[meteorite-list] Feldspar minerals in the inclusions in earthly/lunar basalts

From: Robert Verish <bolidechaser_at_meteoritecentral.com>
Date: Thu Apr 22 10:06:14 2004
Message-ID: <20021109011733.76568.qmail_at_web80302.mail.yahoo.com>

--------------- Original Message ---------------
[meteorite-list] Feldspar minerals in the inclusions
in earthly/lunar basalts
Bjørn Sørheim bsoerhei_at_online.no
Fri, 8 Nov 2002 17:22:40 +0100 (MET)

Hello list,

++++SNIP!!++++

But the question I have is concerning the feldspar
inclusions.
I wonder what span in %-values there is of Albite(Na)
vs. Anorthite(Ca) in the plagioclase of these
inclusions in the lunar basalts compared to earthly
basalts?
On the practical side (testing) - would a lunar
basaltic feldspar inclusion fizzle in (cold)
hydrocloric acid (HCl)?
Would a (Vesta) eucrite inclusion have the same values
as its lunar counterpart?

Regards,
Bjørn Sørheim
-----------------------------

Good Questions Bjørn,

Regarding your basalt's Ca-rich plagioclase
phenocrysts

--
I just had a specimen turned-down for formal analysis,
because it failed the very same acid test that you
described.  My immediate question was, How do we know
those aren't lunar anorthosite grains that have
undergone a great deal of terrestrial weathering, and
that have been altered to clays and calcium carbonate?
I'm still waiting for an answer to that question.
So, if there is a geochemist out there on the List
that knows why an acid test fizzle is [always] a
diagnostic contra-indication for a plag-bearing
meteorite, would they please explain to me "why?".  
Bob V. 
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Received on Fri 08 Nov 2002 08:17:33 PM PST