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CaSiO 3 and CaTiO 3 perovskite‐melt partitioning of trace elements: Implications for gross mantle differentiation
Author(s) -
Corgne Alexandre,
Wood Bernard J.
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2001gl014398
Subject(s) - mantle (geology) , lithophile , geology , volatiles , fractionation , partition coefficient , mineralogy , geochemistry , chemistry , partial melting , organic chemistry , chromatography
We report the results of CaSiO 3 perovskite‐melt partitioning experiments conducted at conditions relevant to the uppermost lower mantle. Partition coefficients, measured by LA‐ICPMS, show that CaSiO 3 perovskite has a strong affinity for REE, Y, Th and U, making CaSiO 3 the most likely host for these elements in the lower mantle. Comparison with the low‐pressure analogue CaTiO 3 shows that large ions partition similarly into the Ca‐sites of the two perovskites. Thus CaTiO 3 may be used as a model to investigate the factors controlling the partitioning of many trace ions into CaSiO 3 . Combined fractionation of MgSiO 3 and CaSiO 3 perovskites during an early magma ocean has been suggested as a means of enriching the lower mantle in silica. Our results show, however, that the chondritic upper mantle ratios of refractory lithophile elements would be lost after ∼17% of perovskite fractionation. A large perovskitic layer `hidden' in the lower mantle is therefore improbable.