Article
Geosciences, Multidisciplinary
Ben-Xun Su, Qi-Qi Pan, Yan Xiao, Jie-Jun Jing, Paul T. Robinson, Ibrahim Uysal, Xia Liu, Jian-Guo Liu
Summary: The traditional interpretation of mantle peridotites in ophiolites needs to be reconsidered as recent petrological and geochemical data suggest significant compositional variations and modifications in these rocks. The presence of interstitial spinel grains and widespread clinopyroxene suggests post-crystallization modifications. Amphibole and enriched Mg and Ca melts/fluids serve as evidence of the past presence of hydrous melts and indicate interactions between different lithologies. The mantle peridotites of ophiolites cannot be considered as paleo-oceanic lithospheric mantle and cannot be used for reconstructing ancient oceans or constraining global tectonic processes.
EARTH-SCIENCE REVIEWS
(2023)
Article
Geochemistry & Geophysics
Kuan-Yu Lin, Jessica M. Warren, Fred A. Davis
Summary: Trace element concentrations in abyssal peridotite olivine provide insights into the formation and evolution of the oceanic lithosphere. By studying the compositions of olivine trace elements, we investigated partial melting, melt-rock interaction, and cooling processes in mid-ocean ridges and forearc regions. We analyzed 44 peridotite samples from different spreading ridges and the Tonga trench, including samples with melt veins. Our findings show that certain elements, such as Ti, Mn, Co, and Zn, are useful tracers of melt infiltration. Additionally, the abundances of Al, Ca, Cr, and V in olivine are temperature sensitive, providing information about the cooling rates and tectonic environments. The olivine Y and Yb abundances reflect both melting and subsolidus cooling processes. Overall, olivine trace elements are valuable tools for studying seafloor spreading and mid-ocean ridge tectonics.
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
(2023)
Article
Geochemistry & Geophysics
Adina E. Pusok, Richard F. Katz, Dave A. May, Yuan Li
Summary: Geophysical observations at mid-ocean ridges show asymmetry in indicators of magma production and non-monotonic variations in lithosphere-asthenosphere boundary depth. Models incorporating melting-induced buoyancy effects can explain these observations.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Multidisciplinary Sciences
Veronique Le Roux, Benjamin M. Urann, Daniele Brunelli, Enrico Bonatti, Anna Cipriani, Sylvie Demouchy, Brian D. Monteleone
Summary: The study reveals that the H2O contents in pyroxenes from abyssal peridotites increase with crustal ages and pyroxene chemistry, contrary to common trends observed in mantle xenoliths. Post-melting hydrogen enrichment occurs through ionic diffusion during cryptic metasomatism of peridotite residues by low-degree, volatile-rich melts.
Article
Geochemistry & Geophysics
Cin-Ty Lee, Emily J. Chin
Summary: The formation of cratons during the mid-Archean to mid-Proterozoic period was favored, resulting in stable crustal shields with thick and cold mantle roots. These cratons have remained stable over time due to the high viscosity of the cratonic mantle, possibly influenced by dehydration during the formation process. Grain size may play a more significant role in controlling cratonic strength than the hydrogen content. The cratonic mantle, despite being wet and metasomatized, has achieved strength through the coarsening of grains and the passage of fluids.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
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
Sierra N. Patterson, Kendra J. Lynn, Cecile Prigent, Jessica M. Warren
Summary: Alteration mineral assemblages in abyssal peridotites from the Gakkel Ridge were analyzed, revealing a range of alteration from essentially unaltered to completely serpentinized, with a moderate to highly altered average score. The extent of alteration was found to be independent of peridotite lithology and region. Serpentine was present in all samples, with carbonate veins in 27% of samples. The abundance of tremolite, chlorite, and talc was lower than in talctremolite-chlorite schists from other regions.
Article
Multidisciplinary Sciences
Chuan-Zhou Liu, Henry J. B. Dick, Ross N. Mitchell, Wu Wei, Zhen-Yu Zhang, Albrecht W. Hofmann, Jian-Feng Yang, Yang Li
Summary: This study reveals the preservation of ancient mantle lithosphere information in abyssal peridotites and unexpected connection between young oceanic and ancient continental lithosphere, indicating a significant compositional recycling process.
Article
Geochemistry & Geophysics
A. Benard, O. Muentener, S. Pilet, R. J. Arculus, O. Nebel
Summary: Recent studies on peridotite xenoliths from mantle lithosphere beneath active arcs in Kamchatka and West Bismarck show they are enriched in silica and depleted in incompatible elements, likely due to partial melting processes in the SSZ mantle asthenosphere. The peridotites from TUBAF seamount in New Ireland also exhibit residual SSZ signatures, indicating their last melting event occurred in the mantle wedge. This suggests a shallow mantle decompression fore-arc environment during Oligocene to Miocene subduction along the Manus-Kilinailau trench.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geochemistry & Geophysics
C. Peirce, M. J. Funnell, T. J. Reston, C. J. MacLeod
Summary: This study models the structure of multiple OCCs on the Mid-Atlantic Ridge using seismic tomography. The results suggest that the formation of OCCs may be influenced by the presence of magma and the characteristics of the crust. The study also investigates the drivers of hydrothermal circulation in different vent fields, revealing varying mechanisms in different regions.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geology
J. M. Kendall, D. Schlaphorst, C. A. Rychert, N. Harmon, M. Agius, S. Tharimena
Summary: Parallel melt accumulation along the Mid-Atlantic Ridge was found, and this may enhance the driving forces of the plates.
Article
Geochemistry & Geophysics
Dante Canil, James K. Russell, Dominic Fode
Summary: The study reveals that the mantle lithosphere beneath the Canadian Cordillera is ancient and has maintained a thin and hot state for at least the past 30 million years, rather than recently cooled from the asthenosphere. Various temperature measurements indicate that the cooling rate of these mantle xenoliths is very slow.
Article
Geochemistry & Geophysics
I Nishio, K. Itano, P. Waterton, A. Tamura, K. Szilas, T. Morishita
Summary: In this study, a large database of abyssal peridotite clinopyroxene compositions was analyzed using log-ratio transformation, principal component analysis (PCA), and k-means clustering. The results showed that the variation in clinopyroxene compositions can be largely explained by two dimensions. Cluster analysis classified the compositions into four clusters, with each cluster representing different processes and degrees of partial melting and melt-rock interaction. The presence of garnet-field melting before spinel-field melting and the retained melt fraction during partial melting also influenced the compositions. This study highlights the compositional heterogeneity in abyssal peridotites.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Article
Geosciences, Multidisciplinary
Zhikai Wang, Satish C. Singh, Cecile Prigent, Emma P. M. Gregory, Milena Marjanovic
Summary: Transform faults accommodate lateral motions between lithospheric plates, and this study presents new findings about the deep structure of the Romanche transform fault. The seismic data indicates the presence of a low-velocity anomaly, likely due to extensive serpentinization and a hydrated shear mylonite zone. Water sourced from seawater-derived fluids infiltrates the fault, leading to a low-temperature, water-induced melting zone and thinning of the lithosphere at the transform fault.
Article
Geosciences, Multidisciplinary
Yinuo Zhang, Fan Zhang, Xubo Zhang, Tao Zhang, Jian Lin, Zhiyuan Zhou, Jiangyang Zhang
Summary: The mantle plumes modify geophysical and geochemical features along mid-ocean ridges. This study focuses on the interaction between the Jan Mayen Hotspot and the Mohns Ridge in the Arctic Ocean. By analyzing geophysical observations and using modeling results, the properties of the Jan Mayen plume were estimated, and the influence of the transform fault on plume dispersion was evaluated.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geochemistry & Geophysics
V Basch, A. Sanfilippo, L. Vigliotti, A. Langone, N. Rasul, M. Khorsheed, S. Al Nomani, A. Al Qutub, M. Ligi
Summary: The study of the Red Sea rift system is important for understanding the transition from a continental to an oceanic rift. By analyzing the petrology and geochemistry of rocks from the Arabian-Nubian Shield region in the southern Red Sea rift system, the researchers found evidence of early syn-rift magmatism and its influence on the geodynamic evolution of the region. The results suggest that this early magmatism led to the replacement of continental crust by oceanic gabbroic bodies, which in turn prolonged the rifting stage.
JOURNAL OF PETROLOGY
(2022)
Article
Geochemistry & Geophysics
S. G. Skolotnev, K. O. Dobrolyubova, A. A. Peyve, S. Yu Sokolov, N. P. Chamov, M. Ligi
Summary: The paper presents new data on the Doldrums megatransform fault in the northern Equatorial Atlantic, identifying several types of spreading segments with different structures based on the depth of the axial spreading zone. The shallowest spreading segments exhibit small neovolcanic rises and abyssal hills in combination with oceanic core complexes, while the deepest intra-transform spreading center shows a nonstationary position and origination of new spreading centers. Intermediate segments between the Vernadsky, Pushcharovsky, and Bogdanov Fracture zones are characterized by large neovolcanic rises in the axial zone and asymmetrical structure of the flanks.
Article
Chemistry, Inorganic & Nuclear
Thomas Ferreira da Costa Campos, Jose Humberto Araujo, Humberto Araujo, Susanna Eleonora Sichel, Valeria Fonseca da Silva Pastura, Kenji Freire Motoki, Leonardo Mairink Bara, Marcia Maia, Estefan Monteiro da Fonseca, Julio Navoni, Thais Vargas, Peter Szatmari, Daniele Brunelli
Summary: This study provides the first mapping of radiogenic heat production and radiogenic heat flow in the Saint Peter and Saint Paul Archipelago (SPSPA) in the Equatorial Atlantic Ocean. The results show that the radiogenic heat production in SPSPA is higher than predicted, while the surface radiogenic heat flow is lower, indicating a low contribution of the upper mantle to the heat flow in the region.
APPLIED RADIATION AND ISOTOPES
(2023)
Article
Geology
Luca Gasperini, Marco Ligi, Daniela Accettella, Alessandro Bosman, Marco Cuffaro, Emanuele Lodolo, Eleonora Martorelli, Filippo Muccini, Camilla Palmiotto, Alina Polonia
Summary: The study reveals that the Pacific, Antarctic, and Macquarie lithospheric plates separate from the Macquarie Triple Junction in the southwestern Pacific Ocean. Through the use of morphobathymetry, magnetic, and gravity data, the evolution of the three accretionary/transform boundaries at the MTJ has been understood. Plate velocities near the MTJ indicate an unstable ridge-fault-fault triple junction. The recent evolution of the MTJ is attributed to changes in plate motion, such as shortening of the Southeast Indian Ridge segment and the formation and lengthening of the Pacific-Antarctic Ridge.
Article
Geosciences, Multidisciplinary
Moamen Ali, Alessandro Decarlis, Marco Ligi, Philip Ball, William Bosworth, Andrea Ceriani
Summary: This paper describes the rift architecture, dynamics and evolution of the northern Red Sea and identifies domains that relate to first-order geodynamic processes. The proximal margin domain is characterized by latest Oligocene-Miocene half-graben basins, while the offshore region is a necking domain dominated by extensional faults. The distal margin domain experiences crustal thinning via a detachment fault.
JOURNAL OF THE GEOLOGICAL SOCIETY
(2023)
Article
Oceanography
D. I. Frey, V. A. Krechik, L. D. Bashirova, S. A. Ostroumova, D. A. Smirnova, L. A. Kuleshova, E. P. Ponomarenko, E. G. Morozov, M. Ligi, I. Yu. Dudkov, V. V. Sivkov
Summary: Strong acceleration of abyssal flows in narrow deep-water channels and fracture zones is a key feature of bottom circulation in the Atlantic Ocean. The main pathway for Antarctic waters in the Equatorial Atlantic is the Romanche Fracture Zone, and our survey provided the first observational evidence of intense flow into the Vema Deep. The flow splits into branches at the sill, with the northern channel being the main pathway for the coldest and densest bottom waters to the Vema Deep. We estimated the total transport of Antarctic Bottom Water through the Romanche Fracture Zone at this location to be 1.40 Sv, with velocities exceeding 10 cm/s at depths greater than 5,000 m.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Geochemistry & Geophysics
Clement Vincent, Marcia Maia, Anne Briais, Daniele Brunelli, Marco Ligi, Susanna Sichel
Summary: Accretionary processes at mid-ocean ridge segments with low magma input have seldom been investigated over the long term. The evolution of such magma-starved segments over time is still largely unknown. On the flanks of the axial ridge segment, we observe a succession of structures exhumed by detachment faulting, evolving from east-facing, long-lived, corrugated oceanic core complexes (similar to 6 Ma ago), to short-lived detachment faults exposing lower crust and mantle rocks and facing alternatively east and west in the more recent part of the segment. The westward relocations of the plate boundary appear to compensate for the asymmetry of accretion through detachment faulting, overall creating the same amount of lithosphere on both flanks of the ridge. We interpret the observed changes in the time of the accretionary processes to reflect a decrease of the melt supply over the last similar to 6 Myr.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2023)
Article
Geochemistry & Geophysics
M. Bickert, M. Cannat, D. Brunelli
Summary: At the Eastern part of the Southwest Indian Ridge (SWIR), large offset normal faults called detachment faults exhume mantle-derived rocks on the seafloor, with some samples showing evidence of hydration. The presence of syn-kinematic amphibole in microshear zones at the root zone of the detachment suggests a hydrothermal origin, indicating that seawater-derived fluids percolated down to this region. However, the constant exhumation of new mantle material and the limited lifetime of each detachment prevent a more widespread deep hydration compared to transform fault plate boundaries.
Article
Geochemistry & Geophysics
Anna Cipriani, Tommaso Giovanardi, Maurizio Mazzucchelli, Federico Lugli, Marie C. Sforna, Alessandro F. Gualtieri, Dario Di Giuseppe, Mario Gaeta, Daniele Brunelli
Summary: This study presents chemical and mineralogical data on a carbonate-bearing fluorapatite megacryst from the Veneto Volcanic Province in Italy. The data suggests that the crystallization of the fluorapatite occurred at a depth from a nelsonitic or evolved alkaline melt source metasomatized by carbonate-rich fluids. The presence of Cronstedtite and other minerals indicates low temperature hydrothermal alteration of the volcanics in the area.
MINERALOGY AND PETROLOGY
(2023)
Article
Geochemistry & Geophysics
S. G. Skolotnev, K. O. Dobrolyubova, A. A. Peyve, S. Yu. Sokolov, N. P. Chamov, M. Ligi
Summary: This study presents the structural and morphological analysis of fracture zones in the Doldrums Megatransform System (DMS) in the northern part of the Equatorial Atlantic. The width and depth variations of fracture zone valleys are influenced by stress distribution and upper mantle temperature. The research reveals the processes and mechanisms of landform formation through the analysis of different fracture zones.
Article
Geosciences, Multidisciplinary
Moamen Ali, Hemin Koyi, William Bosworth, Marco Ligi, Philip J. Ball, Alessandro Decarlis
Summary: This study systematically investigates the distribution and morphology of salt structures in the northern Egyptian Red Sea using seismic surveys and well data. The results indicate that the salt layer developed into five major salt walls, with symmetrical and asymmetrical folds and two categories of normal faults also present. The salt mobilization started in the Late Miocene and continues to the present day.
JOURNAL OF STRUCTURAL GEOLOGY
(2023)
Article
Multidisciplinary Sciences
Melania Gigante, Alessandro Mazzariol, Jacopo Bonetto, Elena Armaroli, Anna Cipriani, Federico Lugli
Summary: Since prehistoric times, Sardinia has played an important role in human population and mobility, as well as the circulation of raw materials, languages, and culture. This study fills a gap in the research of geographical provenance in ancient skeletal populations of Sardinia by developing the first isoscape of southern Sardinia using bioavailable Sr isotope data and a machine-learning approach. The study successfully determines the geographic origin and mobility of archaeological and modern fauna in the Nora and Pula Plain areas using a Bayesian provenance assignment workflow.
Article
Multidisciplinary Sciences
Manon Bickert, Mary-Alix Kaczmarek, Daniele Brunelli, Marcia Maia, Thomas F. C. Campos, Susanna E. Sichel
Summary: Deformed mantle rocks exposed by oceanic transform faults reveal that fluid-assisted ductile deformation occurs at high temperatures and pressures, which plays a crucial role in controlling deep faulting at plate boundaries.
NATURE COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Dmitrii G. Borisov, Dmitry I. Frey, Elena V. Ivanova, Nikolay N. Dmitrevskiy, Oleg V. Levchenko, Vladimir V. Fomin, Marco Ligi
Summary: This study describes the first identified example of a contourite depositional system in the Vema Fracture Zone, emphasizing the importance of further research on contourites in this area and the need to reevaluate the impact of bottom currents on sedimentation, particularly in narrow valley segments of the fracture zone.
SCIENTIFIC REPORTS
(2023)
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)