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
Hongda Hao, Ian H. Campbell, Richard J. Arculus, Michael R. Perfit
Summary: The study reveals that most primitive mid-ocean ridge basalts have low platinum-group element content, which may be due to changes in sulfur saturation during ascent from the mantle to the ridge magma chamber. Sulfide saturation status can be determined by changes in Pd content, and frequent small replenishments in the magma chamber help maintain sulfide saturation status.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
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
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
Geology
Emma P. M. Gregory, Satish C. Singh, Milena Marjanovic, Zhikai Wang
Summary: Using seismic data, researchers have found the presence of a Moho and a low-velocity anomaly beneath the Romanche transform valley floor, suggesting the crust may consist of fractured mafic material. The complex and heterogeneous structure of the transform fault could have significant influence on earthquake rupture and alteration processes.
Article
Mechanics
Joyjeet Sen, Shamik Sarkar, Nibir Mandal
Summary: This article explores the interaction dynamics between the elastic oceanic crust and the underlying mush complexes (MC) to understand the axial topography of mid-ocean ridges (MORs). The effective viscosity (mu(eff)) of MC is identified as the key factor in determining the high or flat topography of MORs. By calculating the viscosity based on melt suspension characteristics and volume fraction in the MC region, a numerical model confirms that the axial topography of model MORs is influenced by mu(eff). The findings are validated with observations from natural MORs.
Article
Geochemistry & Geophysics
Chuanshun Li, Haitao Zhang, Yili Guan, Aimei Zhu, Xuefa Shi
Summary: This study presents new major and trace element as well as Sr-Nd-Pb isotope data for basalts from the South Mid-Atlantic Ridge. The results indicate the presence of Tristan mantle plume materials in the southern SMAR asthenosphere, which has influenced the geochemical compositions of the basalts in this region.
Article
Geochemistry & Geophysics
Haitao Zhang, Quanshu Yan, Chuanshun Li, Xuefa Shi, Yaomin Yang, Guozhi Wang, Qingfeng Hua, Zhiwei Zhu, Hui Zhang, Renjie Zhao
Summary: The study reveals that basalts from the South Mid-Atlantic Ridge contain chemical traces of the Saint Helena hotspot, with its influence extending from approximately 14.2 degrees S to 20.8 degrees S. Material flow from Cardno seamount toward the SMAR system may account for the stronger geochemical signals observed in certain segments along the ridge axes.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
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
Geosciences, Multidisciplinary
S. Cesca, M. Metz, P. Bueyuekakpinar, T. Dahm
Summary: A series of seismic activities occurred in the northern section of the Mid-Atlantic Ridge (latitude 53.3°-54.3°) from 26 September to 10 December 2022. Through the analysis of regional, teleseismic, and array data, we were able to locate 61 hypocenters and determine 77 moment tensors. The cumulative moment released during the 2022 swarm is equivalent to Mw 6.3. The majority of earthquakes were shallow with a depth of 7±3 km, and they mainly occurred along the ridge axis with normal faulting mechanisms. However, some of the larger and more recent earthquakes exhibited unusual thrust mechanisms and occurred as far as 25 km from the ridge. This swarm is believed to be caused by a shallow magmatic intrusion, starting with a vertical dike propagating approximately 60 km along the ridge axis, followed by shallow normal faulting and eventually triggering thrust earthquakes off the ridge due to the buildup of compressive stress. This unrest provides a rare example of a highly energetic, magmatic-driven swarm episode at a mid-ocean ridge.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Jonathan M. Tucker, Peter E. van Keken, Chris J. Ballentine
Summary: Oceanic crust subduction stores a significant amount of argon in the Earth's mantle, while the missing argon-40 from the atmosphere can be explained by high concentrations of argon-40 associated with potassium-rich subducted oceanic crust and unmelted material dispersed throughout the mantle.
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
Geosciences, Multidisciplinary
Tran Danh Hung, Ting Yang, Ba Manh Le, Youqiang Yu, Mei Xue, Baohua Liu, Chenguang Liu, Jian Wang, Mohan Pan, Phan Thien Huong, Fang Liu, Jason P. Morgan
Summary: The study of crustal thickness and Vp/Vs ratios near an extinct mid-ocean ridge in the South China Sea reveals that as spreading ceased, the oceanic crust abruptly thinned and shifted to an ultraslow accretion style. Abnormally high Vp/Vs ratios indicate the presence of serpentine, suggesting the formation of normal faults and the enhancement of serpentinization along the ridge axis.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Review
Environmental Sciences
Gretchen L. Frueh-Green, Deborah S. Kelley, Marvin D. Lilley, Mathilde Cannat, Valerie Chavagnac, John A. Baross
Summary: Hydrothermal circulation and alteration at mid-ocean ridges play a crucial role in regulating seawater chemistry and global chemical fluxes. Different spreading rates of mid-ocean ridges result in variations in hydrothermal systems, with magmatic-dominated systems at high temperatures and alkaline fluids, and serpentinizing systems at lower temperatures. Magmatic hydrothermal systems sustain a diverse microbial biosphere, while serpentinizing systems harbor a limited microbial community consisting of methane-metabolizing archaea.
NATURE REVIEWS EARTH & ENVIRONMENT
(2022)
Article
Geology
David A. Neave, Olivier Namur
Summary: Mid-ocean ridge and ocean-island basalts provide important but incomplete insights into mantle chemistry. Through experimental observations and analyses of natural crystals and glasses, researchers infer that high-anorthite plagioclase grows from high-degree melts of refractory but otherwise unexotic mantle sources with depleted incompatible-element compositions. The widespread occurrence of high-anorthite plagioclase in oceanic basalts and the oceanic crust indicates the significant role of refractory melts in crustal accretion.
Article
Geosciences, Multidisciplinary
Stefano Tavani, Andrea Billi, Amerigo Corradetti, Marco Mercuri, Alessandro Bosman, Marco Cuffaro, Thomas Seers, Eugenio Carminati
Summary: Major advances in smartphones and tablets have transformed them into key digital platforms for geological fieldwork. The introduction of a native LiDAR scanner on the iPhone 12 Pro has brought about a potential paradigm shift in digital geological fieldwork. The performance of the iPhone 12 Pro in terms of geo-location accuracy, orientation data collection, imaging capabilities, and LiDAR scanning has been evaluated and found to be comparable to traditional geological field tools.
EARTH-SCIENCE REVIEWS
(2022)
Article
Geochemistry & Geophysics
Neil C. Mitchell, Karina Hernandez, Jonas Preine, Marco Ligi, Nico Augustin, Ay Izzeldin, Christian Huebscher
Summary: Rayleigh-Taylor models predict that diapirs should develop with characteristic spacings, but our study on the deep-water Miocene evaporites in the Red Sea shows that the diapirism does not have a uniform scale. The topography of the S-reflection indicates stochastic behavior with a range of around 3 km. The Rayleigh-Taylor model does not explain the deformation in the Red Sea evaporites. The findings provide insights into the vertical and length scales of early-stage salt giants.
Article
Geosciences, Multidisciplinary
S. G. Skolotnev, A. A. Peyve, A. N. Ivanenko, K. O. Dobrolyubova, A. Sanfilippo, M. Ligi, S. Yu. Sokolov, I. A. Veklich, L. Petracchini, V. Basch, C. Ferrando, C. Sani, M. Bickert, F. Muccini, C. Palmiotto, M. Cuffaro, D. A. Kuleshov, V. N. Dobrolyubov, N. A. Shkittin, S. A. Dokashenko, E. S. Yakovenko
Summary: The geological structure of a large volcanic edifice in the eastern flank of the Charlie Gibbs Fracture Zone in the Eastern Thule submarine rise region (North Atlantic) is discussed. The volcanic edifice was formed near the Mid-Atlantic Ridge about 64-67 million years ago and was subsequently eroded by waves and sank into the oceanic plate at a depth of 2500 meters. The study concludes that volcanic activity in the Rockall Rift Basin also affected the region further south, which had already become an oceanic basin and was separated from the rift basin by the Charlie Gibbs Fracture Zone.
DOKLADY EARTH SCIENCES
(2022)
Article
Engineering, Geological
Luca Gasperini, Filippo Zaniboni, Alberto Armigliato, Stefano Tinti, Gianluca Pagnoni, Mehmet Sinan Ozeren, Marco Ligi, Francesca Natali, Alina Polonia
Summary: Based on morphobathymetric and seismic reflection data, this study examines a large landslide body in the eastern Sea of Marmara and its potential to cause tsunamis along the North Anatolian Fault. The results suggest that the sliding of the landslide mass could generate tsunamis exceeding 15-20 m in the eastern Sea of Marmara. The study emphasizes the need for more marine geological/geophysical data to better understand the hazards and develop emergency plans.
Article
Physics, Multidisciplinary
Marco Ligi, Marco Cuffaro, Filippo Muccini, Enrico Bonatti
Summary: Half a century ago, there was a shift in our understanding of the Earth, from a Planet with fixed continents and stable ocean basins to one with moving continents and active ocean basins. The lithosphere, the outermost rigid layer of the Earth, plays a significant role in the generation and evolution of the Earth's lithosphere beneath the oceans. This article discusses the processes of lithosphere generation at mid-ocean ridges and focuses on a specific segment of the Mid Atlantic Ridge to examine the evolution of lithosphere generation over millions of years.
RIVISTA DEL NUOVO CIMENTO
(2022)
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
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
Geology
Mimmo Palano, Andrea Billi, Alessia Conti, Marco Cuffaro, Barbara Orecchio, Debora Presti, Silvia Scolaro, Federica Sparacino, Cristina Totaro
Summary: The Calabrian Orogenic Arc is affected by active extensional and strike-slip tectonics, and there are significant differences between its western and eastern sectors. By modeling geodetic data, a causative fault has been identified that is responsible for seismic activity in the region.
ITALIAN JOURNAL OF GEOSCIENCES
(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
Geosciences, Multidisciplinary
S. G. Skolotnev, A. A. Peyve, A. Sanfilippo, A. N. Ivanenko, M. Ligi, I. A. Veklich, L. Petracchini, V. Basch, D. A. Kuleshov, C. Ferrando, V. N. Dobrolyubov, C. Sani, N. A. Shkittin, M. Bickert, S. A. Dokashenko, F. Muccini, E. S. Yakovenko, C. Palmiotto, M. Cuffaro
Summary: This paper presents geological and geophysical data collected during the 53rd cruise of the R/V Akademik Sergey Vavilov. It shows that the distribution of Icelandic plume material extends further to the south beyond the Bight transform fault. The study also determines the half-spreading rate in the area between the Bight transform fault and the Modred nontransform fault.
DOKLADY EARTH SCIENCES
(2022)
Article
Geosciences, Multidisciplinary
Camilla Palmiotto, Eleonora Ficini, Maria Filomena Loreto, Filippo Muccini, Marco Cuffaro
Summary: This study investigated the regional morphology of the Northern Lau Basin's back-arc spreading centers and compared it to the relative spreading rates. By using magnetic data, a more accurate spreading rate of 60.2 mm/year was obtained for the Northwest Lau Spreading Centers. Moreover, numerical models revealed active deformation in the mantle, explaining the anomalous magmatic production in the Northern Lau Back-Arc Basin.