Brachina meteorite
| 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″S138°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) |
TheBrachina meteoriteis the type specimen of thebrachinitesclass of theasteroidal achondrites.
Naming and discovery
[edit]The meteorite is named afterBrachinainSouth Australia.Two fragments (total 200 g) were found by B.M. Eves at31°18′00″S138°23′00″E/ 31.300000°S 138.383333°Eon 26 May 1974.[1]
Description
[edit]The mineral composition of the Brachina meteorite isolivine(80%),plagioclase(10%),Clinopyroxene(5.5%), iron-sulfide (3%),chromite(0.5%),chlorapatite(0.5%) andpentlandite(0.3%) and traces ofmeteoric iron.Melt inclusions consist of glass withorthopyroxeneandanorthoclase.The chemical and mineralogical composition is similar to theChassigny meteorite,but the trace elements are fundamentally different.[2]
Parent body
[edit]Melt inclusions indicate that there were melting processes active on thebrachiniteparent body.[2]
Classification
[edit]The meteorite was classified as achassignitein 1978,[3]but in 1983 trace element analysis showed that the Brachina meteorite was fundamentally different fromChassigny.It was therefore proposed that the meteorite should be the type specimen of a new meteorite class, thebrachinites.[2]This classification has remained valid since then.[1][4]
See also
[edit]References
[edit]- ^ab"Brachina".Meteoritical Society.Retrieved15 December2012.
- ^abcNehru, 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.ISBN9780521663038.