AW: [meteorite-list] Seymchan Pallasite

From: Jörn Koblitz <koblitz_at_meteoritecentral.com>
Date: Mon Sep 20 08:11:39 2004
Message-ID: <E5E6112EA31FA24CB448E091C6883C050EBCDA_at_server2000.microfab.de>

Hello Mark and List,

here is an extract from MetBase on Seymchan:

-------------------------------------------------------
A mass of 272.3kg was found in the bed of a stream flowing into the river Hekandue, a tributary of the Jasachnaja, a second mass of 51kg was later found at a distance of 20 m from the first one, Met. Bull. 42, 43, Meteoritics, 1970, 5, p.97; see also, A.L.Graham et al., Cat. Met., 1985, p.323. The coordinates are of the town of Seymchan. Find circumstances, V.I.Tsvetkov, Meteoritika, 1969, 29, p.152. Illustrated description, with an analysis, 9.47% Ni, O.A.Kirova and M.I.Dyakonova, Meteoritika, 1972, 31, p.104. Further analysis, 9.15% Ni, 24.6 ppm Ga, 68.3 ppm Ge, 0.55 ppm Ir, E.R.D.Scott and J.T.Wasson, GCA, 1976, 40, p.103. Further INAA data, previously classified into the IIE group, but now designated ungrouped based on the chemical composition, J.T.Wasson and J.Wang, GCA, 1986, 50, p.725. Another analysis, A.N.Krot et al., Meteoritics, 1992, 27, p.465. Nitrogen isotopic composition, R.L.Palma et al., LPSC, 1997, 28, p.1057 (abs.); see also, K.Marti et al., MAPS, 1997, 32, p.A84 (abs.); K.J.Mathew et al.,
 GCA, 2000, 64, p.545.
-------------------------------------------------------

Acording to the more recent analysis by Wasson and Chang (1986), the metal of Seymchan is ungrouped, thus cannot be related to - at least - the main-group pallasites (e.g. Brenham, Esquel, Imilac) which are genetically linked to IIIAB irons.

So, may be we have a new kind of pallasite here (exotic like e.g. Eagle Station)!

On the other hand, rounded silicate inclusions are commonly found in IIE irons like Miles, Elga, or Kodaikanal. Thus, it is well possible to mix such silicated irons up with pallasites and Seymchan is actually an ungrouped silicated iron.

Best regards,
J?rn

_______________________________________________________________________________
Joern Koblitz
MetBase Editor
The MetBase Library of Meteoritics and Planetary Sciences
Benquestrasse 27
D-28209 Bremen, Germany
phone: +49 421 24 100 24
fax: +49 421 168 2799
email: info_at_metbase.de
_______________________________________________________________________________

 


> -----Urspr?ngliche Nachricht-----
> Von: mark ford [mailto:markf_at_ssl.gb.com]
> Gesendet: Montag, 20. September 2004 10:54
> An: Meteorite List
> Betreff: RE: [meteorite-list] Seymchan Pallasite
>
>
>
> Hi,
>
> Anyone got a link to any classification details for this seymchan
> pallasite?
>
> Looks quite interesting, very sharp Olivine pieces....
>
> Best
> Mark
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>
Received on Mon 20 Sep 2004 08:11:35 AM PDT