[meteorite-list] Udei Station vs. NWA 4024 winonaite types

From: Jeff Kuyken <info_at_meteoritecentral.com>
Date: Sun, 27 Feb 2011 15:02:58 +1100
Message-ID: <9099D9EED274419D8954AFBCBACDB585_at_JeffPC>

G'day Mike,

I asked this very same question about a year ago and got some very good
replies. Here are some of them:

http://six.pairlist.net/pipermail/meteorite-list/2010-March/062685.html
http://six.pairlist.net/pipermail/meteorite-list/2010-March/062688.html
http://six.pairlist.net/pipermail/meteorite-list/2010-March/062729.html
http://six.pairlist.net/pipermail/meteorite-list/2010-March/062736.html

Bernd summarised with the following:

"It is likely that the winonaites cooled faster than the silicates in IAB
irons,
which may have been more deeply buried. This is supported by the metallo-
graphic cooling rates of Winona, 200?C/Myr, and IAB irons, 10-50?C/Myr.

So, maybe these metallographic cooling rates can help make a clear(er)
distinction between the two: Silicated IAB's and winonaites."

Cheers,
Jeff Kuyken
Meteorites Australia
www.meteorites.com.au
Vice President - I.M.C.A. Inc.
www.imca.cc


----- Original Message -----
From: "tett" <tett at rogers.com>
To: <meteorite-list at meteoritecentral.com>
Sent: Saturday, February 26, 2011 10:39 PM
Subject: [meteorite-list] Udei Station vs. NWA4024 winonaite types


> List,
>
> When stumbling across an ad for NWA4024 I saw pictures of the meteorite
> and immediately thought how similar it looks to Udei Station. Comparing
> the pics of NWA4024 and my slices of Udei Station reveal very similar
> compositions. However, NWA4024 is classiifed as a winonite where as Udei
> Station is classified as an IAB iron.
>
> Further research shows that it is likely Udei Station and other IAB irons
> along with Winonites come from the same parent body. My question is,
> what is the dividing line between Winonites and IAB's? How does one
> decide which group the meteorite should fall? Is it %Fe?
>
> Thanks for any help and
>
> Cheers!
>
> Mike Tettenborn
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Received on Sat 26 Feb 2011 11:02:58 PM PST