AW: [meteorite-list] NWA 3133

From: Bernhard Rems <rendelius_at_meteoritecentral.com>
Date: Mon Nov 15 16:24:39 2004
Message-ID: <000201c4cb59$7c6ad300$bc4a2fd5_at_rendhome>

Well, the other mail today here wasn't formal, but rather conclusive, I
think. For me, we cannot conclude, but suspect a pairing, or at least a
second NWA with very similar characteristics, right?

Bernhard

-----Urspr?ngliche Nachricht-----
Von: meteorite-list-bounces_at_meteoritecentral.com
[mailto:meteorite-list-bounces_at_meteoritecentral.com] Im Auftrag von Adam
Hupe
Gesendet: Montag, 15. November 2004 22:04
An: meteorite-list_at_meteoritecentral.com
Betreff: [meteorite-list] NWA 3133

Dear List,

Several have been asking about NWA 3133. NWA 3133 is destined to be a
famous set of stones exclusive to the Hupe Collection. NWA 3133 was the
very first achondrite to plot on the CV mixing line using oxygen isotope
testing. It has been stated that NWA 3133 may be the most important
meteorite to have been found in 30 years and is destined to become a
classic
among scientists. There are several abstracts in progress in regards to
NWA
3133 and one that is already complete. Here is a link to the completed
abstract:

http://www.agu.org/meetings/fm04/fm04-sessions/fm04_P31C.html

I have not seen anything formal on any other meteorite that would cause
me
conclude a pairing. Here is the classification submitted to the NomCom:

Northwest Africa 3133
 Morocco
 Purchased 2004 March/August
 Primitive achondrite (anomalous)
Several complete, dense, brown stones (total 2393 g) were purchased in
Tagounite by a Moroccan dealer for A. and G. Hup? (Hup?) in 2004 March
and
August. Classification and mineralogy (T. Bunch and J. Wittke, NAU; A.
Irving and S. Kuehner, UWS): equigranular texture of subhedral to
anhedral
grains with ~120? triple junctions; mean grain size = 0.28 mm. Moderate
but
pervasive weathering (W2) has converted some metal and troilite to brown
iron hydroxides, which also coat grain boundaries. Mineral mode in
vol.%:
olivine 46, orthopyroxene 28, plagioclase 7, Cr-diopside 5,
Na-Mg-bearing
merrillite 4, metal (including associated hydroxides) 5, chromite 3 and
troilite 2. Highly equilibrated mineral compositions: olivine (Fa22.2
to
Fa22.6, FeO/MnO = 57 - 69), orthopyroxene (Fs18.6Wo2.8 to Fs19.2Wo2.1,
FeO/MnO = 38 - 49), diopside (Fs7.3Wo44.6 to Fs8.7Wo42.2, FeO/MnO = 21 -
33,
Cr2O3 = 0.56 to 0.82 wt.%, Al2O3 =1.21 to 1.74 wt.%), plagioclase
(An50.1Or2.5 to An53.5Or2.3), metal (Ni = 17.4 - 20.2 wt.%), chromite
(TiO2
= 2.61 wt.%, Cr/(Cr+Al) = 0.73), troilite (Ni = 1.2 - 5.2 wt.%). Oxygen
isotopes: replicate analyses of an acid-washed whole rock sample by
laser
fluorination (D. Rumble, CIW) gave respectively ?18O = 3.06, 2.46, ?17O
= -1.75, -2.25, ?17O = -3.36, -3.54 per mil, and triplicate analyses of
an
acid-washed olivine-rich separate by laser fluorination (T. Larson and
F.
Longstaffe, UWO) gave respectively ?18O = 1.78, 0.92, 0.89, ?17O
= -2.91, -3.67, -3.62, ?17O = -3.84, -4.16, -4.08 per mil. All of these
oxygen isotope compositions plot on the CV3 mixing line, suggesting that
this achondritic meteorite has affinities with CV chondrites (Irving et
al.,
2004). Specimens: type specimens, 20.1 g, and one polished thin
section,
NAU; 40.3 g, and four polished thin sections, UWS; main mass, Hup?.

Irving, A. J., Larson, T. E., Longstaffe, F. J., Rumble, D., Bunch, T.
E.,
Wittke, J. H. and Kuehner, S. M. (2004) A primitive achondrite with
oxygen
isotopic affinities to CV chondrites: Implications for differentiation
and
size of the CV parent body. Eos, Trans. Amer. Geophys. Union, 85(47),
Fall
Meet. Suppl., Abstract P31C-02.

I hope this clears things up,

Adam




______________________________________________
Meteorite-list mailing list
Meteorite-list_at_meteoritecentral.com
http://six.pairlist.net/mailman/listinfo/meteorite-list
Received on Mon 15 Nov 2004 04:24:25 PM PST