Abstract
Chemical and crystallographic properties of clinopyroxene exsolution in wollastonite are described from metamorphosed calc-silicate granulite, Namaqualand, South Africa. The wollastonite is Ca1.96Fe0.01Al0.01 Si2.01O6 belonging to space group P21/a (2M polytype) and the clinopyroxene is Ca0.99 Mg0.75-0.80 Fe0.17-0.21 Na0.02 Al0.03 Si1.99-2.00 O6 belonging to C2/c. An electron backscattered diffraction investigation suggests that the clinopyroxene lamellae elongated along [111] lie on (120) and (100) of the wollastonite-2M, and [11̄0] of both lamellae are parallel to [001] of the wollastonite-2M. The formation of the exsolution probably results from the relatively high peak metamorphic temperature (800-860°C) of the Namaqualand granulite and its slow cooling rate.
| Original language | English |
|---|---|
| Pages (from-to) | 446-450 |
| Number of pages | 5 |
| Journal | American Mineralogist |
| Volume | 91 |
| Issue number | 2-3 |
| DOIs | |
| Publication status | Published - 2006 |
| Externally published | Yes |
Keywords
- Clinopyroxene
- EBSD
- Exsolution
- TEM
- Wollastonite
ASJC Scopus subject areas
- Geophysics
- Geochemistry and Petrology