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Complex igneous processes and the formation of the primitive lunar crustal rocksCrystallization of a magma ocean with initial chondritic Ca/Al and REE ratios such as proposed by Taylor and Bence (TB, 1975), is capable of producing the suite of primitive crustal rocks if the magma ocean underwent locally extensive assimilation and mixing in its upper layers as preliminary steps in formation of an anorthositic crust. Lunar anorthosites were the earliest permanent crustal rocks to form the result of multiple cycles of suspension and assimilation of plagioclase in liquids fractionating olivine and pyroxene. There may be two series of Mg-rich cumulate rocks: one which developed as a result of the equilibration of anorthositic crust with the magma ocean; the other which formed in the later stages of the magma ocean during an epoch of magma mixing and ilmenite crystallization. This second series may be related to KREEP genesis. It is noted that crystallization of the magma ocean had two components: a low pressure component which produced a highly fractionated and heterogeneous crust growing downward and a high pressure component which filled in the ocean from the bottom up, mostly with olivine and low-Ca pyroxene.
Document ID
19800039505
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Longhi, J.
(Oregon Univ. Eugene, OR, United States)
Boudreau, A. E.
(Oregon, University Eugene, Ore., United States)
Date Acquired
August 10, 2013
Publication Date
January 1, 1979
Subject Category
Lunar And Planetary Exploration
Meeting Information
Meeting: Lunar and Planetary Science Conference
Location: Houston, TX
Start Date: March 19, 1979
End Date: March 23, 1979
Accession Number
80A23675
Funding Number(s)
CONTRACT_GRANT: NGL-38-003-022
Distribution Limits
Public
Copyright
Other

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