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High‐pressure transformation of pyrope (Mg 3 Al 2 Si 3 O 12 ) in a sintered diamond cubic anvil assembly
Author(s) -
Ito E.,
Kubo A.,
Katsura T.,
Akaogi M.,
Fujita T.
Publication year - 1998
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/98gl00519
Subject(s) - pyrope , stishovite , orthorhombic crystal system , perovskite (structure) , mineralogy , materials science , diamond anvil cell , corundum , diamond , chromite , phase (matter) , geology , crystallography , high pressure , crystal structure , metallurgy , thermodynamics , chemistry , quartz , physics , organic chemistry
Transformation of pyrope garnet was investigated at 1600°C and at pressures higher than 35 GPa using a sintered diamond cubic anvil assembly in a double‐staged split‐sphere apparatus. Pyrope transformed into orthorhombic perovskite at ca. 37 GPa, whereas a small amount of corundum coexisted with perovskite at lower pressures. The unit cell dimensions of perovskite were determined to be a = 4.771(2) Å, b = 4.947(2) Å, c = 6.950(3) Å, and V = 164.0(2) ų. A trace of stishovite observed in the run products may be evidence of nonstoichiometry in the perovskite. These results support the view that perovskite is the major host phase of Al 2 O 3 in the lower mantle.
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