Winonaite
| Winonaites | |
|---|---|
| — Group — | |
| Type | Primitive achondrite |
| Subgroups |
|
| Parent body | Winonaite-IAB-IIICD[1] |
| Total known specimens | 25 |
Winonaites are a group of
achondrites.[1][2] They show signs of metamorphism, partial melting, brecciation and relic chondrules. Their chemical and mineralogical composition lies between H and E chondrites.[1]
Naming and history
The winonaite group is named after the type specimen, the Winona meteorite. The name itself derived from Winona, Arizona where the type specimen was said to be found during an archaeological excavation of the Sinagua village Elden Pueblo in September 1928. The Sinagua lived in the village between 1150 and 1275. The meteorite was said to be retrieved from the cist of one of the rooms.[3][4] However, a later study indicates the meteorite was found at another Sinagua site and not in Elden Pueblo.[5]
As of 2021, 54 meteorites are included in the winonaite group.[6]
Description
Winonaites are
IAB meteorites. In thin section, the mineral grains show microstructures of extensive thermal metamorphism and signs of partial melting.[7] Some winonaite specimen appear to have relics of chondrules (e.g. Pontlyfni and Mount Morris).[8]
Parent body
Winonaites and the two iron meteorite groups
breccias of different lithologies. Later these breccias were heated and Ar–Ar radiometric ages have constrained the metamorphism on the parent body to between 4.40 and 4.54 billion years. The parent body also reached temperatures where partial melting took place. Cosmic ray exposure ages show that the meteorites took about 20 to 80 million years to reach earth.[8]
Notable winonaite meteorites
- Hammadah al Hamra 193: Amphibole bearing.[9]
- Pontlyfni: Chondrule relics.[7]
- Mount Morris: Chondrule relics.[7]
- Winona meteorite
See also
References
- ^ ISBN 978-0816525621. Retrieved 14 October 2013.
- ^ "PAC Group – Primitive Achondrites". Meteorite.fr. Retrieved 10 December 2012.
- ^ "Winona". meteorites.com.au. Retrieved 5 December 2012.
- ^ M. M. Grady Catalogue of Meteorites (5th ed.) Cambridge UP, 2000, p. 528.
- ^ A. L. Christenson "J. W. Simmons' account of the discovery of the Winona meteorite."Meteorite 10(3):14–16, 2004.
- ^ "Meteoritical Bulletin Database". Meteoritical Society. Retrieved 18 April 2021.
- ^ .
- ^ .
- . Retrieved 6 December 2012.