Slab dehydration in the Earth's mantle transition zone

2006 ◽  
Vol 251 (1-2) ◽  
pp. 156-167 ◽  
Author(s):  
Guillaume Richard ◽  
David Bercovici ◽  
Shun-Ichiro Karato
Keyword(s):  
Transition Zone ◽  
Mantle Transition Zone ◽  
Earth’S Mantle ◽  
Slab Dehydration

scholarly journals Tracing the subducting Pacific slab to the mantle transition zone with hydrogen isotopes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takeshi Kuritani ◽  
Kenji Shimizu ◽  
Takayuki Ushikubo ◽  
Qun-Ke Xia ◽  
Jia Liu ◽  
...  
Keyword(s):  
Transition Zone ◽  
Melt Inclusions ◽  
Hydrogen Isotopes ◽  
Volcanic Front ◽  
Mantle Transition Zone ◽  
Deep Interior ◽  
Terrestrial Water ◽  
Quantitative Understanding ◽  
Pacific Slab ◽  
Slab Dehydration

AbstractHydrogen isotopes have been widely used as powerful tracers to understand the origin of terrestrial water and the water circulation between the surface and the deep interior of the Earth. However, further quantitative understanding is hindered due to a lack of observations about the changes in D/H ratios of a slab during subduction. Here, we report hydrogen isotope data of olivine-hosted melt inclusions from active volcanoes with variable depths (90‒550 km) to the subducting Pacific slab. The results show that the D/H ratio of the slab fluid at the volcanic front is lower than that of the slab fluid just behind the volcanic front. This demonstrates that fluids with different D/H ratios were released from the crust and the underlying peridotite portions of the slab around the volcanic front. The results also show that the D/H ratios of slab fluids do not change significantly with slab depths from 300 to 550 km, which demonstrates that slab dehydration did not occur significantly beyond the arc. Our estimated δD‰ value for the slab materials that accumulated in the mantle transition zone is > − 90‰, a value which is significantly higher than previous estimates.

scholarly journals High-pressure phase of brucite stable at Earth’s mantle transition zone and lower mantle conditions

2016 ◽  
Vol 113 (49) ◽  
pp. 13971-13976 ◽  
Author(s):  
Andreas Hermann ◽  
Mainak Mookherjee
Keyword(s):  
High Pressure ◽  
Transition Zone ◽  
Lower Mantle ◽  
Direct Detection ◽  
Geophysical Methods ◽  
High Pressure Phase ◽  
Mantle Transition Zone ◽  
Earth’S Mantle ◽  
3D Network ◽  
Pressure Phase

We investigate the high-pressure phase diagram of the hydrous mineral brucite, Mg(OH)2, using structure search algorithms and ab initio simulations. We predict a high-pressure phase stable at pressure and temperature conditions found in cold subducting slabs in Earth’s mantle transition zone and lower mantle. This prediction implies that brucite can play a much more important role in water transport and storage in Earth’s interior than hitherto thought. The predicted high-pressure phase, stable in calculations between 20 and 35 GPa and up to 800 K, features MgO6 octahedral units arranged in the anatase–TiO2 structure. Our findings suggest that brucite will transform from a layered to a compact 3D network structure before eventual decomposition into periclase and ice. We show that the high-pressure phase has unique spectroscopic fingerprints that should allow for straightforward detection in experiments. The phase also has distinct elastic properties that might make its direct detection in the deep Earth possible with geophysical methods.

Phase transformations of Ca3Al2Si3O12 grossular garnet to the depths of the Earth's mantle transition zone

2011 ◽  
Vol 185 (3-4) ◽  
pp. 89-99 ◽  
Author(s):  
Steeve Gréaux ◽  
Norimasa Nishiyama ◽  
Yoshio Kono ◽  
Laurent Gautron ◽  
Hiroaki Ohfuji ◽  
...  
Keyword(s):  
Phase Transformations ◽  
Transition Zone ◽  
Mantle Transition Zone ◽  
Earth’S Mantle ◽  
Grossular Garnet

scholarly journals Rheology of Mg2 GeO4 olivine and spinel harzburgite: Implications for Earth's mantle transition zone

2015 ◽  
Vol 42 (7) ◽  
pp. 2212-2218 ◽  
Author(s):  
F. Shi ◽  
J. Zhang ◽  
G. Xia ◽  
Z. Jin ◽  
H. W. Green
Keyword(s):  
Transition Zone ◽  
Mantle Transition Zone ◽  
Earth’S Mantle
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