Article
Geochemistry & Geophysics
Yoshio Fukao, Tatsuya Kubota, Hiroko Sugioka, Aki Ito, Takashi Tonegawa, Hajime Shiobara, Mikiya Yamashita, Tatsuhiko Saito
Summary: The study deployed ocean bottom pressure gauges at the Izu-Bonin Trench and observed that subduction mainly occurs through aseismic slip. Two much larger aseismic slip events were detected near a Mw6.0 thrust earthquake, with the total moment 17 times larger than that of the mainshock. This kind of slip may represent a transitional regime in the subduction zone, where slow slip events are expected to occur near its boundaries with stable sliding and unstable seismic slip regimes.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geosciences, Multidisciplinary
Ryan J. Waldman, Kathleen M. Marsaglia, Rosemary Hickey-Vargas, Osamu Ishizuka, Kyle E. Johnson, Anders McCarthy, Gene Yogodzinski, Eshita Samajpati, He Li, Kate Laxton, Ivan P. Savov, Sebastien Meffre, Richard J. Arculus, Alexandre N. Bandini, Andrew P. Barth, Kara Bogus, Philipp A. Brandl, Michael Gurnis, Fuqing Jiang
Summary: The oldest known and intact sedimentary record of a nascent intraoceanic arc was discovered at International Ocean Discovery Program Site U1438. The geological sequence includes mudstone, volcaniclastic deposits, intrusion of volcanic magma, island arc magmatism, indicating the changes and activities at the early stage of subduction initiation.
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
(2021)
Article
Geochemistry & Geophysics
William W. Sager, Claire Carvallo
Summary: The Philippine Sea plate is a part of the east Asian plate mosaic, and its past motions can only be determined from paleomagnetic data. The International Ocean Discovery Program (IODP) Expedition 352 studied the Izu-Bonin forearc, and found that the paleolatitude of the area was on the equator with a northward drift of approximately 28°, consistent with other forearc sites of similar age. Additionally, some samples in the cored sections were remagnetized after approximately 30 million years, suggesting an unknown tectonic event.
Article
Geosciences, Multidisciplinary
Wasja Bloch, Bernd Schurr, Xiaohui Yuan, Lothar Ratschbacher, Sanaa Reuter, Sofia-Katerina Kufner, Qiang Xu, Junmeng Zhao
Summary: The research data suggests that the location and shape of the Pamir plateau may be caused by the forceful indentation of the Indian mantle lithosphere, resulting in complex interactions with the Asian slab. The Indian mantle indenter may lead to the delamination and overturning of the Asian slab, while also affecting the lithosphere of the Tarim basin.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geochemistry & Geophysics
Suzanna H. A. van de Lagemaat, Daniel Pastor-Galan, Bas B. G. Zanderink, Maria J. Z. Villareal, John W. Jenson, Mark J. Dekkers, Douwe J. J. van Hinsbergen
Summary: The kinematic history of the Philippine Sea Plate is crucial for understanding its geological record and paleogeography. However, reconstructing the plate's history is difficult due to its surroundings by subduction zones. In this study, paleomagnetic data from Guam and reevaluated published data were used to determine plate motion. The results suggest that rotations of the plate may be permitted but are not required. The study highlights the importance of geological constraints for reconstructing plate motion.
Article
Geochemistry & Geophysics
Kun Guo, Xiaoyuan Wang, Shuai Chen, Luning Shang, Bingquan Liu, Xia Zhang, Zhiqing Lai
Summary: The Kueishantao (KST) area, located at the tectonic junction of the Okinawa Trough and the Ryukyu arc, is an ideal location to study the influence of the lower crust on the generation of back-arc magmas. Research shows that the KST andesitic magma is likely sourced from the lower continental crust.
Article
Geochemistry & Geophysics
John W. Shervais, Mark K. Reagan, Marguerite Godard, Julie Prytulak, Jeffrey G. Ryan, Julian A. Pearce, Renat R. Almeev, Hongyan Li, Emily Haugen, Timothy Chapman, Walter Kurz, Wendy R. Nelson, Daniel E. Heaton, Maria Kirchenbaur, Kenji Shimizu, Tetsuya Sakuyama, Scott K. Vetter, Yibing Li, Scott Whattam
Summary: The International Ocean Discovery Program Expedition 352 collected comprehensive data on over 800 meters of in situ oceanic crust comprising boninite and boninite-series lavas in the Izu-Bonin forearc. The lavas were categorized into high-silica boninite, low-silica boninite, and basaltic boninite based on their chemical compositions, with distinct axial and off-axis lava types identified through chemostratigraphic analysis. This study provides insights into the origins and petrogenesis of these unusual boninite lavas in the forearc setting.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Geochemistry & Geophysics
Anders McCarthy, Gene M. Yogodzinski, Michael Bizimis, Ivan P. Savov, Rosemary Hickey-Vargas, Richard Arculus, Osamu Ishizuka
Summary: The study indicates that the evolution of magmatic sources in the early Izu-Bonin arc underwent significant changes around 35 Ma, with trace element ratios and magma compositions gradually increasing in younger samples within the 40-30 Ma time window, influenced by the addition of subducted Pacific MORB melt or supercritical fluid.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geosciences, Multidisciplinary
Yuki Kusano, Osamu Ishizuka, Rosemary Hickey-Vargas, Richard J. Arculus
Summary: The study of volcanic stratigraphy at the IODP Site U1438 in the Amami Sankaku Basin revealed the development of lava accretion and ridge topography on the Philippine Sea plate around 49 million years ago. This indicates a correlation between volcanic activity and plate evolution during the early stages of crustal development in a supra-subduction zone.
Article
Geosciences, Multidisciplinary
Wei Gong, Xiaodian Jiang, Junhui Xing, Chong Xu, Hao Zhang, Long An, Chaoyang Li
Summary: This study determined the stress field distribution at the outer-rise region of the Izu-Bonin subduction zone through waveform inversion, revealing the seismic activity characteristics and diverse bending deformation of the subducting plate. Modeling flexural bending showed a decrease in effective elastic thickness along the trench strike, explaining the heterogeneous seismic activity within the subduction zone.
GEOLOGICAL JOURNAL
(2021)
Article
Multidisciplinary Sciences
Hong-Yan Li, Rui-Peng Zhao, Jie Li, Yoshihiko Tamura, Christopher Spencer, Robert J. Stern, Jeffrey G. Ryan, Yi-Gang Xu
Summary: A deep neural network is used to automatically extract ground deformation from Interferometric Synthetic Aperture Radar time series. The method detects 2 mm deformation transients over the North Anatolian Fault and reveals a previously unrecognized slow earthquake. The study investigates how serpentinites in the forearc mantle and subducted lithosphere enrich the subarc mantle source of arc magmas.
NATURE COMMUNICATIONS
(2021)
Article
Geochemistry & Geophysics
Shuai Yuan, He Li, Richard J. Arculus, Yongsheng He, Shan Ke, Weidong Sun
Summary: This study investigates the magnesium isotopic compositions (δ26Mg) of basalts recovered from the Amami Sankaku Basin (ASB) in the Ryukyu Trench. The δ26Mg values of ASB basalts are systematically higher than those of mid-ocean ridge basalts (MORBs), indicating an enrichment in heavy Mg isotopes in the mantle source. The presence of water-rich serpentinite components in the mantle suggests a new mechanism for partial melting of a refractory mantle source without the influence of subducted materials, which has implications for the initiation of plate subduction.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geochemistry & Geophysics
Ping Zhang, Meghan S. Miller, Caroline M. Eakin
Summary: This study analyzed the structural, deformational, and compositional variations along the Sunda-Banda volcanic arc transitional zone, presenting distinct along-arc spatial variations in shear wave velocity and anisotropic structure within the crust and mantle wedge above the subducting slab.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geosciences, Multidisciplinary
C. Chiarabba, I. Menichelli, I. Bianchi, G. Giacomuzzi, P. De Gori
Summary: Studies on the Alpine-Himalayan collision system show that a significant portion of the continental crust is subducted, while some material is accreted in the orogens. The Apennines orogen is an ideal case for studying the evolution of such processes, thanks to high-quality seismic images.
FRONTIERS IN EARTH SCIENCE
(2023)
Article
Geochemistry & Geophysics
Christopher A. Parendo, Stein B. Jacobsen, Jun-Ichi Kimura, Rex N. Taylor
Summary: In subduction zones, fluids rising from the slab to the mantle cause metasomatism and flux melting of the mantle to produce arc magmas. The study investigates the transport of K in subduction zones by analyzing K stable isotope variations in lavas of the Izu arc. Results show isotopically heavy K in Izu lavas relative to midocean ridge basalt-source upper mantle, with delta(41)Kvalues decreasing across the arc, suggesting isotopic fractionation during slab dehydration and progressive breakdown of certain phases. The study also explores the role of different source materials and the possibility of slab signal attenuation in the rear arc due to fluid-mantle interaction.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)