Calcium isotopic ratios and rare earth element abundances in refractory inclusions from the Allende CV3 chondrite

摘要: Abstract Refractory inclusions in primitive meteorites are the oldest objects formed Solar System. They exhibit large mass-dependent isotopic effects many elements, including Si, Mg and Ca, indicative of their complex origin. We report data for both (δ) mass-independent (e) Ca effects, rare earth element (REE) abundances six refractory from Allende CV3 meteorite. Our reveal these inclusions, with δ 44/40 ranging −5.60 to +0.35 (relative NIST SRM 915a), which significantly lower than that bulk silicate Earth (δ Ca = 1.05 ± 0.04). Importantly, is correlated REE patterns: Group II patterns have lighter isotope compositions compared those I patterns. Specifically, studied form negative 44 Ca/ 40 Ca–Tm/Er Ca–Nd/Er trends, implying segregation up 3% an ultrarefractory evaporation residue a chondritic reservoir prior formation inclusions. This would be characterized by high low Tm/Er Nd/Er. At 2 σ levels ±0.5 ±1.5 e 40/44 43/44 respectively, show no detectable or 43 anomalies relative terrestrial standards. However, five out do 48 excess several e-units, clearly resolvable