The role of water in Earth’s mantle  

作　　者：Eiji Ohtani 

机构地区：[1]Graduate School of Science, Tohoku University

出　　处：《National Science Review》2020年第1期224-232,共9页国家科学评论（英文版）

基　　金：supported by KAKENHI from JSPS(15H05748)to E.O.;performed under the contracts of the SPring-8(2017B1514,2018A1425,2018A1447 and2018B1326)

摘　　要：Geophysical observations suggest that the transition zone is wet locally.Continental and oceanic sediment components together with the basaltic and peridotitic components might be transported and accumulated in the transition zone.Low-velocity anomalies at the upper mantle–transition zone boundary might be caused by the existence of dense hydrous magmas.Water can be carried farther into the lower mantle by the slabs.The anomalous Q and shear wave regions locating at the uppermost part of the lower mantle could be caused by the existence of fluid or wet magmas in this region because of the water-solubility contrast between the minerals in the transition zone and those in the lower mantle.δ-H solid solution AlO2H–MgSiO4H2 carries water into the lower mantle.Hydrogen-bond symmetrization exists in high-pressure hydrous phases and thus they are stable at the high pressures of the lower mantle.Thus,the δ-H solid solution in subducting slabs carries water farther into the bottom of the lower mantle.Pyrite FeO2Hx is formed due to a reaction between the core and hydrated slabs.This phase could be a candidate for the anomalous regions at the core–mantle boundary.Geophysical observations suggest that the transition zone is wet locally. Continental and oceanic sediment components together with the basaltic and peridotitic components might be transported and accumulated in the transition zone. Low-velocity anomalies at the upper mantle–transition zone boundary might be caused by the existence of dense hydrous magmas. Water can be carried farther into the lower mantle by the slabs. The anomalous Q and shear wave regions locating at the uppermost part of the lower mantle could be caused by the existence of fluid or wet magmas in this region because of the water-solubility contrast between the minerals in the transition zone and those in the lower mantle. δ-H solid solution AlO2H–MgSiO4H2 carries water into the lower mantle. Hydrogen-bond symmetrization exists in high-pressure hydrous phases and thus they are stable at the high pressures of the lower mantle. Thus, theδ-H solid solution in subducting slabs carries water farther into the bottom of the lower mantle. Pyrite FeO2Hx is formed due to a reaction between the core and hydrated slabs. This phase could be a candidate for the anomalous regions at the core–mantle boundary.

关 键 词：WATER HYDROUS phase subducting SLAB transition zone lower MANTLE HYDROGEN-BOND SYMMETRIZATION core–mantle boundary 

分 类 号：P542.5[天文地球—构造地质学] P592[天文地球—地质学]