Article
Multidisciplinary Sciences
Yi-Xiang Chen, Kun Zhou, Qiang He, Yong-Fei Zheng, Hans-Peter Schertl, Kun Chen
Summary: The ultrahigh-pressure metamorphism in the Sesia zone of Western Alps is reported for the first time, showing deep subduction of continental crust to mantle depths of >80 km. The deep subduction is driven by the distal push of continental breakup or seafloor spreading, rather than by the proximal pull of the subducting oceanic slab. The Sesia Zone provides an excellent target for exploring subduction dynamics in this tectonic setting.
NATIONAL SCIENCE REVIEW
(2023)
Article
Geosciences, Multidisciplinary
Philippe Agard
Summary: The geological record of the Alps represents the subduction process of short-lived and slowly closing North Atlantic-type oceans, demonstrating different subduction dynamics. There are noticeable differences between metasediment-and mafic/ultramafic-dominated units, with geological structures influenced by initial margin architecture and/or continental subduction.
EARTH-SCIENCE REVIEWS
(2021)
Article
Geochemistry & Geophysics
Benedict J. R. Harris, Jan C. M. De Hoog, Ralf Halama, Hans-Peter Schertl, Yi-Xiang Chen
Summary: This study investigates the sources and timing of fluid infiltration in the whiteschists from the Dora-Maira massif in the Western Alps. It utilizes boron isotopes and other fluid-mobile trace elements in phengite to understand the metasomatic fluid influx. The results suggest that a B-rich sediment-derived fluid is the main source of B in the whiteschists, while the source of the Mg-rich fluids cannot be determined. This study demonstrates the usefulness of in situ analyses in unraveling complex fluid-rock interaction histories.
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
(2023)
Article
Multidisciplinary Sciences
Michael A. Antonelli, Jillian Kendrick, Chris Yakymchuk, Martin Guitreau, Tushar Mittal, Frederic Moynier
Summary: This study analyzed calcium isotope and trace-element data from modern and ancient granitoids, finding that calcium isotope fractionations are primarily controlled by geothermal gradients, and suggesting that subduction-driven plate tectonic processes may have started on Earth prior to about 3.8 billion years ago.
NATURE COMMUNICATIONS
(2021)
Article
Geochemistry & Geophysics
Shelby T. Rader, Richard M. Gaschnig, Sean M. Newby, Gray E. Bebout, Michael J. Mirakian, Jeremy D. Owens
Summary: Thallium is an incompatible element that can be redistributed during various geological processes, yet its behavior during high-pressure/high-temperature metamorphism is not well quantified. This study found that with increasing metamorphic grade, the concentration of Tl in rocks remained constant while the epsilon Tl-205 values changed, indicating the importance of mineral reaction history in understanding the retention or loss of trace elements like Tl.
Article
Geochemistry & Geophysics
C. Caurant, B. Debret, B. Menez, C. Nicollet, P. Bouilhol
Summary: Variations of redox conditions during slab dehydration in subduction zones have been investigated in the Monviso meta-ophiolite. The study reveals that fO2 variations are influenced by the position of the lithologies in the slab, with deep-seated lithologies showing high fO2 conditions and paleoseafloor lithologies exhibiting low fO2 conditions.
Article
Geochemistry & Geophysics
Clement Herviou, Philippe Agard, Alexis Plunder, Kevin Mendes, Anne Verlaguet, Damien Deldicque, Nadaya Cubas
Summary: This study provides a detailed framework of the peak metamorphic conditions experienced by subducted slow-spreading oceanic lithosphere in the Liguro-Piemont domain of the Western Alps. High-resolution mapping confirms the increase in metamorphic grade from west to east. The lithostratigraphic, structural, and radiochronological data help refine the origin of these tectonic units within the former oceanic domain. The results reveal a trimodal distribution of units with different metamorphic conditions.
Editorial Material
Geosciences, Multidisciplinary
K. A. Cutts
Summary: The recent study by Chaves and Porcher in Gondwana Research discusses the presence of 2.2 Ga eclogite facies rocks in the Itaguara Sequence in Brazil. By utilizing P-T phase modelling, they confirm that these rocks are not retrogressed eclogites and suggest peak conditions were likely in the amphibolite facies. This work emphasizes the importance of carefully evaluating petrography and thermodynamic investigations when declaring eclogite facies conditions, particularly in Paleoproterozoic terrains.
Article
Geochemistry & Geophysics
Jean-Baptiste Jacob, Emilie Janots, Stephane Guillot, Daniela Rubatto, Kevin Freville, Jeremie Melleton, Michel Faure
Summary: The Oisans-Pelvoux massif in the Western Alps records high temperature metamorphism and intense migmatization during the Variscan orogeny. New findings of high pressure mafic granulites provide insights into the early evolution of the unit, with relics of Mn-rich garnet cores revealing prograde stages and HP assemblages indicating peak-P conditions and subsequent decompression to HT granulite-facies conditions.
Article
Geochemistry & Geophysics
Enrico Cannao, Marco Scambelluri, Othmar Muentener, Benita Putlitz, Samuele Agostini
Summary: The trace element and isotopic compositions of exhumed high-pressure mafic rocks provide important information on chemical processes in subduction zones. In this study, the boron isotopic composition of eclogitic mafic rocks from the Voltri Massif, Italy, was investigated to understand oceanic inheritance and subduction-related processes. The results suggest that the negative 811B signatures in eclogites are mainly caused by dehydration processes during subduction, while positive 811B signatures are likely inherited from oceanic sources or influenced by fluids released by serpentinites.
Article
Geosciences, Multidisciplinary
Laura C. Reynolds, Alexander R. Simms, Thomas K. Rockwell, Yusuke Yokoyama, Yosuke Miyairi, Alexandra Hangsterfer
Summary: This study presents evidence of late Holocene coseismic subsidence in a structural estuary in southern California, suggesting a longer recovery process compared to estuaries with larger tidal ranges and wetter climates.
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
(2022)
Article
Geochemistry & Geophysics
Yuan-Ru Qu, Sheng-Ao Liu, Vincent Busigny, Ze-Zhou Wang, Fang-Zhen Teng
Summary: Carbonate-silicate interaction in subduction channels affects the properties of subducting carbon and the fate of carbonates in subduction zones. Geochemical evidence for this interaction is limited, but zinc isotopes provide a potential way to investigate it. The study shows that carbonate components in sediments can be retained at depths below 90 km in subduction zones, and the zinc isotopes can serve as a proxy for the storage depth of subducting carbonates.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
Giampaolo Proietti, Alessia Conti, Marco Cuffaro, Paolo Esestime, Sabina Bigi
Summary: The study investigated the evolution of the western margin of the Calabrian Arc through analyzing the configuration of sedimentary basins and their relationship with tectonic structures. Research focused on offshore sedimentary basins east of Sicily along the Alfeo Fault System, revealing a direct relationship between fault activity and basin geometry. Additionally, results suggest a link between fault kinematics and subduction-related faults in other subduction systems.
Article
Geosciences, Multidisciplinary
Nikola Stankovic, Taras Gerya, Vesna Cvetkov, Vladica Cvetkovic
Summary: The ophiolites of the Balkan Peninsula, including the Western and Eastern Vardar ophiolites, are believed to have formed due to the closure of the Vardar branch of the Tethys Ocean. This study uses numerical modeling to test the hypothesis that a single intra-oceanic subduction can explain the origin and emplacement of both ophiolite belts. The results suggest that the subduction can account for the westward obduction of the Western Vardar ophiolites and the complex active margin processes along the western rim of the European plate.
Article
Geochemistry & Geophysics
Gabe S. Epstein, Gray E. Bebout, Samuel Angiboust
Summary: Fluid flow along Western Alps paleo-subduction interfaces in NW Italy was focused by high strain rates, leading to extensive chemical alteration and shifts in O isotope compositions due to fluid-rock interactions at high-P, low-T conditions. The flushing of structures by H2O-rich fluids resulted in metasomatic reaction zones and prominent reactions among various rock types. Evidence suggests pressure solution and partitioning of fluid-mobile elements, with fluid flow leading to carbonate and SiO2 deposition proximal to structures.
Article
Geography
Edoardo Sanita, Jean-Marc Lardeaux, Michele Marroni, Guido Gosso, Luca Pandolfi
Summary: This study highlights the finite strain pattern recorded in Marguareis Unit through accurate geological mapping and structural analysis. The superposed tectonic structures developed during the Alpine collision are exceptionally well preserved in the area of interest. The structural frame of the Marguareis Unit results from superposition of fourfold systems, later segmented by brittle faults without significant displacements.
Article
Geosciences, Multidisciplinary
Edoardo Sanita, Maria Di Rosa, Jean Marc Lardeaux, Michele Marroni, Luca Pandolfi
Summary: This study quantifies for the first time the metamorphic peak conditions of the Marguareis Unit and finds that it recorded high-pressure and low-temperature conditions during the Alpine collision.
Article
Geosciences, Multidisciplinary
A. S. Tabaud, J. M. Lardeaux, M. Corsini
Summary: The Maures-Tanneron Massif provides new constraints on the pre-Variscan metaigneous rocks in the southern Variscan Belt. The study combines geochemical analysis and U-Pb isotopic data on zircon to understand the pre-Variscan evolution and enhance knowledge of the southern Variscan domain. The results suggest that the studied samples originated from a high-K calc-alkaline granodiorite emplaced in a subduction zone, possibly a continental arc setting. The age of the protolith is estimated to be around 590 million years ago, based on zircon U-Pb dating.
INTERNATIONAL JOURNAL OF EARTH SCIENCES
(2023)
Article
Geosciences, Multidisciplinary
Marco Filippi, Davide Zanoni, Gisella Rebay, Manuel Roda, Alessandro Regorda, Jean-Marc Lardeaux, Maria Iole Spalla
Summary: This article provides evidence of Alpine metamorphism in the northern part of the central Southern Alps. It suggests that this region reached a certain thermal state and obtained metamorphic conditions during the Alpine evolution.
