Article
Geochemistry & Geophysics
Zheng Tang, Jordi Julia, Walter D. Mooney, Paul Martin Mai, Huazhi Yu, Yanqiang Wu
Summary: We provide a comprehensive image of the mantle transition zone beneath northeastern China, revealing fine-scale topography and lateral variations in thickness and slab interfaces within the zone. The images provide direct evidence for the presence of the stagnant Pacific subducting slab and support previous hypotheses of mantle upwelling triggered by the sinking of the stagnant slab.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Youqiang Yu, Zhiguo Xu, Stephen S. Gao, Kelly H. Liu, Jia Gao
Summary: The South China Sea is a hydrocarbon-rich major marginal sea in the western Pacific Ocean. Its formation may have been driven by slab-pull, with evidence of significant thickening of the subducted slab beneath the southern margin, supporting the existence of the Proto-South China Sea. Chemically and rheologically heterogeneous materials from the slab segments may have generated layered structures and dehydration melting.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geochemistry & Geophysics
Lin Liu, Sanzhong Li
Summary: This study utilizes a large amount of seismic data to reveal the details of the two opposite dipping subduction zones near Taiwan, as well as analyze the structure and influencing factors of the mantle transition zone.
Article
Geochemistry & Geophysics
Dongyang Liu, Liang Zhao, Anne Paul, Huaiyu Yuan, Stefano Solarino, Coralie Aubert, Silvia Pondrelli, Simone Salimbeni, Elena Eva, Marco G. Malusa, Stephane Guillot
Summary: By studying the mantle transition zone structure in the Western Alps using P-wave receiver functions, it was found that the MTZ thickened by about 40 km under the Western Alps and Po Plain, associated with uplift and depression caused by the 410-km and 660-km discontinuities. The thick MTZ was attributed to the subduction of the Alpine slab and remnants of subducted oceanic lithosphere, providing evidence of the subduction depth of the Western Alps slab.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Takayuki Ishii, Eiji Ohtani
Summary: Research suggests that even under wet subducting slab conditions, olivine and wadsleyite exhibit dry transformation kinetics, which could contribute to deep-focus earthquakes and large slab deformation.
Article
Geosciences, Multidisciplinary
Xiaoming Xu, Zhifeng Ding, Fenglin Niu
Summary: We calculated a large number of receiver functions from teleseismic events recorded by two seismic arrays in the TNCO and NCC regions. After moveout correction, the CCP stacking method was used to image the structures of the MTZ. The topographic variations of the 410km and 660-km discontinuities across the study area were observed. The results provide new insights into the mantle dynamics and tectonic evolution in the TNCO and NCC regions.
JOURNAL OF ASIAN EARTH SCIENCES
(2023)
Article
Geochemistry & Geophysics
Lin Wang, Artem Chanyshev, Nobuyoshi Miyajima, Takaaki Kawazoe, Stephan Blaha, Jia Chang, Tomoo Katsura
Summary: This study investigates the effect of water content on upper mantle dynamics by measuring the annihilation rate coefficients of a-dislocations and c-dislocations in olivine. The results suggest that water has a limited overall effect on dislocation mobility and does not effectively increase the dislocation creep rate. Additionally, a water-induced fabric transition is unlikely to occur.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Erin Heilman, Thorsten W. Becker
Summary: Mantle plumes can play a significant role in the evolution of Earth and plate tectonics, potentially causing the termination of subduction zones and contributing to the complexity of mantle structures. This effect may be particularly relevant for the early Earth and remain relevant in modern times.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Han Zhang, Brandon Schmandt, Jin S. Zhang
Summary: The measurement of anisotropy using seismic observations and constraints from mineral physics has advanced our understanding of mantle dynamics. In the Pacific Northwest, significant depth-integrated anisotropic signals have been recorded, likely due to mantle flow focusing through slab gaps leading to locally elevated stress.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Gaurav Kumar, Arun Singh, Ashwani Kant Tiwari, Chandrani Singh, M. Ravi Kumar, Dipankar Saikia, Mita Uthaman, Arun Kumar Dubey
Summary: We mapped the depth variations of d410 and d660 beneath the Sikkim Himalaya and adjoining regions using 18,816 P wave receiver functions. The average variations for d410 and d660 in the entire study region were found to be 395 +/- 4 km and 652 +/- 5 km, respectively, with a similar mantle transition zone thickness of 255 km. The upliftment in the upper mantle discontinuities reflects the presence of a thick Indian lithosphere beneath the study region.
JOURNAL OF ASIAN EARTH SCIENCES
(2023)
Article
Environmental Sciences
Gilbert L. Mao, Thomas P. Ferrand, Jiaqi Li, Brian Zhu, Ziyi Xi, Min Chen
Summary: The study investigates the triggering mechanism of deep-focus earthquakes through the b value analysis, specifically focusing on the western Pacific Plate. A transition in b values is observed at magnitude 3.7-3.8 in the Honshu and Izu deep seismicity, indicating enhanced transformational faulting possibly catalyzed by deep hydrous defects near the unstable rim of the metastable olivine wedge.
COMMUNICATIONS EARTH & ENVIRONMENT
(2022)
Article
Geochemistry & Geophysics
Jingchuan Wang, Yu Jeffrey Gu
Summary: The morphology and composition of subducted slabs in the upper mantle transition zone have direct implications for mantle convection. Investigating the seismic reflectivity structure beneath South America, researchers found broad regions with depressed discontinuities and diminished precursor amplitudes beneath the back-arc region of Nazca subduction. Probabilistic inversion and amplitude-versus-offset inversion techniques were used to determine mantle temperature and composition, showing a mechanically mixed transition zone with basalt enrichment beneath the Amazon basin. This study provides direct evidence for thermochemical anomalies in the mantle and their interactions with subducting slabs.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Jihye Oh, Insung Lee, Finlay M. Stuart, Munjae Park, Jonguk Kim
Summary: The research reveals the process of mantle enrichment in the mature back-arc spreading axis in the North Fiji Basin, with enriched basalts influenced by contributions from the mantle transition zone and dehydrated oceanic slab components.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Wen-Yi Zhou, Jin S. Zhang, Quancheng Huang, Xiaojing Lai, Bin Chen, Przemyslaw Dera, Brandon Schmandt
Summary: The 520 km and 660 km discontinuities in the Earth's mantle are primarily caused by phase transitions in minerals. Global seismic studies have shown regional variations in the 520 km discontinuity, likely due to heterogeneities in the mantle. However, the effects of chemical composition and temperature on the detectability of the 520 km discontinuity are still unclear. It is also unknown whether metastable ringwoodite in subducting slabs can create a detectable seismic signature. This study provides new insights into these issues.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Timothy Chapman, Geoffrey L. Clarke
Summary: Cold subducted oceanic lithosphere may stall in the uppermost portions of the lower mantle due to slow thermal equilibration and reactions forming ferropericlase and bridgmanite. Evaluations of slab buoyancy often neglect dynamic P-T paths and the temperature-dependent expansion or contraction of stalled slabs. Slab residence at the base of the mantle transition zone is predicted to last around 150-160 Myr, with slab components potentially separating after distinct periods of heating and phase transformations.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(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)