Review
Environmental Sciences
Christopher C. C. Finlay, Nicolas Gillet, Julien Aubert, Philip W. W. Livermore, Dominique Jault
Summary: The turbulent motions of liquid metal in Earth's outer core generate the geomagnetic field. Observations and simulations have shown that the present-day core motions are dominated by a planetary-scale gyre, a jet in the northern polar region, and waves involving the magnetic field. In this review, we explore the dynamics of these core features and discuss their impact on the Earth's magnetism and rotation.
NATURE REVIEWS EARTH & ENVIRONMENT
(2023)
Article
Geosciences, Multidisciplinary
Jie Deng, Zhixue Du
Summary: Research suggests that primordial helium in the deep mantle could be continuously supplied from Earth's core through the exsolution of magnesium oxide. This finding has significant implications for understanding Earth's interior processes and the role of the core.
Review
Environmental Sciences
Kei Hirose, Bernard Wood, Lidunka Vocadlo
Summary: Although the exact composition of the Earth's core remains unknown, high-pressure experiments, theoretical calculations, and geological observations can help us estimate the likely range of compositions for the outer and inner core.
NATURE REVIEWS EARTH & ENVIRONMENT
(2021)
Article
Geochemistry & Geophysics
Santiago Andres Triana, Antony Trinh, Jeremy Rekier, Ping Zhu, Veronique Dehant
Summary: The cause of the damping of the Earth's free core nutation and the free inner core nutation eigenmodes has been a debated issue. A 3D numerical model was developed to accurately describe viscous and Ohmic dissipation processes in the Earth's fluid core, showing that most energy is lost at the core-mantle interface. This study validates previous assumptions about energy dissipation.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
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
Geosciences, Multidisciplinary
Yi Yang, Xiaodong Song
Summary: Analysis of repeated seismic waves since the early 1990s indicates that the rotation of Earth's inner core has recently paused and is now reversing, aligning with the multidecadal oscillation of the length of day and magnetic field variations. These findings provide evidence for dynamic interactions between different layers of the Earth, possibly due to the exchange of angular momentum from the core and mantle to the surface.
Article
Environmental Sciences
Ying Zhou
Summary: The differences in travel time between seismic waves generated by two large earthquakes about 20 years apart indicate a localized density change of 2-3% in the Earth's outer core, possibly caused by fast-moving flows rich in light elements.
COMMUNICATIONS EARTH & ENVIRONMENT
(2022)
Article
Multidisciplinary Sciences
Stephan Homrighausen, Kaj Hoernle, Folkmar Hauff, Patrick A. Hoyer, Karsten M. Haase, Wolfram H. Geissler, Jorg Geldmacher
Summary: Recent studies reveal that mantle plumes play a crucial role in transferring material and heat from Earth's interior to its surface through multifaceted upwellings. The Tristan-Gough hotspot track, located in the South Atlantic, has provided evidence of spatial geochemical zonation in two distinct sub-tracks since around 70 million years ago. The origin and sudden appearance of these distinct geochemical flavors are still a mystery, but they could offer valuable insights into the structural evolution of mantle plumes.
NATURE COMMUNICATIONS
(2023)
Article
Geochemistry & Geophysics
Sebastian Rost, Daniel A. Frost, Andy Nowacki, Laura Cobden
Summary: The seismic wavefield carries important information about the seismic source and Earth's structure, but current methods have limitations in resolving fine scale structure. In this study, we show that analyzing slowness vector deviations can help extend our knowledge to smaller scales. By analyzing seismic array data, we were able to detect strong focal and defocal effects of the teleseismic wavefield, providing more insight into the fine scale velocity structure of Earth's interior.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Multidisciplinary Sciences
Yu He, Duck Young Kim, Viktor V. Struzhkin, Zachary M. Geballe, Vitali Prakapenka, Ho-kwang Mao
Summary: Iron hydride in Earth's interior can be formed by the reaction between hydrous minerals and iron. Studying iron hydride enhances our knowledge of hydrogen transportation in Earth's interior. High-pressure experiments have shown that fcc FeHx is stable up to 165 GPa, and molecular dynamics simulations predict a superionic state under lower mantle conditions. This superionic state in fcc FeHx allows highly diffusive-like fluids with a comparable diffusion coefficient to exist, potentially creating a hydrogen reservoir in the outer core.
Article
Geosciences, Multidisciplinary
Frederic Deschamps, Laura Cobden
Summary: The translation introduces a new method to estimate the temperature at Earth's core-mantle boundary using seismic measurements, specifically V(S) and Q(S), which provide constraints on the CMB temperature.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Geochemistry & Geophysics
Surya Pachhai, Michael S. Thorne, Tarje Nissen-Meyer
Summary: Qualitative and quantitative analysis of seismic waveforms can reveal the presence of ultralow-velocity zones (ULVZs) at the core-mantle boundary region, but the mapping of ULVZs is incomplete. Researchers have explored the use of multi-scale sample entropy method to search for ULVZ structures, and found this approach to be potentially effective across a wide range of epicentral distances.
Article
Geochemistry & Geophysics
Bradley J. Peters, Andrea Mundl-Petermeier, Valerie A. Finlayson
Summary: The relationship between the isotopic composition of tungsten and the ratio of rhenium to iridium in lavas from Hawaii and Iceland suggests that these rocks may represent relics of core formation processes. This finding holds significant implications for understanding the formation and evolution of the Earth.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Multidisciplinary Sciences
Guanning Pang, Keith D. Koper, Sin-Mei Wu, Wei Wang, Marine Lasbleis, Garrett Euler
Summary: The texture of Earth's inner core, formed as it solidifies within the fluid outer core, can reveal information about its growth and evolution. By using seismic waves, researchers have observed and modeled the fine-scale heterogeneity of the inner core, which shows increased scattering strength at deeper levels. This enhanced scattering is consistent with a period of rapid growth following delayed nucleation.
Article
Geosciences, Multidisciplinary
Kang Wei Lim, Irene Bonati, John W. Hernlund
Summary: We investigate the mechanism of conveying chemical signatures from the core to the mantle through dynamic topography, porous infiltration of liquid metal, gravitational collapse of metal-silicate mush, and induced small-scale mantle circulation.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geochemistry & Geophysics
Mingming Li
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2020)
Article
Geochemistry & Geophysics
Yongming Wang, Mingming Li
Summary: The interaction between mantle plumes and lithosphere leads to various surface expressions, which are influenced by the properties of the plume and lithosphere. Different surface features have different sensitivities to these properties, with melt production being most affected by plume properties.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Multidisciplinary Sciences
Wenzhong Wang, Jiachao Liu, Feng Zhu, Mingming Li, Susannah M. Dorfman, Jie Li, Zhongqing Wu
Summary: Recent studies have shown that the presence of Fe3+-rich bridgmanite in the lowermost mantle can explain the formation of LLSVPs and have significant implications for the storage of redox-sensitive elements in the deep Earth.
NATURE COMMUNICATIONS
(2021)
Article
Geochemistry & Geophysics
Mingming Li, Allen K. McNamara
Summary: Through geodynamic modeling experiments, it was found that thick subducted oceanic crust could form thermochemical piles with a height of up to approximately 1000 km above the core-mantle boundary, with chemically fuzzy top boundaries and stratified interiors. As the oceanic crust thins, it becomes more difficult to accumulate at the core-mantle boundary, leading to smaller accumulations with sharp top boundaries and more homogeneous interiors.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Surya Pachhai, Mingming Li, Michael S. Thorne, Jan Dettmer, Hrvoje Tkalcic
Summary: Studies reveal that ultralow-velocity zones beneath the Coral Sea exhibit stratified density increases and shear-wave velocity decreases, which may be related to remnants of Earth's early differentiation.
Editorial Material
Multidisciplinary Sciences
Allen K. McNamara
Summary: This article discusses the contradiction between ancient records of Earth's magnetic field and the formation of volcanic activity regions, and proposes a statistical modeling approach to reconcile these data.
Article
Geosciences, Multidisciplinary
Qian Yuan, Mingming Li
Summary: The seismic anomaly in the lowermost mantle beneath Africa is higher and less stable than its Pacific counterpart due to its lower density. This suggests that the two anomalies have different compositions, dynamics, and evolution histories.
Article
Geosciences, Multidisciplinary
Byeongkwan Ko, Stella Chariton, Vitali Prakapenka, Bin Chen, Edward J. Garnero, Mingming Li, Sang-Heon Shim
Summary: This study investigates the exchange of water and carbon between the mantle and core, and finds that water can extract carbon from the core in the form of diamond, while the core gains hydrogen. This suggests a link between Earth's deep water and carbon cycles, and extracted core carbon can explain a portion of mantle carbon.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Qian Yuan, Mingming Li
Summary: Two large low velocity provinces (LLVPs) are observed in Earth's lower mantle, beneath Africa and the Pacific Ocean, respectively. The height difference between the African and Pacific LLVPs remains unclear. This study suggests that rapid sinking of stagnant slabs to the lowermost mantle can cause significant height increases of nearby thermochemical piles. The African LLVP may have been pushed more strongly and longer by surrounding mantle flows, resulting in a shallower depth compared to the Pacific LLVP.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Mingming Li
Summary: Mantle plumes are deflected by surrounding mantle flow, which carries information of deep mantle dynamics and is used to reconstruct absolute plate motions. This study compares two models for computing deep mantle flow and plume lateral motions and finds that backward models have certain inaccuracies that can be improved with better understanding of the deep mantle structure and dynamics.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Mingming Li, Stephen Puetz, Kent Condie, Peter Olson
Summary: About 40% of Earth's surface is covered by continental crust. The global detrital zircon age distribution shows periodic growth of continental crust, but the cause of this periodicity remains unclear.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Multidisciplinary Sciences
Samantha E. Hansen, Edward J. Garnero, Mingming Li, Sang-Heon Shim, Sebastian Rost
Summary: Using a new seismic analysis approach, researchers have identified widespread and variable ultralow velocity zones (ULVZs) beneath a largely unsampled area in the Southern Hemisphere. Their study suggests that the accumulation of previously subducted materials on the core-mantle boundary (CMB) could explain the origin of ULVZs, and that these subducted materials can be globally distributed throughout the lowermost mantle with varying concentrations. The discovery provides insights into the distribution and characteristics of ULVZs.
Article
Geochemistry & Geophysics
Jonathan Wolf, Maureen D. Long, Mingming Li, Edward Garnero
Summary: This study utilizes a global digital database to examine the seismic anisotropy distribution in the D '' layer of Earth's mantle and assess whether it is more likely to be located at the edges of the two large-low velocity provinces. The findings indicate that this hypothesis lacks statistical justification when considering previous observations of lowermost mantle anisotropy. The study also highlights the uneven global ray coverage of the lowermost mantle, with the edges and interiors of LLVPs being less well-sampled.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2023)
Article
Geochemistry & Geophysics
Mingming Li
Summary: This study utilizes 3D high-resolution geodynamic models to investigate the dynamics of subducted oceanic crust (SOC) in the lowermost mantle. The segregation and accumulation of SOC near the core-mantle boundary (CMB) are found to be greatly influenced by the morphology of the subducted slab. SOC segregation is more efficient when the slab is folded backward and extends beneath the subducting plate, allowing direct contact with the CMB. Changes in slab morphology result in significant temporal and spatial variations in SOC distribution at the CMB and within the lowermost mantle, explaining the variations of seismic anomalies outside the large-low velocity provinces (LLVPs).
PHYSICS OF THE EARTH AND PLANETARY INTERIORS
(2023)
