[meteorite-list] NWA 1839 reclassification

From: j.divelbiss_at_att.net <j.divelbiss_at_meteoritecentral.com>
Date: Sat Oct 16 16:08:21 2004
Message-ID: <101620042008.17956.41717FAE00019D9E0000462421602807419C9C070D040A90070BD206_at_att.net>

David, Nelson and others:

NWA 1839 paired with NWA 3133.................wind blowing, tumble weeds rolling, dust in the air, etc. There seems to be a ghost town of a response to this announcement.

As David implied to me in another email...this news has a double edge to it. Nelson's 1839 material is probably paired to the new and exciting NWA 3133 ungrouped achondrite, but in turn it is not the extremely rare L7 that it was first thought to be. One hole is filled and another reopens for us type collectors.

The quest continues for David and others like myself,

John




 

-------------- Original message from David Weir : --------------

> Hello list,
>
> I received this from Nelson to post since his computer is not
> cooperating. He also mentioned that it is possibly paired with NWA 3133.
>
> David
>
> ---------------------------------------------------------------------
>
> Northwest Africa 1839
> Morocco
> Found 2003
> Primitive achondrite (ungrouped)
> A 121.8 g, partially crusted stone was purchased in Rissani, Morocco in
> June 2003. Description and classification (T. Bunch and J. Wittke, NAU):
> polygonal, equigranular (<0.75 mm grain size); no relict chondrules;
> prominent twinning in plagioclase. Mineral modes: orthopyroxene, 37 vol.
> %; olivine, 35 vol. %; plagioclase, 12 vol. %; Ca-rich pyroxene, 6 vol.
> %; troilite, 4.5 vol. %; metal (taenite only), 3.5 vol. %; chromite, 2
> vol. %. Very homogeneous; silicate compositional range is within the
> analytical precision of ± 0.2 mol %. Orthopyroxene, Fs18.9Wo2.3, FeO/MnO
> = 41; olivine, Fa22.0, FeO/MnO = 63; plagioclase, An53.4Or2.2;
> clinopyroxene, Fs7.2Wo47; taenite, Ni = 16.7 wt. %; chromite, Cr/(Cr+Al)
> = 73. Oxygen isotope (D. Rumble, CIW) replicate analyses of acid-washed,
> bulk sample by laser fluorination gave d18O = 0.51 and - 0.73, d??O =
> -3.54 and - 4.57; D17O = - 4.18 and - 3.81 that plot near the CCAM line
> and within the region of CV compositions. Shock level, S1; weathering
> grade is W2. Specimens: 20.1 g, NAU; main mass, Oakes.
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Received on Sat 16 Oct 2004 04:08:15 PM PDT