Article
Geochemistry & Geophysics
Michaela Meier, Vera Schlindwein, John-Robert Scholz, Jonah Geils, Mechita C. Schmidt-Aursch, Frank Krueger, Wojciech Czuba, Tomasz Janik
Summary: Studies on ultraslow spreading ridges show distinct seismic activity variations along the axis, potentially explaining uneven magma distribution due to melt guidance towards major volcanic centers. Additionally, aseismic deformation in certain regions suggests alteration in mantle rocks, potentially indicating weakening.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Multidisciplinary Sciences
H. H. Stubseid, A. Bjerga, H. Haflidason, L. E. R. Pedersen, R. B. Pedersen
Summary: This study utilizes sediment thickness and C-14 age data to determine the age of the ocean floor in the oblique ultraslow-spreading Mohns Ridge, revealing a systematic pattern of young volcanism outside axial volcanic ridges.
NATURE COMMUNICATIONS
(2023)
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
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)
Article
Multidisciplinary Sciences
Zhikai Wang, Satish C. Singh
Summary: Using wide-angle seismic data from the equatorial Atlantic Ocean, this study shows that the crustal thickness is nearly uniform across five crustal segments formed at the slow-spreading Mid-Atlantic Ridge. The crust is predominantly of magmatic origin, likely due to a two-dimensional sheet-like mantle upwelling facilitated by long-offset transform faults and a high concentration of volatiles in the mantle.
NATURE COMMUNICATIONS
(2022)
Article
Geochemistry & Geophysics
M. Meier, V Schlindwein, F. Schmid
Summary: Along ultraslow spreading ridges, melt is distributed unequally, but melt focusing guides it towards volcanic centers. However, the detailed process of melt extraction is not yet understood.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Article
Environmental Sciences
Boris Marcaillou, Frauke Klingelhoefer, Muriel Laurencin, Jean-Frederic Lebrun, Mireille Laigle, Serge Lallemand, Laure Schenini, Aurelien Gay, Milton Boucard, Kingsley Ezenwaka, David Graindorge
Summary: Seismic and bathymetric data from the Northeastern Lesser Antilles Subduction Zone reveal a unique tectonic fabric characterized by sequences of Ridgeward-Dipping Reflectors, which may have been formed during the early stages of exhumation. Plate bending near the trench could have reactivated this fabric, enabling deep fluid circulation and serpentinization of basement rocks. Detachment faults in the oceanic basement at this subduction zone could be responsible for controlling reduced interplate seismicity through deep fluid circulation and serpentinization.
COMMUNICATIONS EARTH & ENVIRONMENT
(2021)
Article
Geochemistry & Geophysics
R. W. Allen
Summary: The formation of the Grenada back-arc Basin remains mysterious and controversial, but a new study using wide-angle seismic data suggests the presence of oblique magmatic spreading in the southern basin. This research not only contributes to understanding the tectonic history of the eastern Caribbean region, but also sheds light on the complexities of back-arc processes globally that the Lesser Antilles arc may help illuminate.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Naixiao Xu, Lingmin Zhang, Huaiyang Zhou, Hao Cheng
Summary: The study discovered mosaic zircons in different rock types at different depths in the Southwest Indian Ridge, with mantle-like characteristics. The mosaic subdomains in a single zircon are correlated with trace elements and fractures, indicating that these variations were produced during crystallization and associated with brittle deformation.
Article
Geosciences, Multidisciplinary
Antonio Gonzalez-Fernandez
Summary: The stacked refraction convolution section is an interpretation tool for wideangle refraction seismic data recorded by Ocean Bottom Seismometers. By stacking convolved forward-reverse refraction recordings, the signal to noise ratio can be improved and data interpretation can be enhanced.
FRONTIERS IN EARTH SCIENCE
(2021)
Article
Oceanography
Yunlong Liu, Vera Schlindwein, Lei Qiu, Minghui Zhao, Haijiang Zhang, Jianping Zhou, Jiazheng Zhang, Hanchuang Wang, Tao Wu, Xianming Deng
Summary: Hydrothermal processes differ between detachment settings at slow and ultraslow spreading ridges and melt-rich faster spreading ridges. Detachment faulting allows for off-axis high-temperature hydrothermal vents, while seismic data from slow spreading ridges reveal that hydrothermal fluids may exploit detachment faults to extract heat. However, knowledge of the subsurface structure and kinematic processes of detachment faults, and their interaction with hydrothermal fields at the slowest spreading ridges, is still insufficient.
DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS
(2023)
Article
Multidisciplinary Sciences
Daniel Sauter, Gianreto Manatschal, Nick Kusznir, Charles Masquelet, Philippe Werner, Marc Ulrich, Paul Bellingham, Dieter Franke, Julia Autin
Summary: The source of massive magma production at volcanic rifted margins remains disputed. Accurate estimation of extruded and intruded melt products within rifted continental crust is still lacking using geophysical methods. This study investigates the magma budget along the South Atlantic margins, revealing that most of the southernmost Atlantic Ocean opened without anomalously hot mantle and high magma supply. Alternative explanations should be favored to explain the thick magmatic layer.
SCIENTIFIC REPORTS
(2023)
Article
Geochemistry & Geophysics
Kevin Growe, Ingo Grevemeyer, Satish C. Singh, Milena Marjanovic, Emma P. M. Gregory, Cord Papenberg, Venkata Vaddineni, Laura Gomez de la Pena, Zhikai Wang
Summary: Recent studies have challenged the idea that transform zone crust may be magmatically augmented instead of anomalous hydrated lithosphere. Research on the St. Paul fracture zone revealed that the crust along and away from the fracture zone showed almost uniform thickness of 5-6 km, resembling normal oceanic crust.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Computer Science, Interdisciplinary Applications
Gabriella Alodia, Chris M. Green, Andrew M. McCaig
Summary: This study develops a novel geomorphometric technique to automate terrain classification based on the parameters of shape, directionality, and curvature of the seafloor. The application of this technique in the Mid-Atlantic Ridge yields consistent results with previous qualitative interpretations and seismic activity distribution, providing new insights into seafloor classification and the potential for automated mapping in other slow-spreading ridge regions.
COMPUTERS & GEOSCIENCES
(2022)
Article
Geochemistry & Geophysics
Qingkai Fan, Jean-Arthur Olive, Mathilde Cannat
Summary: The thermal structure of mid-ocean ridge axes has a critical impact on the mechanical properties of young lithosphere. Models combining magmatic intrusions with hydrothermal convection reveal trends of decreasing venting temperatures with increasing intrusion periodicity. Understanding the depth-extent and vigor of hydrothermal circulation in ultraslow spreading ridges remains a key challenge for future research.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Masakazu Fujii, Kyoko Okino, Taichi Sato, Hiroshi Sato, Kentaro Nakamura
EARTH AND PLANETARY SCIENCE LETTERS
(2016)
Article
Geochemistry & Geophysics
Kentaro Nakamura, Shiki Machida, Kyoko Okino, Yuka Masaki, Koichi Iijima, Katsuhiko Suzuki, Yasuhiro Kato
GEOCHEMICAL JOURNAL
(2016)
Article
Geochemistry & Geophysics
Trond Kvarven, Rolf Mjelde, Berit Oline Hjelstuen, Jan Inge Faleide, Hans Thybo, Ernst R. Flueh, Yoshio Murai
Article
Geochemistry & Geophysics
Asbjorn Johan Breivik, Jan Inge Faleide, Rolf Mjelde, Ernst R. Flueh, Yoshio Murai
Article
Multidisciplinary Sciences
Junichi Miyazaki, Shinsuke Kawagucci, Akiko Makabe, Ayu Takahashi, Kazuya Kitada, Junji Torimoto, Yohei Matsui, Eiji Tasumi, Takazo Shibuya, Kentaro Nakamura, Shunsuke Horai, Shun Sato, Jun-ichiro Ishibashi, Hayato Kanzaki, Satoshi Nakagawa, Miho Hirai, Yoshihiro Takaki, Kyoko Okino, Hiromi KayamaWatanabe, Hidenori Kumagai, Chong Chen
ROYAL SOCIETY OPEN SCIENCE
(2017)
Article
Geochemistry & Geophysics
R. Azuma, R. Hino, Y. Ohta, Y. Ito, K. Mochizuki, K. Uehira, Y. Murai, T. Sato, T. Takanami, M. Shinohara, T. Kanazawa
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2018)
Article
Geochemistry & Geophysics
V Basch, A. Sanfilippo, C. Sani, Y. Ohara, J. Snow, O. Ishizuka, Y. Harigane, K. Michibayashi, A. Sen, N. Akizawa, K. Okino, M. Fujii, H. Yamashita
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2020)
Article
Geosciences, Multidisciplinary
Shiki Machida, Kentaro Nakamura, Tetsu Kogiso, Ryo Shimomura, Koichi Horinouchi, Kyoko Okino, Yasuhiro Kato
Summary: A wide area rich in ferromanganese nodules was discovered around Minamitorishima (Marcus) Island, providing a potential metal resource for Co, Ni, Mo, and W. By analyzing nodules samples and conducting chemical mapping, researchers identified compositional variations throughout the growth history of nodules, proposing a method for creating a multi-dimensional compositional map. The study revealed a detailed chemostratigraphy of the fine-scale ferromanganese oxide layers in the nodules, showing how missing sublayers in certain layers regulated nodule size and suggesting a key facies for chemostratigraphic correlations.
Article
Geosciences, Multidisciplinary
Ritoko Kikunaga, Ke-han Song, Shun Chiyonobu, Kazuhiko Fujita, Ryuichi Shinjo, Kyoko Okino
Summary: The late Cenozoic geohistory of the Ryukyu arc is closely related to the rifting history of the Okinawa Trough. The submarine geology and stratigraphy of areas around Kume Island provide key constraints to understand the timing and mode of Okinawa Trough rifting. Sedimentary rocks dredged near Kume Island show lithological similarities to formations in the Shimajiri Group and indicate a marine deltaic area extended towards the north during the early Pliocene to early Pleistocene.
Article
Geochemistry & Geophysics
A. Sen, J. E. Snow, Y. Ohark, K. Hirauchi, Y. Kouketsu, A. Sanfilippo, V Basch, Y. Harigane, M. Fujii, K. Okino, N. Akizawa
Summary: The Mado Megamullion in the Shikoku back-arc basin exhibits extensive deformation in mantle peridotites, with evidence of melt stagnation and mantle reaction. The wide range of compositions in spinels suggests involvement of multiple melts. The presence of magmatic high-temperature pargasitic amphibole implies unique crystallization processes in abyssal peridotites.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Geochemistry & Geophysics
Tetsuo Matsuno, Nobukazu Seama, Haruka P. Shindo, Yoshifumi Nogi, Kyoko Okino
Summary: The back-arc spreading at the southern Mariana is associated with enhanced melting in the upper mantle, as water is derived from the subducted Pacific slab. A marine magnetotelluric experiment revealed key processes of melting, dehydration, and dynamics in the upper mantle. The structure contrasts significantly with the central Mariana Trough, indicating that the horizontal distance between the spreading center and the root of the buoyant upwelling above the subducted slab is a key parameter in controlling mantle dynamics.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geosciences, Multidisciplinary
Norikatsu Akizawa, Yasuhiko Ohara, Kyoko Okino, Osamu Ishizuka, Hiroyuki Yamashita, Shiki Machida, Alessio Sanfilippo, Valentin Basch, Jonathan E. Snow, Atlanta Sen, Ken-ichi Hirauchi, Katsuyoshi Michibayashi, Yumiko Harigane, Masakazu Fujii, Hisashi Asanuma, Takafumi Hirata
Summary: This paper explores the evolutional process of back-arc basin (BAB) magma system at final spreading stage of extinct BAB, Shikoku Basin using a newly discovered oceanic core complex, the Mado Megamullion. The study shows that the compositional ranges and trends of the Mado Megamullion rocks are similar to those from slow-to-ultraslow spreading mid-ocean ridges, indicating subdued and episodic magma supply leading to extreme magma differentiation. The in-situ Pb isotope composition of magmatic brown amphibole in the oxide gabbro suggests that magmatic water was derived solely from the depleted source mantle for mid-ocean ridge basalt (MORB).
PROGRESS IN EARTH AND PLANETARY SCIENCE
(2021)
Article
Chemistry, Analytical
Takuya Sagawa, Akihiro Tamura, Kyoko Okino, Tomoaki Morishita
Summary: The single-pulse LA-ICP-MS method provides usable results for the determination of multiple trace elements in geological materials, despite having a higher relative standard deviation compared to conventional LA-ICP-MS analysis.
ANALYTICAL LETTERS
(2022)
Article
Geochemistry & Geophysics
Akihiro Tamura, Takuya Sagawa, Kyoko Okino, Tomoaki Morishita
Summary: The whole-rock trace-element compositions of igneous rocks provide primary geochemical information about their petrogenesis. However, the traditional fused-glass method is not suitable for Si-rich rocks. By adopting an MgO dilution process, homogeneous fused-glass samples of felsic rocks can be prepared and analyzed using LA-ICP-MS, with results consistent with reference data.
GEOCHEMICAL JOURNAL
(2022)
Article
Geosciences, Multidisciplinary
Ken-ichi Hirauchi, Izumi Segawa, Yui Kouketsu, Yumiko Harigane, Yasuhiko Ohara, Jonathan Snow, Atlanta Sen, Masakazu Fujii, Kyoko Okino
Summary: The ultramafic rocks in the Philippine Sea are strongly serpentinized and can be classified as harzburgite/lherzolite or dunite. They show high-temperature strain localization with elongated pyroxene porphyroclasts. During exhumation, impregnation by magmatic or hydrothermal fluids facilitated fluid-peridotite interactions via a fluid pathway formed by detachment fault zones.