests that either (i) the material in the inner part of the solar system was formed from a gas reservoir that had been depleted in refractory dust and carried positive Tm anomalies or (ii) CI chondrites are enriched in refractory dust and are not representative of solar composition for refractory elements. The observed Tm anomalies in ordinary and enstatite chondrites and terrestrial rocks, relative to carbonaceous chondrites, indicate that material akin to carbonaceous chondrites must have represented a small fraction of the constituents of the Earth.