[meteorite-list] Types of twinning in chondrites?

From: Bernd V. Pauli <bernd.pauli_at_meteoritecentral.com>
Date: Sat, 22 Feb 2014 19:49:05 +0000
Message-ID: <DIIE.00000060000075DD_at_10.0.100.101>

Hello All,

Jim Wooddell inquired:

"what types of crystal twinning do we see the most in OC's?"

Alan Rubin kindly posted:

"The most common type of twinning in chondrules in unmetamorphosed
chondrites is found in low-Ca clinopyroxenes. It is polysynthetic twinning
 -- it looks like the pyroxene grains have narrow stripes. These disappear
when temperatures go above 630 C or so and won't be found in orthopyroxene."

Interesting additional information can be found in our late O.R. Norton's book:

=> NORTON O.R. (2008) Field Guide to Meteors and Meteorites <=

... on these pages: 217 (Figure 11.18), 228 (Figure 11.44), 241 (Minerals in Meteorites)

Bernd
Received on Sat 22 Feb 2014 02:49:05 PM PST