Igneous history of the aubrite parent asteroid - evidence from the Norton County enstatite achondrite
Numerous specimens of the Norton County enstatite achondrite (aubrite) were studied by optical microscopy, electron microprobe, and neutron-activation analysis. Norton County is found to be a fragmental impact breccia, consisting of a clastic matrix made mostly of crushed enstatite, into which are embedded a variety of mineral and lithic clasts of both igneous and impact melt origin. The Norton County precursor materials were igneous rocks, mostly plutonic orthopyroxenites, not grains formed by condensation from the solar nebula. The Mg-silicate-rich aubrite parent body experienced extensive melting and igneous differentiation, causing formation of diverse lithologies including dunites, plutonic orthopyroxenites, plutonic pyroxenites, and plagioclase-silica rocks. The presence of impact melt breccias (the microporphyritic clasts and the diopside-plagioclase-silica clast) of still different compositions further attests to the lithologic diversity of the aubrite parent body. 60 references.
- Research Organization:
- Institute of Physical and Chemical Research, Wako (Japan); New Mexico Univ., Albuquerque (USA)
- OSTI ID:
- 6921001
- Journal Information:
- Meteoritics; (United States), Vol. 23
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
ACHONDRITES
CHEMICAL COMPOSITION
ORIGIN
ACTIVATION ANALYSIS
ASTEROIDS
CRYSTALLIZATION
ENSTATITE
IGNEOUS ROCKS
NEUTRON REACTIONS
OPTICAL MICROSCOPES
PYROXENES
RARE GASES
ALKALINE EARTH METAL COMPOUNDS
BARYON REACTIONS
CHEMICAL ANALYSIS
ELEMENTS
FLUIDS
GASES
HADRON REACTIONS
MAGNESIUM COMPOUNDS
MAGNESIUM SILICATES
METEORITES
MICROSCOPES
MINERALS
NONMETALS
NUCLEAR REACTIONS
NUCLEON REACTIONS
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
ROCKS
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
STONE METEORITES
640107* - Astrophysics & Cosmology- Planetary Phenomena