Summary
The Brachina meteorite is the type specimen of the brachinites class of the asteroidal achondrites.
| Brachina meteorite | |
|---|---|
| Type | Primitive achondrite |
| Class | Asteroidal achondrite |
| Group | Brachinite |
| Composition | olivine, plagioclase, clinopyroxene, iron-sulfide, chromite, chlorapatite, pentlandite, meteoric iron, melt inclusions |
| Country | Australia |
| Region | South Australia |
| Coordinates | 31°18′00″S 138°23′00″E / 31.300000°S 138.383333°E |
| Observed fall | No |
| Found date | 26 May 1974 |
| TKW | 202.85 grams (7.155 oz) (2 fragments) |
Naming and discovery edit
The meteorite is named after Brachina in South Australia. Two fragments (total 200 g) were found by B.M. Eves at 31°18′00″S 138°23′00″E / 31.300000°S 138.383333°E on 26 May 1974.[1]
Description edit
The mineral composition of the Brachina meteorite is olivine (80%), plagioclase (10%), Clinopyroxene (5.5%), iron-sulfide (3%), chromite (0.5%), chlorapatite (0.5%) and pentlandite (0.3%) and traces of meteoric iron. Melt inclusions consist of glass with orthopyroxene and anorthoclase. The chemical and mineralogical composition is similar to the Chassigny meteorite, but the trace elements are fundamentally different.[2]
Parent body edit
Melt inclusions indicate that there were melting processes active on the brachinite parent body.[2]
Classification edit
The meteorite was classified as a chassignite in 1978,[3] but in 1983 trace element analysis showed that the Brachina meteorite was fundamentally different from Chassigny. It was therefore proposed that the meteorite should be the type specimen of a new meteorite class, the brachinites.[2] This classification has remained valid since then.[1][4]
See also edit
References edit
- ^ a b "Brachina". Meteoritical Society. Retrieved 15 December 2012.
- ^ a b c Nehru, C. E.; Prinz, M.; Delaney, J. S.; Dreibus, G.; Palme, H.; Spettel, B.; Wänke, H. (1 January 1983). "Brachina: A new type of meteorite, not a chassignite". Journal of Geophysical Research. 88 (S01): B237. Bibcode:1983JGR....88..237N. doi:10.1029/JB088iS01p0B237.
- ^ Graham, A. L. (1978). "Meteoritical Bulletin, No. 55". The Meteoritical Bulletin. 55: 331. Bibcode:1978Metic..13..327G.
- ^ Grady, Monica M. (2000). Catalogue of meteorites (5th ed. rev. and enl. ed.). Cambridge: Cambridge University Press. ISBN 9780521663038.