[meteorite-list] Bencubbinites

From: Bernd Pauli HD <bernd.pauli_at_meteoritecentral.com>
Date: Thu Apr 22 09:48:13 2004
Message-ID: <3BD1708D.E8E49F4B_at_lehrer1.rz.uni-karlsruhe.de>

Steve Witt wrote:

> thanks to ... Bernd and Eric Twelker for
> their answers to my chondrite inquiry.

Eric wrote:

> Don't forget Gujba - the only fall and arguably the most spectacular of
> the Bencubbinites (Meteoritical Bulletin No. 85, 2001). I have posted
> a larger scale scan at

http://www.meteoritemarket.com/GUJpicture.htm

Bernd: No, I shouldn't have forgotten that aesthetic beauty!!!
Interestingly, it was considered a mesosiderite back in the 80s.

It is so "fresh" that it has even got a "W0" classification.

Reference:

ISLAM M.R., OSTAFICZUK, S. (1988) The Gujba mesosiderite: its
petrology, mineralogy and impact (Annals of Borno 5, 110-124).


Hello Steve, Eric, and List,

For objectivity's sake, let me add that the views of WEISBERG M.K. et
al. are not undisputed. In their recent paper on HaH 237 and QUE 94411,
Krot A.N. et al. mention the following:

"Wasson and Kallemeyn (1990) and Wasson (2000, pers, comm.) questioned
the classification of the QUE 94411/94627, HH 237 and CH chondrites as
primitive carbonaceous chondrites and suggested that their unusual
mineralogical and chemical characteristics could have resulted from
melting, vaporization, outgassing, condensation, and size-sorting in a
cloud of impact ejecta on the CR parent asteroid. In this model, CAIs
are conceived as foreign objects that were randomly mixed in the ejecta
during late stages of the impact process."

Krot et al. argue that: "the characteristics of the CAIs and
Al-diopside-rich chondrules in QUE 94411/94627 and HH 237 are
inconsistent with an impact origin for these metal-rich chondrites."

KROT A.N. et al. (2001) Refractory Ca, Al-rich inclusions and
Al-diopside-rich chondrules in the metal-rich chondrites HaH 237
and QUE 94411 (MAPS 36-9, 2001 pp. 1189-1216).


Best wishes,

Bernd
Received on Sat 20 Oct 2001 08:39:41 AM PDT