[meteorite-list] Greg Hupé's NWA 4883 eucrite

From: bernd.pauli at paulinet.de <bernd.pauli_at_meteoritecentral.com>
Date: 12 Dec 2007 18:52:06 UT
Message-ID: <DIIE.000000B3000023AA_at_paulinet.de>

Greg enthusiastically informed us:

"I would like to announce a new and 'unique' maskelynite-rich poly-
 mict eucrite breccia, NWA 4883. It is a highly shocked eucrite..."

That's a truly 'unique' eucrite that was originally thought to be a howardite
probably because of all those limpid crystals (cp. provisional classification
in the Met.Bull.) and those diverse clasts.

What makes it so unique? One key feature surely is *complete maskelynitization*
due to *intense shock*. Well, let's have a look. Apart from the Antarctic eucrites,
which are unavailable to collectors, there is NWA 2913 but it shows only partial

NWA 3122: this eucrite is highly shocked (S4-5) and thus contains maskelynite!
NWA 1981 is S5 and that's why maskelynite is present.
NWA 1000: about half of the plagioclase shock-altered to maskelynite
NWA 2063: "only" incipient maskelynite (in other words: weakly shocked)
NWA 1980: "minor development of maskelynite"
NWA 2066: "only" incipient maskelynite

As you can see, there are only 3 eucrites (NWA 1981, 3122, 4883) out there that
are so intensely shocked that they contain appreciable amounts of isotropic glass
(maskelynite) and so I am glad I was able to secure my piece of this HED achondrite!

Best pre-Xmas

Received on Wed 12 Dec 2007 01:52:06 PM PST

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