[meteorite-list] NWA 540

From: bernd.pauli_at_paulinet.de <bernd.pauli_at_meteoritecentral.com>
Date: Tue Oct 19 13:54:19 2004
Message-ID: <DIIE.0000002100002ADA_at_paulinet.de>

Martin wrote:

> I posted a couple pics of a wildly melted NWA slice. This is
> the famous NWA 540 which was first offered for sale a few
> years ago, but then pulled completely from the market and
> 'sold' to a Canadian museum for a very high price where it
> will likely be preserved forever.

> http://challenge.isu.edu/nwa540bw.jpg

> http://challenge.isu.edu/nwa540aw.jpg

> Should anyone want to purchase this amazing 132g slice
> let me know. All serious offers will be entertained.

Here is what Martin wrote when he first mentioned this meteorite
on the Meteorite Central List:

A friend of mine who is a planetary geologist took a look at an image
of my slice of NWA 540, the one pictured above. Here are his comments:
The images look fine. I'm not sure if the roundish inclusions are true
chondrules or something else, perhaps CAI's? There certainly is a fair
amount of metal. The veins contain an amorphous looking substance that
could very well be partial melt related to an impact. They probably represent
the injection of liquid from adjacent regions, not partial melting of the rock
we see here. The rinds along the edges of these zones are fairly thin and have
sharp contacts with the host rock, meaning that the melt was chilled against
the host with minimal reaction. The host rock seems to be unaffected at the
macroscopic scale, i.e., there are not small fingers and pockets of partial melt
between more refractory inclusions. In other words, the rock was not heated
slowly to its melting point, which would cause it to melt uniformly rather than
in veins. If this was an example of in-situ magmatic melting, you would probably
see coalescent blobs of melt and tiny fractures fingering away from veins or
other zones of accumulation.


Best regards,

Bernd
Received on Tue 19 Oct 2004 01:53:09 PM PDT