[meteorite-list] AD- Coins, Space Envelope and Stable Morasko !

From: David Weir <dgweir_at_meteoritecentral.com>
Date: Mon, 04 Dec 2006 16:24:55 -0500
Message-ID: <45749227.7020800_at_earthlink.net>

Hello,

According to Buchwald, the production of fusion crust does occur in
irons, while heat-affected rim zones are present below this fusion
crust. Partially quoting from his first volume, in the chapter Shapes
and Surface Characteristics, he writes that these fusion crusts differ
from those of stones in that iron fusion crusts consist of complex,
mixed melts of fully and partially oxidized metal. The oxide melts have
solidified and decomposed to wustite-magnetite layers, while the
metallic melts have solidified to a multilayer dendritic-cellular zone
transformed to fine-grained martensite. These fusion crusts are only
sub-mm in depth, with another 10 mm of heat-affected zone, where the
temperature didn't rise above 300-400*C. A nice diagram is shown on page
52. I love the photos that are made of the fusion crusts after being
coated with ammonium chloride.

David
Received on Mon 04 Dec 2006 04:24:55 PM PST