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Role of Water in Deformed Omphacite in UHP Eclogite from the Dabie Mountains, Eastern China
Author(s) -
Wen SU,
Zhendong YOU,
Bolin CONG,
Kai YE
Publication year - 2003
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/j.1755-6724.2003.tb00748.x
Subject(s) - omphacite , eclogite , metamorphic rock , dislocation , geology , dislocation creep , deformation mechanism , transmission electron microscopy , deformation (meteorology) , crystallography , microstructure , materials science , geochemistry , seismology , chemistry , tectonics , subduction , oceanography , nanotechnology
Omphacite grains ftom UHP eclogite of the Dabie Mountains in eastern China are elongated and show strong lattice preferred orientations (LPOs). Observations by the transmission electron microscopy (TEM) identified not only structures of plastic deformation occurring as free dislocation, dislocation loops and dislocation walls, but also bubbles of water present in the deformed omphacite. The bubbles attach to the dislocation loops which are often connected to one another via a common bubble. Using infrared spectroscopy (IR), two types of hydrous components are identified as hydroxyl and free‐water in the omphacite. An analysis of deformation mechanism of microstructure in omphacite suggests that the mineral deformed plastically under UHP metamorphic conditions by dislocation creep through hydrolitic weakening.