[meteorite-list] Types of twinning in chondrites?

[Bernd V. Pauli]

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