Article
Geochemistry & Geophysics
Dong Fu, Bo Huang, Simon A. Wilde, Tim E. Johnson, Ali Polat, Brian F. Windley, Zhaochu Hu, Zhipeng Zhou, Timothy M. Kusky
Summary: The study reveals that the North Qilian back-arc basin in the northeastern region of the North Qilian orogenic belt underwent an early spreading phase and subsequent closure through two subduction episodes. The findings highlight the crucial role of back-arc oceanic crust subduction in the closure of back-arc basins, and the complex evolutionary tempo of such basins in Earth history.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
Yumiko Harigane, Katsuyoshi Michibayashi, Tomoaki Morishita, Akihiro Tamura, Satoshi Hashimoto, Jonathan E. Snow
Summary: By analyzing mantle peridotites from the Gakkel Ridge system, researchers were able to identify high-temperature crystal-plastic deformation and lower-temperature mylonitization processes. These processes indicate a transition from mantle flow to shear zone formation.
Article
Geochemistry & Geophysics
Mohamad A. Ismail, Ayman E. Maurice, Paul D. Asimow, Moustafa E. Gharib, M. J. Wilner, Hussam A. Selim
Summary: This study in the Neoproterozoic region of eastern Egypt reveals the existence of ultramafic rock sequences, and through measuring the minerals and elements within them, insights can be gained into the formation process of the minerals and the characteristics of magmatic activity.
Article
Geosciences, Multidisciplinary
L. Cocchi, F. Muccini, C. Palmiotto, G. Ventura
Summary: This study investigates the morphology and magnetic characteristics of the Vavilov seamount and reveals its connection to the asymmetric opening of the Vavilov back-arc basin. The seamount represents the final stage of asymmetric expansion, with its plumbing system consisting of early dike swarms and a younger central reservoir. The findings highlight the asymmetry between the seamount and the back-arc basin.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Changyeol Lee, Ikuko Wada
Summary: The research shows that the cessation of back-arc spreading leads to the formation of nascent lithospheric drips, which interfere with the flow of mantle beneath the arc and result in alternating hot and cold regions, promoting volcano clustering. This explains the time offset between back-arc spreading and volcano clustering in Northeast Japan and Izu-Bonin.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geochemistry & Geophysics
Yuan Li, Ruibao Li, Shengbiao Yang, Jian Zhang, Jingsui Yang
Summary: This study investigates the tectonic setting of the Xigaze ophiolite in southern Tibet and reveals a three-stage magma injection during the crust formation, providing insights into the crustal evolution during the Early Cretaceous.
Article
Geochemistry & Geophysics
Zihua Cheng, Fan Zhang, Jian Lin, Weiwei Ding, Xubo Zhang
Summary: This study investigates the evolution of forearc and backarc spreading in relation to Subduction Initiation (SI), using the unique evolution history of the Izu-Bonin-Mariana subduction system (IBM). Based on plate motion history and 2D thermomechanical models, the early stages of SI as well as the evolutions of forearc and backarc spreading were simulated. A new model with a delayed convergence rate after approximately 5 million years of SI was proposed to explain the observed phenomena in the IBM.
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
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
Geosciences, Multidisciplinary
Shoma Oya, Katsuyoshi Michibayashi, Yasuhiko Ohara, Fernando Martinez, Fatma Kourim, Hao-Yang Lee, Kohei Nimura
Summary: Peridotites were discovered on the southwestern slope of the 139 degrees E Ridge using the Shinkai6500 submersible. The peridotites showed differences in textures, crystal-fabrics, and geochemical features with respect to their depths. The presence of a ductile shear zone and the similarity with the Parece Vela Basin peridotites suggest that the Parece Vela Basin mantle is exposed on the inner slope of the westernmost Mariana Trench, possibly due to the collision of the Caroline Ridge.
PROGRESS IN EARTH AND PLANETARY SCIENCE
(2022)
Article
Geochemistry & Geophysics
Yanhong Chen, Yaoling Niu, Qiqi Xue, Yajie Gao, Paterno Castillo
Summary: The geology and magmatism of the northern Mariana Trough (NMT) represent a type example for the development of a back-arc basin. Studies have shown systematic variations in Fe isotopes and element compositions of basalts from south to north, revealing source variations and contributions of slab materials and mantle characteristics. This tectonic-magma evolution is manifested through the geochemistry and petrology of the NMTB samples, highlighting the importance of lithospheric characteristics in subduction initiation.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geochemistry & Geophysics
Mohamed Zaki Khedr, Ahmed A. Al Desouky, Samir Kamh, Christoph Hauzenberger, Shoji Arai, Akihiro Tamura, Scott A. Whattam, Tomoaki Morishita, El Saeed R. Lasheen, Amr El-Awady
Summary: This study successfully identified the characteristics of Gerf ophiolitic rocks in the Southern Eastern Desert of Egypt using satellite data, and determined the regional geological structure. The rocks in this area have low TiO2, Al2O3, and CaO content, but high Ni and Cr content, indicating the influence of melting processes.
Article
Oceanography
Niyati G. Kalangutkar, Sridhar D. Iyer
Summary: In this study, we present data on mineral assemblages and composition of pumices in the Central Indian Ocean Basin (CIOB). By analyzing the presence of various minerals and quartz and glass in the pumices, we identified eight groups. We also discovered new minerals, such as pigeonite, fayalite, and ulvospinel in these pumices. Based on our analysis, we determined possible sources of the CIOB pumices and found some pumices that do not correlate to known volcanic eruptions, suggesting unidentified sources.
ACTA OCEANOLOGICA SINICA
(2023)
Article
Geosciences, Multidisciplinary
Kazuhiko Ishii, Simon R. Wallis
Summary: Back-arc spreading is a non-steady-state process characterized by cyclic spreading in specific regions. It starts with rifting within the volcanic arc before shifting to the back-arc region, undergoing a well-defined phase of spreading. The thickness and strength of the subducted slab play important roles in determining the type of back-arc spreading.
PROGRESS IN EARTH AND PLANETARY SCIENCE
(2022)
Article
Geosciences, Multidisciplinary
Libeesh Lukose, Dibyendu Dutta, Mayashri Rajkakati, Arindam Guha, Santanu Kumar Bhowmik
Summary: This study investigates the constituent minerals of different kinds of ultramafic rock samples through petrographic, mineral, and compositional studies. It identifies the dominant absorption features of olivine and different pyroxenes in these rocks. The study also recognizes absorption bands indicative of secondary hydrous minerals associated with alteration. The findings have significance in interpreting remotely sensed data and identifying fossil subduction systems.
JOURNAL OF EARTH SYSTEM SCIENCE
(2023)
Article
Geosciences, Multidisciplinary
Hadi Shafaii Moghadam, R. J. Stern, W. L. Griffin, M. Z. Khedr, M. Kirchenbaur, C. J. Ottley, S. A. Whattam, J- Kimura, G. Ghorbani, S. Gain, S. Y. O'Reilly, A. Tamura
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
(2020)
Article
Geochemistry & Geophysics
Hadi Shafaii Moghadam, Q. L. Li, W. L. Griffin, R. J. Stern, O. Ishizuka, H. Henry, F. Lucci, S. Y. O'Reilly, G. Ghorbani
EARTH AND PLANETARY SCIENCE LETTERS
(2020)
Article
Geochemistry & Geophysics
R. Esmaeili, W. Xiao, W. L. Griffin, H. Shafaii Moghadam, Z. Zhang, M. Ebrahimi, J. Zhang, B. Wan, S. Ao, S. Bhandari
Article
Geochemistry & Geophysics
H. Shafaii Moghadam, Q. L. Li, X. H. Li, R. J. Stern, G. Levresse, J. F. Santos, M. Lopez Martinez, M. N. Ducea, G. Ghorbani, A. Hassannezhad
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2020)
Article
Geosciences, Multidisciplinary
Hadi Shafaii Moghadam, Qiu-li Li, William L. Griffin, Orhan Karsli, Jose F. Santos, C. J. Ottley, Ghasem Ghorbani, Suzanne Y. O'Reilly
Article
Geochemistry & Geophysics
Fatemeh Sepidbar, Hadi Shafaii Moghadam, Congying Li, Robert J. Stern, Peng Jiantang, Yusef Vesali
Article
Geochemistry & Geophysics
Hadi Shafaii Moghadam, Qiu-Li Li, William L. Griffin, Robert J. Stern, Massimo Chiaradia, Orhan Karsli, Ghasem Ghorbani, S. Y. O'Reilly, Mehrdad Pourmohsen
Article
Geochemistry & Geophysics
H. Shafaii Moghadam, Q. L. Li, W. L. Griffin, R. J. Stern, J. F. Santos, F. Lucci, M. Beyarslan, G. Ghorbani, A. Ravankhah, R. Tilhac, S. Y. O'Reilly
Summary: The crust of Iran and Anatolia was mainly formed during the Cadomian crust-forming event from ca 620 Ma to ca 500 Ma, as a result of subduction of oceanic lithosphere beneath northern Gondwana. Cadomian magmatism included calc-alkaline igneous rocks of arc affinity in the main arc and alkalic igneous rocks in a back-arc setting, associated with sedimentary rocks, with basaltic magmas as the main input.
Review
Astronomy & Astrophysics
Robert J. Stern, Hadi Shafaii Moghadam, Mortaza Pirouz, Walter Mooney
Summary: Iran serves as a remarkable geoscientific laboratory for studying the full range of processes that form and modify the continental crust. Its crustal evolution, from forming as a magmatic arc on the northern margin of Gondwana to colliding with Arabia in the Paleogene era, has led to significant economic resources and earthquake hazards. Iran's Cenozoic evolution preserves the main elements of a convergent plate margin, including foredeep, accretionary prism, and magmatic arc.
ANNUAL REVIEW OF EARTH AND PLANETARY SCIENCES, VOL 49, 2021
(2021)
Article
Geochemistry & Geophysics
H. S. Moghadam, Q. L. Li, M. Kirchenbaur, D. Garbe-Schoenberg, F. Lucci, W. L. Griffin, G. Ghorbani
Summary: The study reveals that collisional magmatism in the NE Iran back-arc began around 24 million years ago, with magmatism starting as early as the Late Cretaceous and continuing until the Pleistocene. The collisional igneous rocks exhibit bimodal characteristics, with significant isotopic differences between basaltic-andesitic and dacitic-rhyolitic components, suggesting a role of fractional crystallization and assimilation-fractional crystallization in the genesis of felsic rocks. Trace element and isotopic modeling point to triggers of magmatism in NE Iran being a depleted to enriched mantle and the Cadomian continental crust of Iran, with temporal magmatic variations observed from Late Cretaceous to Pleistocene.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Geochemistry & Geophysics
Hadi Shafaii Moghadam, Robert J. Stern
Summary: Subduction initiation leads to plate sinking and extensional stress on the overriding plate. The Late Cretaceous forearc ophiolites in Iran demonstrate that subduction initiation can cause strong extension over a wider region than previously thought.
Article
Geology
H. S. Moghadam, Q. L. Li, R. J. Stern, W. L. Griffin, S. Y. O'Reilly
Summary: Geochronological and geochemical data suggest that Late Cretaceous Zagros ophiolites in southwestern Iran were formed through forearc seafloor spreading. These ophiolites span a belt of approximately 3000 km from Cyprus to Oman, passing through Turkey, Syria, Iran, and the UAE. The U-Pb zircon magmatic ages of samples from the Kermanshah ophiolite indicate ophiolite formation occurred between 98 and 96 million years ago. The presence of zircon xenocrysts in the Kermanshah ophiolite suggests its formation adjacent to the Iranian continent during Late Cretaceous subduction initiation.
INTERNATIONAL GEOLOGY REVIEW
(2022)
Article
Geochemistry & Geophysics
H. Shafaii Moghadam, K. Hoernle, F. Hauff, D. Garbe-Schoenberg, J. A. Pfaender
Summary: High Na-to K-alkaline magmatism is common in the rear-arc region of the Cenozoic Urumieh-Dokhtar Magmatic Belt in Iran. The Kleybar area in NW Iran shows Middle Eocene magmatic activity with diverse rock types and significant isotopic variations, enriched in alkalis and light rare earth elements.
Article
Geochemistry & Geophysics
Hadi Shafaii Moghadam, William L. Griffin, Jose F. Santos, Ren-Xu Chen, Orhan Karsli, Federico Lucci, Fatemeh Sepidbar, S. Y. O'Reilly
Summary: This study focuses on the magmatic rocks in the Nagisun area of the southeast segment of the Urumieh-Dokhtar Magmatic Belt (UDMB) in Iran. The rocks exhibit characteristics similar to volcanic arcs based on their geochemical and isotopic compositions. The results provide insights into the formation mechanisms and origin of these rocks.
Article
Geosciences, Multidisciplinary
Siavash Omidianfar, Iman Monsef, Mohammad Rahgoshay, Hadi Shafaii Moghadam, Brian Cousens, Ming Chen, Shahrokh Rajabpour, Jianping Zheng
Summary: Eocene-Oligocene magmatic rocks in the region south of Birjand, eastern Iran, provide valuable insights into the magmatic and geodynamic history of the area during the Cenozoic. The rocks are predominantly volcanic and intrusive, with geochemical characteristics indicative of subduction-related magmatism. The ages of these rocks range from approximately 46 Ma to 25 Ma, and their formation is likely linked to the subduction of the Neo-Tethyan oceanic lithosphere and subsequent asthenospheric upwelling. The interaction between the parental magmas and the continental crust during ascent likely played a role in the formation of these magmatic rocks.
GEOLOGICAL MAGAZINE
(2023)