Single-crystal compression and crystal structure of clinopyroxene up to 10 GPa

Characterization of synthetic hedenbergite (CaFeSi 2 O 6 )?petedunnite (CaZnSi 2 O 6 ) solid solution series by X-ray powder diffraction and 57 Fe M�ssbauer spectroscopy

“…A yield of euhedral hedenbergite crystals up to 70 lm in length and 50 lm in width was observed at higher pressures (1.2 Gpa, 900°C, 22 h, Table 1, Hd10h). Similar-sized hedenbergite crystals were reported by Zhang et al (1997) from synthesis experiments at 4 GPa and 1150°C. High-pressure synthesis of hedenbergite was also carried out by Perkins and Vielzeuf (1992), who grew 10-30 lm hedenbergite grains of from high-purity reagents (Fe metal, Fe 2 O 3 , CaCO 3 and Brazilian quartz) using two cycles.…”

“…The structures of end members hedenbergite and petedunnite were refined by Clark et al (1969) and Ohashi et al (1996), respectively. Hydrothermal synthesis of hedenbergite was performed by Nolan (1969), Rutstein and Yund (1969), Turnock et al (1973), Gustafson (1974), Kinrade et al (1975), Burton et al (1982), Haselton et al (1987), Moecher and Chou (1990), Raudsepp et al (1990), Perkins and Vielzeuf (1992), Kawasaki and Ito (1994), Zhang et al (1997) and Redhammer et al (2000). The stability of hedenbergite at 0.2 GPa as a function of temperature and oxygen fugacity was determined by Gustafson (1974) and Burton et al (1982).…”

The effect of pressure on the elastic properties and seismic anisotropy of diopside and jadeite from atomic scale simulation

“…This data permits the recovery of the average bulk and shear moduli along with their temperature and pressure derivatives. The measured temperature derivatives are within error of the averaged values of Isaak et al (2006) and the bulk modulus and its pressure derivative is broadly compatible with scattered results from compression experiments (Levien and Prewitt, 1981;Zhang et al, 1997;Zhao et al, 1998;Tribaudino et al, 2000;Thompson and Downs, 2008). Although these data can be used to interpret the seismic wave velocities in much of the upper mantle, averaged elastic moduli are not sufficient for the analysis of seismic anisotropy: the pressure derivatives of the individual elements of C ij are required.…”

“…Table 2 Elastic constants (in GPa) of jadeite compared with experimental data from Brillouin spectroscopy of Kandelin and Weidner Kandelin and Weidner (1988). Kandelin and Weidner (1988) (Nestola et al, 2006;Zhao et al, 1997;Knight and Price, 2008, respectively), circles, upward pointing triangles, downward pointing triangles and crosses: diopside (Tribaudino et al, 2000;Levien and Prewitt, 1981;Zhang et al, 1997;McCormick et al, 1989, respectively). …”

A Single-Crystal Neutron-Diffraction Investigation of Diopside at 10 K

“…The reference clinopyroxene end-member is diopside (CaMgSi 2 O 6 ); in fact, the composition of natural clinopyroxenes, for example augite, can be derived by solid solution in the cation sites of diopside. Therefore, several structural investigations have been performed on both natural and synthetic diopside to clarify its structural features in relation to those of other clinopyroxenes at room (Clark et al 1969, Bruno et al 1982 and nonambient conditions (high pressure: Levien & Prewitt 1981, Zhang et al 1997high temperature: Cameron et al 1973, Finger & Ohashi 1976. The main result of the cited papers was a description of the evolution of the average bond-lengths and distortion of polyhedra as a function of temperature (T), pressure (P) and composition.…”