Degree of equilibration of eucritic pyroxenes and thermal metamorphism of the earliest planetary crust

Journal Article · Sat Jun 01 04:00:00 EDT 1991 · Meteoritics; (United States)

DOI:https://doi.org/10.1111/j.1945-5100.1991.tb01028.x· OSTI ID:5256989

Takeda, Hiroshi; Graham, A L ^[1]

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1. Tokyo, University (Japan) Natural History Museum, London (England)

The pyroxenes in two new monomict eucrites from Antarctica, Yamato 791186 and Yamato 792510, have been studied and compared with those of other Antarctic and non-Antarctic eucrites. The purpose of this study is to identify compositional and textural relationship shown by these pyroxenes which may be used as indicators of the thermal history of the meteorite. An attempt is made, using petrographic and compositional criteria, to distinguish between the initial cooling history and subsequent thermal events. It is suggested that it is possible to identify stages of thermal 'metamorphism' which may be used to indicate the conditions on the surface and crust of the parent body. A picture of the geological setting of the HED (Howardites, Eucrites, Diogenites) parent body is proposed, for which thermal metamorphism by impact heating is an important process. 22 refs.

• OSTI ID: 5256989
• Journal Information: Meteoritics; (United States), Journal Name: Meteoritics; (United States) Vol. 26; ISSN 0026-1114; ISSN MERTA
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANNEALING
ANTARCTIC REGIONS
CHEMICAL COMPOSITION
CRYSTAL STRUCTURE
EARTH CRUST
HEAT TREATMENTS
HEATING
IMPACT SHOCK
METAMORPHISM
METEORITES
MICROSTRUCTURE
MINERALOGY
MINERALS
ORIGIN
OXYGEN COMPOUNDS
PETROGRAPHY
PLANETARY EVOLUTION
POLAR REGIONS
PYROXENES
SILICATES
SILICON COMPOUNDS
SOLAR SYSTEM EVOLUTION