Magnesian anorthosites and associated troctolites and dunite in Apollo 14 breccias

Conference · Thu Nov 15 04:00:00 EST 1984 · JGR, J. Geophys. Res., (Sect.) C:; (United States)

OSTI ID:5822610

Lindstrom, M M; Knapp, S A

Magnesian anorthosite, a new type of pristine lunar highlands rock, has been found in Apollo 14 breccias. It has primitive (high Ca and Mg) silicate mineral compositions, and high and variable REE concentrations. Variations in REE contents can be accounted for by variations in modal abundance of REE-rich apatite. Magnesian anorthosites are associated with troctolites and a dunite with very similar mineral compositions and it is suggested that all crystallized from a differentiated troctolitic intrusion. The origin of the REE-rich apatite is enigmatic. It is unlikely to have crystallized from an igneous liquid in equilibrium with the major minerals in the anorthosite. Possible origins are assimilation of urKREEP or metasomatism by REE-rich fluids. REE-rich alkali anorthosites and gabbronorites are also found and are likely to be related to KREEP basalt magmas. Lunar compositional associations are distributed in a regional rather than global manner.

• Research Organization: Washington Univ., St. Louis, MO
• OSTI ID: 5822610
• Report Number(s): CONF-840385-
• Conference Information: Journal Name: JGR, J. Geophys. Res., (Sect.) C:; (United States) Journal Volume: 89
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALKALINE EARTH METAL COMPOUNDS
ANORTHOSITES
APOLLO PROJECT
CALCIUM COMPOUNDS
CALCIUM SILICATES
CHONDRITES
CRYSTAL STRUCTURE
ELEMENTS
GABBROS
IGNEOUS ROCKS
LUNAR MATERIALS
MAGNESIUM COMPOUNDS
MATERIALS
METALS
METEORITES
MICROSTRUCTURE
ORIGIN
OXYGEN COMPOUNDS
PLUTONIC ROCKS
RARE EARTHS
ROCKS
SILICATES
SILICON COMPOUNDS
STONE METEORITES