[meteorite-list] Classification question-Equilibration vs Differentation

From: David Weir <dgweir_at_meteoritecentral.com>
Date: Thu Apr 22 10:14:08 2004
Message-ID: <3EAD9FC1.58445E9C_at_earthlink.net>

Hello Lars,

I can add a bit to what has been said, although it may add further
confusion. I know that petrographic type 3 is defined as unequilibrated,
but from what I have read, the subtypes (3.0-3.9) also further divide
this into "unequilibrated" and "highly unequilibrated". The following
paragraph was taken from my website but unfortunately I did not record a
reference.
_______________________________

Just as there exists a metamorphic discontinuity in
the SiC content of the ordinary chondrite groups (between
petrologic grades 3.4 and 3.5), the CO group shows a similar
hiatus between petrologic grades 3.0 and 3.1, defining those
members that are highly unequilibrated.
_______________________________

So it seems that a different division exists for different meteorite
classes. This is something I'll try to research better.

Regards,
David
Received on Mon 28 Apr 2003 05:40:17 PM PDT