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Partitioning in REE-saturating minerals - Theory, experiment, and modelling of whitlockite, apatite, and evolution of lunar residual magmasCompositions, including REEs determined by ion microprobe, of apatite and whitlockite in lunar rock assemblages rich in incompatible trace elements, are presented. Concentrations of REEs in lunar whitlockites are high, ranging from about 1.2 to 2.1 REEs (lanthanides + Y) per 56 oxygens. This slightly exceeds the level of two REE atoms per 56 oxygens at which the dominant substitution theoretically becomes saturated. This saturation effect leads to whitlockite REE(3+) D values at typical lunar whitlockite REE concentrations which are 30-40 percent lower than the D values at low concentrations. The halogen-to-phosphorous ratio in lunar melts is a key factor determining the REE distribution with crystalline assemblages. As long as P and REE concentrations of melts are in KREEP-like proportions, one or both of the phosphates will saturate in melts at similar REE concentrations.
Document ID
19940033478
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Jolliff, Bradley L.
(NASA Lyndon B. Johnson Space Center Houston, TX, United States)
Haskin, Larry A.
(NASA Lyndon B. Johnson Space Center Houston, TX, United States)
Colson, Russell O.
(NASA Lyndon B. Johnson Space Center Houston, TX, United States)
Wadhwa, Meenakshi
(Washington Univ. Saint Louis, MO, United States)
Date Acquired
August 16, 2013
Publication Date
August 1, 1993
Publication Information
Publication: Geochimica et Cosmochimica Acta
Volume: 57
Issue: 16
ISSN: 0016-7037
Subject Category
Lunar And Planetary Exploration
Accession Number
94A10133
Funding Number(s)
CONTRACT_GRANT: NAG9-56
CONTRACT_GRANT: NAG9-55
Distribution Limits
Public
Copyright
Other

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