[meteorite-list] debat , , monzogabbro /dolerite/ mare basalt/ lunar.

From: habibi abdelaziz <azizhabibi_at_meteoritecentral.com>
Date: Tue, 22 Jan 2008 04:55:53 -0800 (PST)
Message-ID: <352893.43446.qm_at_web62010.mail.re1.yahoo.com>

hello list members ,
 
well , i get just yet an email , about nwa 4734 classification obtain =lunar.
not definitive il ya a parler.
 
1= witch other stone stone is called only lunar,without suite;?
2= first this stone was called monzogabbro than , American scientist call it mare basalt,
3= than there was a proposition for dolerite
4= the nomcom didn't retain any of this for the fact that there is not compromise they say it's a lunar and stop the issue is not finish,
5= American scientist are talking about launch-pairing from ejecta, in other terms a paring from the moon from the crater, with lap 02205-02224-02226-02234-02436-03632
 
6= http://meteorites.wustl.edu/lunar/stones/nwa4734.htm
        http://meteorites.wustl.edu/lunar/chemclass/chemclass_lap02205.htm
        http://www.flickr.com/photos/azizhabibi/sets/72157602531819147/
7=i m happy with my half kilos lunar what ever the name is ,
 
and here is a comment from dr jambon
 
NWA 4734 : Lunar
The appropriate classification for this rock is the subject of discussion between scientists. Its chemical composition is identical to LAP 02205-02224-02226-02234-02436-03632 which have been classified as Mare basalt. The name basalt however is not appropriate as it is a coarse grained rock and the texture is isotropic unlike rapidly cooled rocks from lava flows (basalts).
In the case of terrestrial rocks the name gabbro is usually completed by its subtype. The criteria used for classification are the modal composition and proportion of plagioclase/alkali feldspar and the amount of quartz. NWA 4734 does not contain quartz but abundant silica instead (critobalite partly transformed by shock). This is due to the low pressure (low gravity) at the surface of the Moon. A similar terrestrial rock should be called quartz monzogabbro. For these reasons the Nom Com did not retain Mare basalt, but more simply Lunar, until the classification issue is settled.
The nomenclature for Lunar rocks has been defined in the early seventies when studying the Apollo specimens. The nomenclature for terrestrial magmatic rocks has been published in 1976. Whether this classification can be used for Lunar rocks is the subject of debate; still similar names (e.g. basalts, gabbros etc) are used for both types of rocks.
We must notice that among Lunar rocks most are breccias (e.g. Mare basalt Breccias); other basalts have typical quench textures (e.g. NWA 032/479). NWA 4734 is unique among Lunar meteorites (outside Antarctica) having a coarse grained magmatic texture (not brecciated). LAP samples share with NWA 4734 a similar texture and a similar chemistry (Jambon et al. 2008) and poses the question of possible pairing for rocks found about 25 000 km apart.
Albert JAMBON
Laboratoire Magie
Universit? Pierre et Marie Curie
4 place jussieu 75252 Paris Cedex O5 Franc
 
Streckeisen A. (1976) To each plutonic Rock its proper name. Earth Sci. Rev. 12, 1-33
 
___________________________________________________________________________________
 
my best
aziz habibi

habibi aziz
box 70 erfoud 52200 morroco
phone. 21235576145
fax.21235576170</font>


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Received on Tue 22 Jan 2008 07:55:53 AM PST