Article
Engineering, Marine
Tianxiao Ji, Zhigang Zeng
Summary: This paper presents new data on the major elements, trace elements, and Nd-Hf isotopes of south mid-Atlantic ridge (SMAR) MORBs. The geochemical characteristics, including enrichment of fluid-mobile elements and anomalous trace element ratios, suggest that these MORBs have been modified by subduction.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Geochemistry & Geophysics
Fei Wu, Simon Turner, Kaj Hoernle, Folkmar Hauff, Bruce F. Schaefer, Thomas Kokfelt, Ilya Bindeman
Summary: Stable barium (Ba) isotopes are being used as tracers for the recycling of crustal material into the mantle. Small but significant Ba isotope variations have been found in global MORB, and this study provides new constraints on the Ba isotope composition of the depleted upper mantle and the origin of Ba isotope heterogeneity in MORB. The results indicate that recycled altered oceanic crust and crustal sedimentary materials play important roles in the chemical budget of the upper mantle.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geochemistry & Geophysics
Pengyuan Guo, Yaoling Niu, Pu Sun, Junjie Zhang, Shuo Chen, Meng Duan, Hongmei Gong, Xiaohong Wang
Summary: The study provides new Sr-Nd-Hf isotopic data on mid-ocean ridge basalts from the Oceanographer and Hayes fracture zones at the Mid-Atlantic Ridge to constrain the nature and origin of upper mantle heterogeneity. The data illustrate that the mantle sources of these lavas comprise three components, including ADM, E-type I, and E-type II components, which explain the contrast in crustal thickness, ridge morphology, and mantle Bouguer anomalies between the two ridge segments.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geochemistry & Geophysics
Shuo Chen, Pu Sun, Yaoling Niu, Pengyuan Guo, Tim Elliott, Remco C. Hin
Summary: The study reveals significant variations in molybdenum isotopes in mid-ocean ridge basalts, indicating mantle compositional heterogeneity. The variations in Mo isotope compositions are best explained by two-component mixing between incompatible element depleted and enriched endmembers. The findings suggest that recycled oceanic mantle lithosphere metasomatized by low degree melt plays a key role in the formation of source lithologies in the East Pacific Rise.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Z. T. Eriksen, S. B. Jacobsen
Summary: Lithological and isotopic heterogeneity in the mantle provide valuable insights into the mantle's melting history and crustal recycling processes. Oceanic basalts, specifically OIBs and MORBs, are important tools for studying mantle heterogeneity. In this study, the systematics of stable calcium isotopes in OIBs and MORBs were explored to probe mantle heterogeneity.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Attreyee Ghosh, Debanjan Pal
Summary: The Indian Ocean geoid low (IOGL) is one of the lowest geoid anomalies on Earth. Several theories have been proposed to explain its formation, including past subduction, subduction coupled with low velocity anomalies in the upper mantle, and hot, low density anomaly in the upper to mid mantle depths. This study investigates the contribution of lower mantle slabs to the IOGL and confirms their minimal role.
Article
Geochemistry & Geophysics
Alessio Sanfilippo, Vincent J. M. Salters, Sergey Y. Sokolov, Alexander A. Peyve, Andreas Stracke
Summary: The upper mantle is a mixture of refractory and recycled crustal domains, with the recycled portions dominating the composition of surface basalts. Hf isotope ratios may provide hints for melting of refractory source materials in basalts, allowing the identification of depleted mantle materials. Basalts from the Arctic Atlantic show high Hf isotope ratios, suggesting a highly depleted asthenospheric mantle source beneath this region.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geochemistry & Geophysics
Soumen Mallick, Sophie E. Kuhl, Alberto E. Saal, Emily M. Klein, Wolfgang Bach, Brian D. Monteleone, Joseph S. Boesenberg
Summary: Several geochemical studies have confirmed the presence of compositional and lithological heterogeneities in mid-ocean ridge basalts. While the composition and age of these heterogeneities have been constrained, their origin remains highly debated.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
Brian E. Tucholke, Ross Parnell-Turner, Deborah K. Smith
Summary: Magma supply plays a primary role in controlling seafloor morphology of oceanic crust. The study examines the global patterns of morphology on mid-ocean ridge flanks in relation to magma supply and spreading rate. The results demonstrate that morphology becomes more isotropic and irregular with decreasing magma supply. The study also reveals that seismically determined crustal thickness in certain regions includes significant non-magmatic components. The findings have implications for understanding the evolution of oceanic crust.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geology
Nicholas D. Barber, Marie Edmonds, Frances Jenner, Helen Williams
Summary: The transfer of material from subducting slabs to the overlying mantle is an important process in Earth's geochemical cycles. By analyzing global arc magma compositions, researchers have found peaks in the Ba/Nb ratio that can be linked to the progressive breakdown of hydrous minerals in subducting slabs.
Article
Geochemistry & Geophysics
Luise J. Wagner, Ilka C. Kleinhanns, Maria I. Varas-Reus, Carolina Rosca, Stephan Konig, Wolfgang Bach, Ronny Schoenberg
Summary: Stable isotopes of chromium and iron are useful indicators of redox conditions in magmatic systems. Partial melting and fractional crystallization are dominant fractionation processes for these isotopes, but the source mineralogy also plays a significant role. This study analyzes MORB glasses to investigate the role of magmatic processes and source isotope signatures on the composition of chromium and iron isotopes.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geochemistry & Geophysics
S. Brown Krein, Z. J. Molitor, T. L. Grove
Summary: The study presents a new algorithm, RevPet, to infer mantle melting conditions based on evolved basalts that have experienced multiphase fractional crystallization. Results show that the average apparent mantle potential temperature of basaltic glasses is around 1322 degrees C with melting pressures of 13 kbars. Variations in ambient MOR T-P are observed, with the estimate that it is generally homogeneous around 1350-1400 degrees C, except near hotspots where T-P can reach approximately 1600 degrees C.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Hiroshi Sato, Shiki Machida, Kana Ashida, Ryoko Senda, Kentaro Nakamura, Shigekazu Yoneda
Summary: Numerous studies have shown that the mid-ocean-ridge basalts (MORBs) in the southern Central Indian Ridge (CIR) exhibit the DUPAL anomaly. The results indicate that the MORB from the spreading axis is produced by a mixture of depleted MORB mantle and melt from the lower continental crust (LCC), while the off-axis MORB shows a depleted trace element composition due to the mixture of a highly depleted mantle and melt from LCC and C component. The off-axis area of the CIR-1 segment has undergone at least two melting events, including the formation of the current MORB.
Article
Multidisciplinary Sciences
Xiyuan Bao, Carolina R. Lithgow-Bertelloni, Matthew G. Jackson, Barbara Romanowicz
Summary: Research suggests that volcanic hotspots vary greatly in temperature, with some being extremely hot, some cold, and others not hot enough to actively upwell. Cold hotspots may originate from the upper mantle depth or be cooled by small-scale convection.
Review
Geology
Yang Zhen, Wang GuiQin, Xu YuMing, Zeng YuLing
Summary: The challenge of studying the Earth's core-mantle interaction is that samples at the boundary between the core and mantle cannot be obtained using current technology. Ocean island basalts and flood basalts are considered to be the best samples for researching this interaction. W-182 isotope has unique geochemical properties and is an important tool for studying the Earth's core-mantle interaction. However, the mechanism of W isotope exchange between the core and mantle is still controversial.
ACTA PETROLOGICA SINICA
(2022)
Article
Multidisciplinary Sciences
Weidong Sun, Charles H. Langmuir, Neil M. Ribe, Lipeng Zhang, Saijun Sun, He Li, Congying Li, Weiming Fan, Paul J. Tackley, Patrick Sanan
Summary: The study highlights the inconsistency between the volcanic migration rates of the Emperor seamounts and the drifting rate of the Pacific plate, indicating significant northward and southward absolute movements of the seamounts. Numerical modeling suggests that this may be due to the attraction and capture of the upper part of the plume by a moving spreading ridge.
Article
Astronomy & Astrophysics
Ravit Helled, Stephanie Werner, Caroline Dorn, Tristan Guillot, Masahiro Ikoma, Yuichi Ito, Mihkel Kama, Tim Lichtenberg, Yamila Miguel, Oliver Shorttle, Paul J. Tackley, Diana Valencia, Allona Vazan
Summary: The Ariel ESA mission aims to measure the atmospheric composition of exoplanets to better understand their bulk compositions. This will advance exoplanet characterisation and provide new insights into the nature of planets in our galaxy.
EXPERIMENTAL ASTRONOMY
(2022)
Article
Geochemistry & Geophysics
J. M. Guerrero, J. P. Lowman, P. J. Tackley
Summary: The high thermal diffusivity of Mercury's mantle compared to other rocky bodies is due to iron depletion. This affects the planet's thermal history models. Analyzing heat flow and boundary ratios helps understand the current conductive cooling of Mercury's mantle and its implications on core heat loss.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geochemistry & Geophysics
S. M. Langemeyer, J. P. Lowman, P. J. Tackley
Summary: More than two decades of research have made progress in generating plate-like surface behavior in models of mantle convection. The properties required for dynamic plates from mantle convection have been widely recognized and used in both 2-D and 3-D geometries. Studying the properties needed to obtain deep mantle features with LLSVP-like characteristics has become a topic of interest. The study focuses on discovering the properties that can produce a detached pair of 3-D features different from the ambient mantle.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geosciences, Multidisciplinary
Yang Li, Frederic Deschamps, Zhidong Shi, Joshua M. Guerrero, Wen-Pin Hsieh, Liang Zhao, Paul J. Tackley
Summary: The composition-dependent thermal conductivity of primordial dense material has a secondary role in the long-term evolution of Earth's mantle, but if the material is enriched in heat-producing elements, it slightly affects the height and coverage of these reservoirs.
EARTH PLANETS AND SPACE
(2022)
Article
Geosciences, Multidisciplinary
Xavier Borgeat, Paul J. Tackley
Summary: Research has shown that impacts can have a significant impact on early Earth's tectonics and mantle mixing, including triggering subduction and increasing compositional heterogeneity in the mantle. In cases of stagnant-lid tectonics, impacts can shift the behavior to plate-like regimes, but this change is temporary.
PROGRESS IN EARTH AND PLANETARY SCIENCE
(2022)
Article
Geochemistry & Geophysics
A. J. P. Guelcher, G. J. Golabek, M. Thielmann, M. D. Ballmer, P. J. Tackley
Summary: The rheological properties of Earth's lower mantle play a crucial role in mantle dynamics and planetary evolution. This study presents a new strain-dependent rheology formulation for lower mantle materials, which has several direct and indirect effects on mantle convection. The results suggest that the new rheology formulation leads to changing dynamics of weakened plume channels, formation of larger thermochemical piles, and increased convective vigor. Furthermore, it may explain the discrepancy between expected and observed thermal anomalies of deep-seated mantle plumes on Earth.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Article
Geochemistry & Geophysics
A. C. Adams, D. R. Stegman, S. E. Smrekar, P. J. Tackley
Summary: Our understanding of the tectonic framework governing Venus is limited, but there may be regional-scale resurfacing phenomena, with rift zones potentially triggering decoupling between the crust and lithospheric mantle. Numerical modeling suggests that negative buoyancy in the lithospheric mantle could lead to plate delamination, impacting Venus's volcanic activity and tectonic deformation.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2022)
Article
Astronomy & Astrophysics
Laetitia Lebec, Stephane Labrosse, Adrien Morison, Paul J. Tackley
Summary: The presence of a high-pressure ice layer between the silicate core and the liquid ocean in large icy moons and ocean worlds has been considered as a hindrance to habitability. However, recent studies have challenged this view and demonstrated the possibility of nutrient transfer under specific conditions. Our study takes into account the dynamical implications of the phase equilibrium at the ice-ocean interface, which allows exchanges between the high-pressure ice layer and the liquid ocean. We propose a scaling relationship between the bottom temperature, top vertical velocity, and Rayleigh number, considering different values of a dimensionless parameter phi.
Article
Astronomy & Astrophysics
Harry A. Ballantyne, Martin Jutzi, Gregor J. Golabek, Lokesh Mishra, Kar Wai Cheng, Antoine B. Rozel, Paul J. Tackley
Summary: A giant impact is suggested as the explanation for the Martian Dichotomy, with recent studies favoring a hybrid origin caused by impact-induced crust-production. This study uses a large suite of impact simulations and a sophisticated geophysical scheme to investigate the feasibility of a giant impact on either hemisphere of Mars. The results suggest that a cannonical Borealis-forming impact is not possible, but instead favor an impact and subsequent localised magma ocean in the southern hemisphere that results in a thicker crust than the north.
Article
Geochemistry & Geophysics
Joshua Martin Guerrero, Frederic Deschamps, Yang Li, Wen-Pin Hsieh, Paul James Tackley
Summary: The effect of heterogeneous thermal conductivity on the stability of primordial material reservoirs in the mantle is examined using 2D spherical annulus geometry simulations. The depth-dependent profiles of mantle conductivity in numerical models often mask the effects of temperature and composition dependencies. By considering these dependencies and the reduction in thermochemical pile conductivity, it is found that a depth-dependent ratio of at least 9 is needed for stable primordial reservoirs. When the lowermost mantle's mean conductivity is greater than twice the surface conductivity, reservoirs can remain stable for very long periods of time.
Article
Geochemistry & Geophysics
Anna Johanna Pia Guelcher, Maxim Dionys Ballmer, Paul James Tackley
Summary: By using global-scale 2D models of thermochemical mantle convection, the study investigates the evolution and mixing of recycled and primordial heterogeneity in Earth's lower mantle. The models predict various regimes of mantle evolution and heterogeneity preservation over 4.5 Gyr based on physical parameters. Results show that primordial and recycled heterogeneity can co-exist in the lower mantle of Earthlike planets.
Article
Environmental Sciences
Sean M. Langemeyer, Julian P. Lowman, Paul J. Tackley
Summary: This study suggests that mantle convection can lead to the movement of lithosphere, resulting in dynamically derived plate boundaries with contrasting superficial structure that can distinguish between convergence and divergence.
COMMUNICATIONS EARTH & ENVIRONMENT
(2021)
Article
Geochemistry & Geophysics
Daniela Paz Bolrao, Maxim D. Ballmer, Adrien Morison, Antoine B. Rozel, Patrick Sanan, Stephane Labrosse, Paul J. Tackley
Summary: Terrestrial planets undergo magma ocean episodes after formation, leading to the formation of a solid rocky mantle through crystallisation. Chemical fractionation due to fractional crystallisation continuously changes the composition of the solid mantle and liquid reservoirs. Convection in the solid mantle is dominated by large wavelengths, and material transfer across boundaries promotes chemical equilibrium.
Article
Astronomy & Astrophysics
Tobias G. Meier, Dan J. Bower, Tim Lichtenberg, Paul J. Tackley, Brice-Olivier Demory
Summary: The study utilizes observations from the thermal phase curve of LHS 3844b to analyze the planet's interior dynamics and tectonic regimes through numerical models. Three viable convective regimes are identified, with the observation of hemispheric tectonics in certain scenarios.
ASTROPHYSICAL JOURNAL LETTERS
(2021)