Article
Chemistry, Physical
Carla Lupo, Evan Sheridan, Edoardo Fertitta, David Dubbink, Chris J. Pickard, Cedric Weber
Summary: Using spin-assisted ab initio random structure searches, this study explores a comprehensive quantum phase diagram of archetypal interfaced Mott insulators, revealing that charge transfer induced by interfacial electronic reconstruction stabilizes high-spin and low-spin ferrous Fe2+ states. Tuning epitaxial strain allows for control over electronic state correlations, leading to a variety of quantum electronic phases. Additionally, the relationship between electronic correlations and oxygen octahedral rotations is explored, providing potential avenues for magnetic switching via THz radiations with implications for the future of spintronics technologies.
NPJ COMPUTATIONAL MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Kaishuai Yang, Xianlong Wang, Jie Zhang, Ya Cheng, Chuanguo Zhang, Zhi Zeng, Haiqing Lin
Summary: The distribution of Fe in MgO plays a critical role in broadening the spin crossover pressure zone, with varied SCPZ depending on Fe concentration. Below a critical temperature, Fe segregation occurs, while above this temperature, entropy-driven randomized Fe distribution leads to broadening of SCPZ, consistent with the high-temperature state of the lower mantle.
Article
Physics, Applied
Sourav Kanthal, Pradip Manna, Ashok Das, Giuliana Aquilanti, Aritra Banerjee, Sudipta Bandyopadhyay
Summary: This study investigates the magnetic properties of Ni doped NdCufr and compares them with pristine and Co doped NdCufr. The results of the investigation show the advantages of doping and provide a detailed understanding of the role of magnetic interactions in modulating the magnetic behavior.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Geochemistry & Geophysics
Ashim Rijal, Laura Cobden, Jeannot Trampert, Jennifer M. Jackson, Andrew Valentine
Summary: This study uses neural network techniques to infer the physical properties of MgO and finds good constraints on its elastic properties through experimental data, but uncertainties exist in low pressure high temperature and high temperature regions. Comparing with different forms of equation of state as a potential bias source in uncertainty quantification is highlighted in mineral seismic properties interpretations.
PHYSICS OF THE EARTH AND PLANETARY INTERIORS
(2021)
Article
Physics, Applied
Tao Liang, Fei Zhang, Xin Zhang, Xiehang Chen, Songyi Chen, Hongbo Lou, Zhidan Zeng, Dazhe Xu, Ke Yang, Yuming Xiao, Paul Chow, Baolong Shen, Qiaoshi Zeng
Summary: The study investigates the pressure effect on Fe78Si9B13 metallic glass at high pressures up to around 51GPa, revealing a reversible and continuous pressure-induced high- to low-spin crossover of Fe atoms in an amorphous structure. The changes of the local spin moment can be scaled to match its average atomic distance shrinkage very well during compression.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Multidisciplinary Sciences
V Baledent, L. Nataf, J-P Rueff
Summary: This study investigates the structural and magnetic stability of SrFeO2 under high pressure using XMCD and XRD techniques. The results show that SrFeO2 maintains its structural integrity and exhibits strong magnetic stability under extreme pressure conditions.
SCIENTIFIC REPORTS
(2022)
Article
Geochemistry & Geophysics
Fei Wang, Hongzhan Fei, Lin Wang, Catherine Mccammon, Daniel J. Frost, Tomoo Katsura
Summary: A study found that the Fe oxidation state in Bridgmanite in the lower mantle decreases with increasing temperature, suggesting that the level of charge disproportionation may have been lower in the early Earth's high-temperature conditions. However, if the redox state in the upper lower mantle is buffered by coexisting iron and ferropericlase, the relative oxygen fugacity would have changed very little during long-term cooling.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
A. S. J. Mendez, S. Stackhouse, V Trautner, B. Wang, N. Satta, A. Kurnosov, R. J. Husband, K. Glazyrin, H-P Liermann, H. Marquardt
Summary: The study reveals the elastic bulk modulus softening of (Mg,Fe)O ferropericlase across the iron spin crossover and its significant impact on the physical properties. Experimental and computational results show that the softening effect is sensitive to the distribution of iron in the ferropericlase structure. Mixed-spin (Mg,Fe)O dominates the lower mantle at depths below 1,000 km.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Materials Science, Multidisciplinary
Zhen Zhang, Dong-Bo Zhang, Kotaro Onga, Akira Hasegawa, Kenji Ohta, Kei Hirose, Renata M. Wentzcovitch
Summary: The thermal conductivity (κ) of mantle minerals plays a crucial role in understanding deep Earth dynamics, with cubic CaSiO3 perovskite being the third most abundant mineral in the lower mantle. Experimental and theoretical studies show that the unexpectedly high κ of CaPv significantly affects the overall mantle κ, impacting regions enriched in subducted crustal materials.
Article
Chemistry, Physical
Vivek Dhand, Hyunho Shin, Gyeonghun Han, S. Bharadwaj, Kyongyop Rhee, Sanghoon Kim
Summary: The study found that the oxygen-deficient perovskite-type barium iron oxide/polydimethylsiloxane composite material exhibits unique magnetic properties, with PDMS completely encapsulating the BaFeO3-delta powder.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Geochemistry & Geophysics
Margo E. Regier, Karen V. Smit, Thomas B. Chalk, Thomas Stachel, Richard A. Stern, Evan M. Smith, Gavin L. Foster, Yannick Bussweiler, Chris DeBuhr, Antony D. Burnham, Jeff W. Harris, D. Graham Pearson
Summary: The isotopic composition of boron in blue diamonds indicates a potential subduction pathway for volatile elements into the deep mantle, possibly originating from subducted oceanic lithosphere. This finding reveals the process of volatile elements entering the deep mantle through deep material subduction.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Bijoy Dey, Jordi Cirera, Sakshi Mehta, Liliana P. Ferreira, Ramar Arumugam, Abhishake Mondal, Paulo N. Martinho, Vadapalli Chandrasekhar
Summary: Steric effects of ligand substituents on Fe(III) complexes were investigated, revealing that larger substituents maintain a high-spin state while smaller substituents exhibit spin-crossover behavior, due to the distortion of the complex structure.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Geosciences, Multidisciplinary
Jun Hu, Liangxu Xu, Jin Liu, Donghui Yue
Summary: The high-pressure behavior of deep carbonate plays a vital role in the global carbon cycle and potentially influencing long-term climate change. Optical and vibrational properties of carbonate minerals are highly correlated with iron content and spin transition, shedding new light on the evolution of carbonate minerals in the mantle. These results are crucial for decoding the deep carbon cycle.
ACTA GEOLOGICA SINICA-ENGLISH EDITION
(2023)
Article
Multidisciplinary Sciences
Qingyang Hu, Jin Liu, Jiuhua Chen, Bingmin Yan, Yue Meng, Vitali B. Prakapenka, Wendy L. Mao, Ho-Kwang Mao
Summary: The mineralogical transformations in the deep lower mantle under high pressure-temperature conditions with the presence of water were investigated. A previously unknown (Mg,Fe)O2Hx phase was discovered, storing excessive oxygen beyond the charge balance of maximum cation valences. This phase has important implications for extreme redox inhomogeneity, deep-oxygen reservoirs in the lower mantle, and modulating oxygen in the atmosphere.
NATIONAL SCIENCE REVIEW
(2021)
Article
Chemistry, Inorganic & Nuclear
Shu-Ya Zhang, Hui-Ying Sun, Run-Guo Wang, Yin-Shan Meng, Tao Liu, Yuan-Yuan Zhu
Summary: The self-assembly of multinuclear SCO complexes is appealing for the discovery of unique properties. In this work, three dinuclear cobalt(II) complexes were prepared using a complementary terpyridine ligand pair strategy. The complexes show different spin crossover behaviors and demonstrate the practicality of the complementary terpyridine ligand pairing in constructing multinuclear SCO-active compounds.
DALTON TRANSACTIONS
(2022)
Article
Geochemistry & Geophysics
Wenzhong Wang, Han Zhang, John P. Brodholt, Zhongqing Wu
Summary: The mantle transition zone (MTZ) is potentially a geochemical water reservoir due to the high H2O solubility in its dominant minerals. The water content in the MTZ is crucial for understanding deep-water distribution, geochemical recycling, and mantle convection patterns. High-pressure, high-temperature conditions were found to enhance the hydration effect on ringwoodite velocities, with water content affecting elastic moduli and velocities.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geochemistry & Geophysics
Yunguo Li, Lidunka Vocadlo, Amy Edgington, John P. Brodholt
Summary: Ab initio molecular dynamics simulations were used to determine equations of state for CO and CO2 fluids, with a focus on the polymerisation effect and how it impacts the accuracy of EOS. Caution is advised when extrapolating EOS determined by traditional methods beyond tested pressures and temperatures. Additionally, thermodynamic calculations for decarbonation reactions using the derived CO2 EOS showed good agreement with experimental and theoretical data at low pressures.
Article
Geochemistry & Geophysics
David P. Dobson, Leny Montheil, Joseph J. Paine, Andrew R. Thomson
Summary: Pseudotachylites are formed by flash melting of fusible minerals, with compositions dominated by biotite mica. Phase fraction calculations suggest that their matrix compositions cannot be reproduced by a simple linear mixture of host rock minerals and often show a potassium deficit, indicating peritectic melting of mica under fluid-absent conditions or fluid-present conditions in some cases. Fluid-absent flash melting appears to be the most common mode of pseudotachylite formation, but fluid presence can also play a role.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Geochemistry & Geophysics
Andrew R. Thomson, Ross O. Piltz, Wilson A. Crichton, Valerio Cerantola, Isra S. Ezad, David P. Dobson, Ian G. Wood, John P. Brodholt
Summary: Hydrous Fo(91) ringwoodite crystals were synthesized at high pressure and high temperature, and analyzed using various techniques to characterize their chemistry and crystallography. The presence of tetrahedrally coordinated ferric iron and multiple hydrogen incorporation mechanisms were observed in these blue-colored iron-bearing ringwoodite crystals. This may have implications for the seismic velocities within the Earth's transition zone and the coloration of high-pressure crystals like ringwoodite.
AMERICAN MINERALOGIST
(2021)
Article
Geochemistry & Geophysics
Joshua M. R. Muir, Feiwu Zhang, John P. Brodholt
Summary: This study investigates the transition of ringwoodite to other minerals using density functional theory, and shows that the addition of water significantly affects the properties of the transition zone and leads to a broadening of the transition.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geochemistry & Geophysics
Wenzhong Wang, Yunguo Li, John P. Brodholt, Lidunka Vocadlo, Michael J. Walter, Zhongqing Wu
Summary: Research using ab initio molecular dynamic simulations shows that hydrogen-bearing iron and iron-silicon alloys maintain a superionic state under inner-core conditions, resulting in strong shear softening of their shear moduli. Several compositions of hcp-iron-silicon-hydrogen can explain the observed density, velocity, and Poisson's ratio of the inner core simultaneously. This suggests that hydrogen is a significant component of Earth's core and indicates that Earth may have accreted water from chondritic and/or nebular materials before or during core formation.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Wenzhong Wang, Chun-Hui Li, John P. Brodholt, Shichun Huang, Michael J. Walter, Min Li, Zhongqing Wu, Fang Huang, Shui-Jiong Wang
Summary: Earth's volatile element content was largely established by volatile evaporation from molten planetesimals before Earth's formation, as indicated by sulfur isotope fractionation analysis and first-principles calculations.
Article
Geochemistry & Geophysics
James W. E. Drewitt, Michael J. Walter, John P. Brodholt, Joshua M. R. Muir, Oliver T. Lord
Summary: In this study, ab initio atomistic simulations of hydrous silicate melts under different mantle conditions were performed and used to parameterize density and viscosity in the MgO-SiO2-H2O ternary system. The results show that hydrous melts in the mantle transition zone will have positive buoyancy and low viscosity. Box models of mantle circulation indicate that the upper mantle becomes efficiently hydrated during upward mobility of melts in the transition zone, making it difficult to maintain large differences in water concentration between the upper mantle, transition zone, and lower mantle. The water content of the transition zone and lower mantle is estimated to be similar to 0.02-0.04 wt%, resulting in a bulk mantle water content of approximately 0.5 to 1 ocean mass.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geosciences, Multidisciplinary
D. Huang, J. Brodholt, P. Sossi, Y. Li, M. Murakami
Summary: This study investigates the speciation of nitrogen in anhydrous and hydrous pyrolitic melts under varying pressure, temperature, and redox conditions. It is found that under oxidizing conditions, nitrogen forms N-N bonding at lower mantle pressures, while under reducing conditions, it interacts with the silicate network or forms N-H bonds. The redox control of nitrogen speciation is demonstrated to be valid over a range of pressure-temperature conditions, potentially influencing the composition of secondary atmospheres on Earth.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
F. Xu, D. Yamazaki, S. A. Hunt, N. Tsujino, Y. Higo, Y. Tange, K. Ohara, D. P. Dobson
Summary: This study experimentally verifies the rheology control of bridgmanite under low strain magnitude. The results demonstrate that bridgmanite dominates the bulk viscosity of post-spinel without strain localization and provides direct evidence for geodynamical models considering mantle compositional and rheological evolution in the lower mantle.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Multidisciplinary Sciences
Yunguo Li, Lidunka Vocadlo, Chris Ballentine, John P. P. Brodholt
Summary: Ab initio calculations were performed to determine the partitioning of noble gases between liquid iron and silicate melt under core forming conditions. The results showed significant differences in the partition coefficients of helium and neon, indicating that the core could contain substantial amounts of helium but not neon. Therefore, the core is not the source of noble gases in ocean island basalts.
NATURE COMMUNICATIONS
(2022)
Article
Geochemistry & Geophysics
Isra S. Ezad, David P. Dobson, Andrew R. Thomson, Eleanor S. Jennings, Simon A. Hunt, John P. Brodholt
Summary: In this study, high-pressure and high-temperature experiments were conducted to investigate the breakdown of garnet in the spinel-lherzolite stability field. The results showed that cascading reactions can reproduce the multilayer, multiphase kelyphites observed in nature. The experiments also confirmed the importance of melts in moderating the reactions towards equilibrium. These findings challenge the assumption that kelyphites are caused by a multistage uplift path and provide insights into the kinetics of garnet breakdown reactions.
JOURNAL OF PETROLOGY
(2022)
Article
Mineralogy
Jeffrey P. Gay, Lowell Miyagi, Samantha Couper, Christopher Langrand, David P. Dobson, Hanns-Peter Liermann, Sebastien Merkel
Summary: The deformation, phase transformation, and texture development of the perovskite analogue NaCoF3 were studied under high pressure and high temperature conditions. A phase transition from perovskite to post-perovskite was observed between 20.1 and 26.1 GPa, accompanied by a decrease in stress. X-ray diffraction was used to monitor the crystal structure and texture, providing insights into microstructure development in the Earth's mantle.
EUROPEAN JOURNAL OF MINERALOGY
(2021)
Article
Geochemistry & Geophysics
Simon A. Hunt, James R. Santangeli, David P. Dobson, Ian G. Wood
Summary: The MgGeO3 system serves as a low-pressure analog for the Earth-forming system and demonstrates recoverable orthopyroxene, clinopyroxene, and ilmenite structures. There are discrepancies in the phase transitions within existing works, mainly attributed to different methods used. High-pressure and -temperature experiments show consistent results for the orthopyroxene-clinopyroxene phase transition in MgGeO3.
AMERICAN MINERALOGIST
(2021)
Article
Geochemistry & Geophysics
Lingyu Zhang, Kristoffer Szilas
Summary: This study presents new petrological and geochemical data for the Narssaq Ultramafic Body (NUB) in the Itsaq Gneiss Complex of SW Greenland. The results indicate that the ultramafic rocks of NUB are not mantle residues, but instead represent crustal cumulates derived from high-Mg magmas.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Rong Xu, Sarah Lambart, Oliver Nebel, Ming Li, Zhongjie Bai, Junbo Zhang, Ganglan Zhang, Jianfeng Gao, Hong Zhong, Yongsheng Liu
Summary: This study investigated the iron isotope compositions of Cenozoic basalts in Southeast China, finding significant variations related to different types of basalts and their respective sources.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
C. J. Ebinger, Miriam C. Reiss, Ian Bastow, Mary M. Karanja
Summary: The East African rift system is formed above mantle upwellings and the formation of rifts is related to lithospheric thinning and magmatic activity. The amount of splitting varies spatially and the fast axes are predominantly parallel to the orientation of the rifts. Thick lithospheric modules have less splitting and different orientations, which may indicate mantle plume flow. Splitting rotates and increases in strength as it enters the rift zones, suggesting that the anisotropy is mainly present at shallow depths.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Correction
Geochemistry & Geophysics
Ekaterina Rojas-Kolomiets, Owen Jensen, Michael Bizimis, Gene Yogodzinski, Lukas Ackerman
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Robert W. Nicklas, Igor S. Puchtel, Ethan F. Baxter
Summary: Oxygen fugacity is a fundamental parameter for understanding redox processes in igneous systems. This study compares the Fe-XANES oxybarometry method with the V-in-olivine method for evaluating fO(2) in MORB lavas. The results show that the V-in-olivine method is not applicable to samples with low MgO content, and that the majority of Archean komatiite sources have lower fO(2) than modern MORB.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Chunfei Chen, Stephen F. Foley, Sebastian Tappe, Huange Ren, Lanping Feng, Yongsheng Liu
Summary: The volatile components CO2 and H2O play a major role in mantle melting and heterogeneity. In this study, Ca isotopes were used to trace the lithological heterogeneity in alkaline magmatic rocks. The results revealed the presence of K-richterite and carbonate components as the source of alkaline magmas with low delta 44/40Ca values. These findings highlight the importance of Ca isotopes as a robust tracer of lithological variation caused by volatiles in the Earth's upper mantle.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Timothee Jautzy, Gilles Rixhon, Regis Braucher, Romain Delunel, Pierre G. Valla, Laurent Schmitt, Aster Team
Summary: Although the current approach to estimate catchment-wide denudation rates using only 10Be concentrations has made significant progress in geomorphology, this study argues for the inclusion of 26Al measurements and testing of steady-state assumptions in slow eroding, formerly glaciated landscapes. The study conducted measurements of both 10Be and 26Al in stream sediments from the Vosges Massif in France and found that elevation, slope, channel steepness, and precipitation were the primary factors controlling denudation rates. The study also revealed a significant relationship between the extent of past glaciation and the cosmogenic (un-)steadiness in the stream sediments.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Erik van der Wiel, Douwe J. J. van Hinsbergen, Cedric Thieulot, Wim Spakman
Summary: Numerical models of Earth's mantle dynamics can predict the vigour and mixing of mantle flow, and the average slab sinking rates are an unexplored parameter that can provide intrinsic information on these characteristics. Through numerical experiments, it has been found that slab sinking rates are strongly correlated with mantle convection and mixing, and may explain geochemical observations from hotspot volcanoes.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)