Article
Geochemistry & Geophysics
Andrew J. Smye, Spencer M. Seman, Marco Scambelluri, Paul G. Starr, Laura Federico
Summary: The study in the Western Alps reveals important information about the Alpine orogeny and exhumation in the Voltri Unit and adjacent Tertiary Piedmont Basin. Petrological and geochemical data from Fe-Ti metagabbros and quartzite samples show a record of prolonged high-pressure metamorphism and the timing of its formation and exhumation. The contemporaneous sedimentation and metamorphism processes indicate a new model for lithospheric tectonics, with the assemblage of high-pressure material and the exhumation mechanism being better understood.
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
(2021)
Article
Geochemistry & Geophysics
Bertram Uunk, Fraukje Brouwer, Manuel De Paz-Alvarez, Kirsten van Zuilen, Rosanne Huybens, Reinier van 't Veer, Jan Wijbrans
Summary: This study constrains the timing and conditions of subducted, exhumed, and exposed high pressure metamorphic rocks on the Cyclades islands in Greece, showing a progressive subduction and exhumation resulting in imbrication of a former continental margin. Different mechanisms may trigger consistent exhumation for mechanically strong rocks and weakly coupled supracrustal rocks.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Zhi Wang, Jian Lin
Summary: The frequent occurrence of large thrust earthquakes and subsequent tsunamis in a subduction zone are attributed to multiple factors, including structural heterogeneity, fluid saturation, and topographic variations of the subducting oceanic plate. This study investigates the impact of these factors on the 2021 Mw 7.1 Fukushima-Oki earthquake and interplate seismic coupling in the northeastern Japan subduction zone. The results reveal that high-V zones with high-density thrust earthquakes indicate strong interplate seismic coupling, while low-V patches reflect weak interplate coupling or decoupling. Additionally, seamount subduction plays a significant role in seismography and the mechanical strength variation of interplate coupling in the forearc seismogenic zone.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Mohammad Yuzariyadi, Kosuke Heki
Summary: This study examines the increase of landward surface velocity following megathrust earthquakes in four subduction zones, including NE Japan, Chile, Sumatra, and Mexico, showing that such changes occurred with a range of a few mm/yr to up to 1 cm/yr in adjacent segments. The increased region of landward movements extends with spatial decay, reaching distances comparable to the along-strike fault length. However, the temporal decay of the increased velocity is not clear at present, suggesting a possible correlation with earthquake magnitude and fault slip.
Article
Geology
Wenchao Yu, Giacomo Oggiano, Giovanni Mongelli, Jintao Zhou, Roberto Buccione, Lingtong Xu, Paola Mameli, Yuansheng Du
Summary: Bauxite deposits in Italy are mainly found in the Sardinia and Adria regions within Cretaceous carbonate sequences. The parental affinity of these deposits has long been disputed, with four potential sources proposed. This study analyzed the detrital zircon U-Pb ages and Hf isotope values of Cretaceous bauxites in these regions, along with published geochemical data, to discuss their provenances. The results showed that the bauxite deposits in Sardinia originated from the Variscan metasedimentary basement, while those in Adria were mainly supplied by coeval volcanic materials.
ORE GEOLOGY REVIEWS
(2023)
Article
Geosciences, Multidisciplinary
Melek Ural, Kaan Sayit, Osman Ersin Koralay, Mehmet Cemal Goncuoglu
Summary: During the Late Cretaceous in the Eastern Mediterranean, the closure of the northern branch of the southern Neotethys was caused by multiple northward subductions. This resulted in the formation of the Baskil continental arc and the Yuksekova Complex, representing different tectonic settings and sources.
ACTA GEOLOGICA SINICA-ENGLISH EDITION
(2021)
Article
Geosciences, Multidisciplinary
Amin Jafari, Habibollah Ghasemi
Summary: This study presents a descriptive model of the Sabzevar Oceanic Basin (SOB) in Northeast Iran, based on detailed geological evidence and reconstruction of its evolutionary geologic history. The evidence suggests that the SOB formed during Late Triassic-Early Jurassic times as a result of extensional movements following the subduction initiation of the Iranian sector of the NeoTethys in the Zagros orogenic belt and closed in the Paleocene after NeoTethyan early continental collision. The magmatic activity in the SOB shows a progressive spatio-temporal evolution with distinct ranges of magma series.
JOURNAL OF ASIAN EARTH SCIENCES
(2023)
Article
Geosciences, Multidisciplinary
Guisheng Zhou, Jianxin Zhang, C. G. Mattinson, Zenglong Lu, Xiaohong Mao, Xia Teng
Summary: This study identifies two ultrahigh pressure metamorphic units in the western North Qaidam Mountains, namely YKU and LLU. YKU is mainly composed of medium-low temperature eclogites and metapelites, while LLU primarily consists of granulitized eclogites and pelitic granulites. The research shows that these two adjacent metamorphic units underwent different exhumation pathways.
Article
Geochemistry & Geophysics
Tao Gou, Shaohong Xia, Zhouchuan Huang, Dapeng Zhao
Summary: The study in the Alaska-Aleutian forearc region found uneven hydration levels in the subducting plate, with variations correlated to seismic trends. Slow earthquakes occurring between the hydrated slab and the overriding mantle suggest that hydration and dehydration in the lower plate may influence interplate coupling and seismic behaviors.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geology
Philip Gross, Jan Pleuger, Mark R. Handy, Marisa Germer, Timm John
Summary: This study investigates the evolution of the three-dimensional thermal structure of a palaeo-subduction channel in the Eastern Alps. By analyzing temperature contours and rock metamorphism, important discoveries are made regarding the evolution of the subduction-related temperature field.
JOURNAL OF METAMORPHIC GEOLOGY
(2021)
Article
Geochemistry & Geophysics
Mathieu Rodriguez, Maelis Arnould, Nicolas Coltice, Mathieu Soret
Summary: The head of a mantle plume weakens oceanic lithosphere through buoyancy forces and excess temperature, leading to intra-oceanic subductions. During the Late Cretaceous, the Neotethys subduction records suggest that plume-triggered subduction retreated towards the continental margins of Arabia and India. The sequential segmentation and diachronous deactivation of this subduction drove plate reorganization events in the Indian Ocean from the Late Cretaceous to the Eocene.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geochemistry & Geophysics
Scott Jess, Eva Enkelmann, William A. Matthews
Summary: The timing of surface uplift in the Appalachian Mountains has been a topic of controversy. This study aims to resolve the exhumation history of the region using detrital laser ablation apatite (U-Th-Sm)/He dating. Results show a majority of Cretaceous dates, indicating a lack of significant Cenozoic exhumation. These findings have implications for understanding surface uplift and landscape evolution.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Jennifer S. Gorce, Mark J. Caddick, Ethan F. Baxter, Besim Dragovic, John C. Schumacher, Robert J. Bodnar, Jamie F. Kendall
Summary: Constraining the conditions and mechanisms of early exhumation within subduction zones is challenging, as individual rocks may not provide all necessary parameters. A study in Syros, Greece, using thermobarometric and geochronologic data from a single sample reveals distinct phases of garnet growth indicating evidence of initial exhumation of parts of the Cycladic Blueschist Unit.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Geosciences, Multidisciplinary
Johannes Glodny, Uwe Ring
Summary: This study discusses the assembly and tectonochronology of the Cycladic Blueschist Unit (CBU) in the central Aegean Sea region, Greece. Based on geochronologic data from the Cycladic islands of Tinos, Syros and Sifnos, the authors propose that the CBU is a composite, subduction-related stack of nappes. They find that the nappes were sequentially accreted between -55 and -30 Ma and each nappe was exhumed and experienced greenschist-facies overprinting. The authors also suggest that the under thrusting of the External Hellenides during the early Oligocene caused significant shortening and out-of-sequence thrusting.
EARTH-SCIENCE REVIEWS
(2022)
Article
Geochemistry & Geophysics
Bahman Rahimzadeh, Shahryar Mahmoudi, Fernando Corfu, Vahid Ahadnejad, Albrecht Von Quadt
Summary: The Sanandaj-Sirjan metamorphic-magmatic Zone (SaSZ) is the Mesozoic active continental margin between the Arabian plate and the Iranian plateau. It evolved at the margin of ancient Ediacaran basement, with an age of 557 Ma for a trondhjemite. The Mesozoic activity of the SaSZ was most intense in the Jurassic period between 170 and 150 Ma.