AW: [meteorite-list] Seymchan question

From: Jörn Koblitz <koblitz_at_meteoritecentral.com>
Date: Mon Nov 8 06:28:03 2004
Message-ID: <E5E6112EA31FA24CB448E091C6883C050EBD33_at_server2000.microfab.de>

Matteo,

Seymchan was first classified as IIE based on metal composition. This classification was revised to "ungrouped" lateron after another analysis was done (see: J.T.Wasson and J.Wang, GCA, 1986, 50, p.725). I assume, all analyses were done of material derived from the 273 kg main mass in Moscow. This piece obviously doesn't show any olivine (at least at the outer visible part). Thus, a classification as a pallasite could not be made as it requires the presence of olivine in shapes and sizes typical for pallasites. If the material which is presently sold as Seymchan is indeed paired with the main mass at Vernadsky Moscow (which is evident), then it must be reclassified from "UNGROUPED IRON" to "pallasite". As it seems that the metal is chemically anomalous with respect to typical main group pallasites, which show composition similar to IIIAB group irons, Seymchan must be regarded an ungrouped pallasite (like e.g. Glorieta Mountain). We will have to wait for new analyses, especially of the silicates, to get a cle
arer picture of its relationship to other known pallasites. The distribution of olivine in Seymchan much resembles those we know from Glorieta Mountain, another ungrouped pallasite. Some larger pieces of Glorieta lacking any olivine.

Best regards,
J?rn Koblitz / MetBase


> -----Urspr?ngliche Nachricht-----
> Von: McomeMeteorite Meteorite [mailto:meteorites_at_hotmail.com]
> Gesendet: Montag, 8. November 2004 11:39
> An: meteorite-list_at_meteoritecentral.com
> Betreff: [meteorite-list] Seymchan question
>
>
>
> Hello
>
> One question on Seymchan, its confirm is a pallasite or is a
> IIE Iron????
> The 2 pieces I have its full of olivine - not to paired to
> silicated - and
> another piece I have in arrive its without olivine, only
> iron. Now, its
> similar to Brenham where the meteorite have and not have
> olivine or is
> another type of meteorite?
>
> Matteo
>
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Received on Mon 08 Nov 2004 06:30:09 AM PST