[meteorite-list] Black Inclusions in Howardites

From: Bernd Pauli HD <bernd.pauli_at_meteoritecentral.com>
Date: Thu Apr 22 09:54:10 2004
Message-ID: <3C7A90EB.9C6E4C2E_at_lehrer1.rz.uni-karlsruhe.de>

vincent jacques wrote:

> I look for information and reports of analyses about
> the nature of black inclusions in howardite type.


Hello Vincent and List,

Several howardites (Bununu, Chaves, DaG 779, Hughes 005, Lohawat,
Malvern, Monticello, NWA 776, Old Homestead 001) are glass-rich.
They contain dark, glassy inclusions - not too surprising for
breccias because of their impact history.

Chaves contains both dark brown and also devitrified glasses, which
are intimately associated with crystalline grains of plagioclase and
pyroxene. Monticello is particularly glass-rich (15% dark brown glass
fragments).

The Varela article in MAPS provides very important background info,
figures, photos, and detailed analyses.

References:

VARELA M.E. et al. (1998) The ubiquitous presence of silica-rich glass
inclusions in mafic minerals: Examples from Earth, Mars, Moon and the
aubrite parent body (MAPS 33-5, 1998, 1041-1051).

MONTEIRO J.F. (1989) Preliminary study of the Chaves howardite
(Meteoritics 24-4, 1989, pp. 305-306).

SINGH U.K. et al. (1998) Lohawat howardite: Chemical and mineralogical
characteristics and cosmogenic records (Meteoritics 33-4, 1998, A146).

Olsen E.J. et al. (1986) Monticello: A glass-rich howardite (Meteoritics
22-1, 1987, 81-96).


Best wishes,

Bernd
Received on Mon 25 Feb 2002 02:30:51 PM PST