Brachinite

Slice of the Northwest Africa 3151 meteorite.

Brachinites are a group of meteorites that are classified either as primitive achondrites or as asteroidal achondrites. Like all primitive achondrites, they have similarities with chondrites and achondrites. Brachinites contain 74 to 98% (Volume) olivine.

Naming and history

Brachinites are named after the Brachina meteorite, the type specimen of this group which in turn is named after Brachina, South Australia.^[1]

Description

Brachinites are almost entirely made from olivine (74-98 Volume-%). Other minerals include plagioclase (6.7 to 12.9%), iron sulfides (1.8 - 4.0%), clinopyroxene (1.5 - 8.2%) and orthopyroxene (0 - 2.4%). Trace minerals include phosphates and meteoric iron. The only deviation from chondrites is the very high olivine/orthopyroxene ratio.^[2]

Specimen

There are currently 30 meteorites that are classified as brachinites.^[3] A notable example is the type specimen, the Brachina meteorite.

Origin

Research has indicated that the parent body of brachinites might be the Nenetta Asteroid (289 Nenetta).^[4]

See also

• Glossary of meteoritics

References

1. "Brachina". Meteoritical Society. Retrieved 15 December 2012.
2. Nehru, C. E.; M. Prinz; M. K. Weisberg; M. Ebihara; R. N. Clayton; T. K. Mayeda (1992). "Brachinites: A New Primitive Achondrite Group". Meteoritics. 27 (3): 267.
3. "Meteoritical Bulletin Database". Meteoritical Society. Retrieved 20 December 2012.
4. http://www.newark.osu.edu/facultystaff/personal/jstjohn/Documents/Rocks-from-Outer-Space/Brachinite.htm[]