[meteorite-list] AL HAGGOUNIA 001 ("NOT" AUBRITE)

From: Adam Hupe <raremeteorites_at_meteoritecentral.com>
Date: Sat, 1 Dec 2007 00:07:24 -0800 (PST)
Message-ID: <39255.60839.qm_at_web30701.mail.mud.yahoo.com>

Jason,

I never called it a type three if you read my emails
although I am confident with the designation
scientists with decades of experience assigned it. I
am certainly no expert on the degree of metamorphism
determing petrologic types in chondrites so I will
present some notes collected from various resources in
regards to this meteorite.

Not only is the object in earlier posted image an
obvious chondrule, it is a very well-formed,
sharp-edged radial pyroxene chondrule (with a clear
annular rim) containing glass (now largely dissolved
out), and this and others like it are the basis for
the Type 3 designation, along with the fact that the
matrix is not at all recrystallized but instead
"primitive". Finally it is not the low abundance of
chondrules that is important, but their form and glass
content and the matrix texture as confirmed by several
chondrite experts.

As far is it being an Aubrite, there is the lack of a
distinctive type of microstructure (polysynthetic
twinning) in the enstatite grains in the Al Haggounia
material, but which to my knowledge is present in all
aubrites (because of their high temperature igneous
history).

Here is a link to the meteorites.tv site that has the
clear definition of an Aubrite:
http://www.meteorites.tv/index.html?lang=en-us&target=d281.html

Finaly, the so-called f-clasts found in some real
Aubrites are from brecciating impactors but this is
not what we're talking about here. The chondrules
found in Al Haggounia 001 are clealy native to the
matrix and not from an impactor so this argument holds
no water.

It is very obvious to me that Al Haggounia 001 is an
EL Chondrite and with all E-Chondrites, there is a
close kinship to Aubrites.

Best Regards,

Adam
Received on Sat 01 Dec 2007 03:07:24 AM PST