[meteorite-list] Millbillillie vs Allende ages

From: Dave Harris <entropydave_at_meteoritecentral.com>
Date: Thu Apr 22 10:25:41 2004
Message-ID: <3EC93943.000001.03384_at_bigbertha>

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 Hi Bernd and all,=0D
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Wow - I didn't realise that there was such a mix of lithologies in
Millbillillie - seems that this material was formed over about 1 billion
years if the dates of the lithologies range from the primary xstallisatio=
n
age of ~4.5Gy and these 'microcracks' at about 3.5Gy. I've not come acro=
ss
these microcracks before.=0D
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I'd love to see some pics of these various lithos - anyone got any pics?=0D
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very best=0D
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dave=0D
IMCA #0092=0D
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-------Original Message-------=0D
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From: bernd.pauli_at_paulinet.de=0D
Date: Monday, May 19, 2003 16:21:41=0D
To: entropydave_at_ntlworld.com=0D
Subject: Re: [meteorite-list] Millbillillie vs Allende ages=0D
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> Hullo, =0D
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Hello Dave and List,=0D
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> Millbillillie is from a differentiated body I just wondered if it was t=
hat=0D
> much younger (say 4.4Gy) as there had to be an elapsed time for the=0D
> formation of the eucritic parent body (Vesta, as presently received)?=0D
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Here is some information from an article by Yamaguchi:=0D
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YAMAGUCHI A. et al. (1994) Textural variations and impact=0D
history of the Millbillillie eucrite (Meteoritics 29, 237-245):=0D
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In table 4, page 244, Yamaguchi et al. present a chronological scenario=0D
concerning the formation of five classified lithologies of the Millbillil=
lie=0D
eucrite.=0D
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Stage #1: primary crystallization age of eucrites in general ~4.46-4.56 G=
a=0D
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Stage #2: Impact (brecciation, melting, mixing, deposition)=0D
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Stage #3: Thermal annealing - Granoblastic matrix (3.55 Ga ?)=0D
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Stage #4: Impact - Glassy veins (3.55 Ga ?)=0D
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Stage #5: Impact - Microcracks=0D
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Best regards,=0D
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Bernd=0D
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To: entropydave_at_ntlworld.com=0D
Cc: Meteorite-list_at_meteoritecentral.com=0D
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Received on Mon 19 May 2003 04:06:27 PM PDT