Winonaite
Winonaites are primitive achondrites closely related to the silicate inclusions found in IAB iron meteorites.
An archaeological dig supplied the type specimen of the winonaites: Winona, a weathered stone of about 24 kilograms found in 1928 by archaeologists working at a Sinagua site in northern Arizona, where it had apparently been placed in a stone-lined cist. Winonaites are fine- to medium-grained, roughly chondritic rocks of olivine, pyroxene, plagioclase, iron-nickel metal and troilite. Their minerals are fairly reduced, and some members preserve relict chondrules.
Winonaites record partial melting and recrystallisation, with local removal of metal–sulfide and silicate melt. Their importance comes from their oxygen isotopes and mineral compositions, which match the silicate inclusions found in IAB iron meteorites. Most researchers therefore think winonaites and IAB irons came from the same parent body, one that was partly melted and then disrupted and reassembled by a major collision, mixing metallic and silicate material.
Another member is Pontlyfni, a small stone that fell in north Wales on 14 April 1931, and Mount Morris (Wisconsin) is also well known. Recognition relies on texture, reduced mineral compositions, and oxygen isotopes that plot with the IAB silicate inclusions.
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