[meteorite-list] Chico question

From: Bernd Pauli HD <bernd.pauli_at_meteoritecentral.com>
Date: Thu Apr 22 09:43:35 2004
Message-ID: <3B613DB1.15434053_at_lehrer1.rz.uni-karlsruhe.de>

Steve Witt inquired:

> I recently acquired a small specimen of Chico (L6 Impact Melt
> Breccia). On one side of the specimen between the two lithologies
> present, is an area that is about 1mm wide X 4mm long that is a
> completely transparent material.


Hi Steve and List,

As Chico is an impact melt breccia (by the way, it also contains copper)
that has been severely shocked (shock stage 6 = very strongly shocked
with recrystallization of olivine and phase transformations of olivine
[=>ringwoodite] through a series of impacts as the asteroid parent body
collided with other objects, I'd settle on maskelynite (plagioclase
feldspar transformed by intense shock pressure).

For more details on such processes, see also:

KEMPTON R. (1997) Centerpiece - Cat Mountain
(M!, May 97, Vol. 3, No. 2).


Best wishes from 95°+
Southern Germany,

Bernd
Received on Fri 27 Jul 2001 06:08:49 AM PDT