[meteorite-list] Coolidge Classification

From: David Weir <dgweir_at_meteoritecentral.com>
Date: Thu Apr 22 09:48:14 2004
Message-ID: <3BE065DC.810FB58_at_earthlink.net>

Hello Bernd and List,

Here is what I have on Coolidge from all that I have found to date:

A very weathered mass of 4.5 kg was found by Harvey Nininger in Hamilton
County, Kansas. Coolidge was originally classified as a metamorphosed
member of the reduced subtype of the CV group. Recent petrographic
studies of Coolidge and two other specimens, Loongana 001 and HaH 073,
defined a petrologic type of 3.8-4, implying that these meteorites are
not simply metamorphosed samples of CV3 material. Another recently found
meteorite, NWA 779, has low fayalite olivine and similar refractory
element abundances which possibly places it within the Coolidge
grouplet.

Only the karoondaites (CK) have petrologic type 4 members in common with
the three (possibly four) Coolidge-type meteorites, but current
oxidation state and bulk composition studies solidly place these
meteorites in their own distinct carbonaceous chondrite grouplet. This
grouplet is also separated by its highly fractionated moderately
volatile elements, higher than all other meteorite groups. The finding
of Al-rich inclusions unique from other carbonaceous chondrites also
support this classification. Coolidge has a CRE age of 37.7 m.y.

Best regards,
David
Received on Wed 31 Oct 2001 03:58:04 PM PST