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Water solubility in majoritic garnet in subducting oceanic crust
Author(s) -
Katayama Ikuo,
Hirose Kei,
Yurimoto Hisayoshi,
Nakashima Satoru
Publication year - 2003
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 - 10.1029/2003gl018127
Subject(s) - geology , oceanic crust , geochemistry , basalt , crust , underplating , omphacite , mantle (geology) , silicate , mineralogy , subduction , chemistry , eclogite , tectonics , paleontology , organic chemistry
Water in majoritic garnet synthesized in the mid‐oceanic ridge basalt (MORB) + H 2 O composition at 20 GPa and 1400–1500°C was measured by secondary ion mass spectrometry (SIMS) and infrared spectroscopy. We found that the majorite contains 1130 to 1250 ppm OH by weight. The infrared absorption band showed that incorporation of the hydroxyl in majorite is most likely due to the hydrogarnet substitution. Our results indicate that water can be transported into the mantle transition zone by nominally anhydrous minerals such as omphacite and majorite in the subducting basaltic crust. Such water may have great influences on the physical properties of slab in the transition zone.