TY - JOUR
T1 - Crystal chemistry of forsterite
T2 - A first-principles study
AU - Wentzcovitch, Renata M.
AU - Stixrude, Lars
PY - 1997
Y1 - 1997
N2 - We present a first-principles study (local density approximation) of the structural properties of forsterite under pressure. This highly anisotropic magnesium orthosilicate is the most abundant phase of the Earth's upper mantle, and its elastic properties determine the rheology of this region. We perform full structural optimizations and investigate its compressive behavior up to 25 GPa. We obtain a pressure dependence of lattice parameters that agrees well with experiments to 17.2 GPa. We predict that the coordination polyhedra compress essentially isotropically, and we explain the anisotropy of forsterite in terms of the nonuniform distribution of coordination polyhedra having different but nearly uniform compressibilities. In agreement with Brodholt et al. (1996). we do not find theoretical evidence for sudden changes in compression mechanisms in this mineral as had been suggested from experiments. Our results support the hypothesis that such compressive anomalies are caused by solidification of the pressure medium.
AB - We present a first-principles study (local density approximation) of the structural properties of forsterite under pressure. This highly anisotropic magnesium orthosilicate is the most abundant phase of the Earth's upper mantle, and its elastic properties determine the rheology of this region. We perform full structural optimizations and investigate its compressive behavior up to 25 GPa. We obtain a pressure dependence of lattice parameters that agrees well with experiments to 17.2 GPa. We predict that the coordination polyhedra compress essentially isotropically, and we explain the anisotropy of forsterite in terms of the nonuniform distribution of coordination polyhedra having different but nearly uniform compressibilities. In agreement with Brodholt et al. (1996). we do not find theoretical evidence for sudden changes in compression mechanisms in this mineral as had been suggested from experiments. Our results support the hypothesis that such compressive anomalies are caused by solidification of the pressure medium.
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U2 - 10.2138/am-1997-7-802
DO - 10.2138/am-1997-7-802
M3 - Article
AN - SCOPUS:0007187248
SN - 0003-004X
VL - 82
SP - 663
EP - 671
JO - American Mineralogist
JF - American Mineralogist
IS - 7-8
ER -