Premium
Stability of hydrous phases in the transition zone and the upper most part of the lower mantle
Author(s) -
Ohtani Eiji,
Shibata Takeo,
Kubo Tomoaki,
Kato Takumi
Publication year - 1995
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 - 10.1029/95gl02338
Subject(s) - brucite , forsterite , transition zone , geology , phase (matter) , mantle (geology) , mineralogy , slab , phase transition , analytical chemistry (journal) , thermodynamics , materials science , chemistry , geochemistry , geophysics , physics , magnesium , organic chemistry , chromatography , metallurgy
Phase relation for Mg 2 SiO 4 +20.4 wt.%H 2 O composition was studied in the pressure range from 11 GPa to 22.5 GPa. The sequence of the phase transitions in the temperature range from 800°C to 1000°C with increasing pressure was as follows; Forsterite + Water → Phase A + Clinoenstatite + Water → Phase E + Water → Superhydrous phase B + Phase F + Water → Brucite + Phase F (+Water). Coexistence of brucite and phase F was observed at pressures above 20 GPa. These phases are stable at least up to 22.5 GPa and around 1000°C, and are the candidates for the hydrous phase in a cold slab descending into the base of the transition zone and the uppermost part of the lower mantle.