Structural relaxation around substitutional Cr3+ in pyrope garnet

Structural relaxation around substitutional Cr3+ in MgAl2O4

Solubility of water in pyrope-rich garnet at high pressures and temperature

[1] The water solubility in pyrope-rich garnet was determined between pressures of 5–9 GPa and temperatures of 1373– 1473 K under silica activity and oxygen fugacity similar to those expected in the Earth’s upper mantle. We found that pyrope-rich garnet has substantial water solubility up to 0.1 wt% under these conditions. In addition, the water content in garnet varied as a function of chemica...

Crystal structure and Raman spectrum of a high-pressure Li-rich majoritic garnet, (Li2Mg)Si2(SiO4)3

A Li-rich majoritic garnet (LiMGt), (Li2Mg)Si2(SiO4)3, was synthesized at 15 GPa and 1500 °C and its structure studied with single-crystal X-ray diffraction and Raman spectroscopy. It is cubic with space group Ia3d and unit-cell parameters a = 11.2660(2) Å and V = 1429.91(1) Å3. The 8-, 6-, and 4-coordinated cation sites in LiMGt are occupied by (Li+ + Mg2+), Si4+, and Si4+, respectively. Where...

Mineral inclusions in pyrope crystals from Garnet Ridge, Arizona, USA: implications for processes in the upper mantle

Mineral inclusions in pyrope crystals from Garnet Ridge in the Navajo Volcanic Field on the Colorado Plateau are investigated in this study with emphasis on the oxide minerals. Each pyrope crystal is roughly uniform in composition except for di€usion halos surrounding some inclusions. The pyrope crystals have near constant Ca:Fe:Mg ratios, 0.3 to 5.7 wt% Cr2O3, and 20 to 220 ppm H2O. Thermobaro...

Ce and La single- and double-substitutional defects in yttrium aluminum garnet: first-principles study.

The atomistic structure, energetics, and electronic structure of single-substitutional Ce and La defects and double-substitutional Ce-La defects in Ce,La-codoped yttrium aluminum garnet (YAG) Y(3)Al(5)O(12) have been studied by means of first-principles periodic boundary conditions density functional theory calculations. Single substitution of Y by Ce or by La produces atomistic expansions arou...