High‐pressure phase transformation in CaMgSi₂O₆ and implications for origin of ultra‐deep diamond inclusions

Abstract

Additional quench experiments were also carried out using a multianvil apparatus in order to further explore the phase relations and to study chemical compositions of the coexisting phases at various pressures and temperatures.

Melting phase relations in the MgSiO3–CaSiO3 system at 24 GPa

“…However, there are some difficulties in obtaining the degree of melting by high-pressure melting experiments under thermal gradients because the observed degree of melting arises from the thermal gradients, not from the phase equilibrium. Figure 8 shows the eutectic temperatures of the MgO-MgSiO 3 system calculated using interaction parameters constrained from the chemical analyses of the recovered diamond anvil cell (DAC) samples (Ohnishi et al 2017) and those measured directly by , the open diamonds represent the subsolidus phases, the cross symbols represent the subsolidus phases at 25 and 27 GPa reported in Irifune et al (2000), and the dashed gray line represents the subsolidus phases at 25 GPa reported in Jung and Schmidt (2011) pyrometry in DAC experiments (Baron et al 2017). As shown in Fig.…”

“…Indeed, Komabayashi et al (2007) showed that CaSiO 3 perovskite undergoes a phase transition from tetragonal to cubic above5 00 K at~24 GPa. We determined the interaction parameter W solid by fitting our experimental data together with the dataset of Irifune et al (2000) to the following equations:…”

Luminescent properties of CaMgSi2O6-based phosphors co-doped with different rare earth ions

“…CaMgSi 2 O 6 pyroxene (diopside) is a major mineral of peridotites and basalts, and an important constituent of the mantle and subducting slabs, which have been studied by many researchers [1][2][3]. Yet, up to now, the use of CaMgSi 2 O 6 as the luminescent host is rarely reported.…”

Studies on the photoluminescence behavior of rare earth (Ce, Sm Eu, Dy, Tb) activated calcium magnesium silicate phosphors

“…Cameron and Papike (11) described two types of cation positions, designated as M 1 and M 2 . Site M 1 is smaller than M 2 and lies between the apices of opposing tetra-hedra forming an almost regular octahedron [16]. Site M 2 lies between the bases of the tetrahedral forming distorted six or eightfold sites.…”