The temperature dependence of the Al2O3 solubility in bridgmanite has been determined in the system MgSiO3–Al_(2)O_(3)at temperatures of 2750–3000 K under a constant pressure of 27 GPa using a multi-anvil apparatus....The temperature dependence of the Al2O3 solubility in bridgmanite has been determined in the system MgSiO3–Al_(2)O_(3)at temperatures of 2750–3000 K under a constant pressure of 27 GPa using a multi-anvil apparatus.Bridgmanite becomes more aluminous with increasing temperatures.A LiNbO3-type phase with a pyrope composition(Mg_(3)Al_(2)Si_(3)O_(12))forms at 2850 K,which is regarded as to be transformed from bridgmanite upon decompression.This phase contains 30 mol%Al_(2)O_(3)at 3000 K.The MgSiO3 solubility in corundum also increases with temperatures,reaching 52 mol%at 3000 K.Molar volumes of the hypothetical Al_(2)O_(3)bridgmanite and MgSiO_(3)corundum are constrained to be 25.950.05 and 26.24±0.06 cm^(3)/mol,respectively,and interaction parameters of non-ideality for these two phases are 5.6±0.5 and 2.2±0.5 KJ/mol,respectively.The increases in Al^(2)O^(3)and MgSiO^(3)contents,respectively,in bridgmanite and corundum are caused by a larger entropy of Al_(2)O_(3)bridgmanite plus MgSiO_(3)corundum than that of MgSiO_(3)bridgmanite plus Al_(2)O_(3)corundum with temperature,in addition to the configuration entropy.Our study may help explain dynamics of the top lower mantle and constrain pressure and temperature conditions of shocked meteorites.展开更多
Water in Earth's mantle plays a critical role in both geodynamic and surficial habitability.Water in the upper mantle and transition zone is widely discussed,but less is known about the water in the lower mantle d...Water in Earth's mantle plays a critical role in both geodynamic and surficial habitability.Water in the upper mantle and transition zone is widely discussed,but less is known about the water in the lower mantle despite it constituting over half of Earth's mass.Understanding the water storage in Earth's lower mantle relies on comprehending the water solubility of bridgmanite,which is the most abundant mineral both in the lower mantle and throughout Earth.Nevertheless,due to limited access to the lower mantle,our understanding of water in bridgmanite mainly comes from laboratory experiments and theoretical calculations,and a huge controversy still exists.In this paper,we provide a review of the commonly employed research methods and current findings concerning the solubility of water in bridgmanite.Potential factors,such as pressure,temperature,compositions,etc.,that influence the water solubility of bridgmanite will be discussed,along with insights into future research directions.展开更多
基金Z.L.was financially supported by the Bayerisches Geoinstitut Visitor’s Program and the Fundamental Research Funds for the Central Universities of Ministry of Education of China(Grant No.45119031C037)This project has received funding from the European Research Council(ERC)under the European Union’s Horizon 2020 research and innovation programme(Proposal No.787527)+2 种基金It is also supported by research grants to T.K.(BMBF:05K13WC2,05K16 WC2DFG:KA3434/3–1,KA3434/7–1,KA3434/8–1,KA3434/9–1)Z.L.(the National Science Foundation of China Grant No.41902034).
文摘The temperature dependence of the Al2O3 solubility in bridgmanite has been determined in the system MgSiO3–Al_(2)O_(3)at temperatures of 2750–3000 K under a constant pressure of 27 GPa using a multi-anvil apparatus.Bridgmanite becomes more aluminous with increasing temperatures.A LiNbO3-type phase with a pyrope composition(Mg_(3)Al_(2)Si_(3)O_(12))forms at 2850 K,which is regarded as to be transformed from bridgmanite upon decompression.This phase contains 30 mol%Al_(2)O_(3)at 3000 K.The MgSiO3 solubility in corundum also increases with temperatures,reaching 52 mol%at 3000 K.Molar volumes of the hypothetical Al_(2)O_(3)bridgmanite and MgSiO_(3)corundum are constrained to be 25.950.05 and 26.24±0.06 cm^(3)/mol,respectively,and interaction parameters of non-ideality for these two phases are 5.6±0.5 and 2.2±0.5 KJ/mol,respectively.The increases in Al^(2)O^(3)and MgSiO^(3)contents,respectively,in bridgmanite and corundum are caused by a larger entropy of Al_(2)O_(3)bridgmanite plus MgSiO_(3)corundum than that of MgSiO_(3)bridgmanite plus Al_(2)O_(3)corundum with temperature,in addition to the configuration entropy.Our study may help explain dynamics of the top lower mantle and constrain pressure and temperature conditions of shocked meteorites.
基金National Science Fund for Distinguished Young Scholars(Grant No.42225302)to Yuan Li。
文摘Water in Earth's mantle plays a critical role in both geodynamic and surficial habitability.Water in the upper mantle and transition zone is widely discussed,but less is known about the water in the lower mantle despite it constituting over half of Earth's mass.Understanding the water storage in Earth's lower mantle relies on comprehending the water solubility of bridgmanite,which is the most abundant mineral both in the lower mantle and throughout Earth.Nevertheless,due to limited access to the lower mantle,our understanding of water in bridgmanite mainly comes from laboratory experiments and theoretical calculations,and a huge controversy still exists.In this paper,we provide a review of the commonly employed research methods and current findings concerning the solubility of water in bridgmanite.Potential factors,such as pressure,temperature,compositions,etc.,that influence the water solubility of bridgmanite will be discussed,along with insights into future research directions.
