Articles | Volume 9, issue 1
https://doi.org/10.5194/se-9-191-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/se-9-191-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
26 Feb 2018
Research article |
| 26 Feb 2018
| 26 Feb 2018
Deeply subducted continental fragments – Part 2: Insight from petrochronology in the central Sesia Zone (western Italian Alps)
Francesco Giuntoli
CORRESPONDING AUTHOR
Institute of Geological Sciences, University of Bern, Baltzerstrasse
1 + 3, 3012 Bern, Switzerland
Pierre Lanari
Institute of Geological Sciences, University of Bern, Baltzerstrasse
1 + 3, 3012 Bern, Switzerland
Marco Burn
Institute of Geological Sciences, University of Bern, Baltzerstrasse
1 + 3, 3012 Bern, Switzerland
Barbara Eva Kunz
Institute of Geological Sciences, University of Bern, Baltzerstrasse
1 + 3, 3012 Bern, Switzerland
Martin Engi
Institute of Geological Sciences, University of Bern, Baltzerstrasse
1 + 3, 3012 Bern, Switzerland
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Francesco Giuntoli, Pierre Lanari, and Martin Engi
Solid Earth, 9, 167–189, https://doi.org/10.5194/se-9-167-2018, https://doi.org/10.5194/se-9-167-2018, 2018
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Continental high-pressure terranes in orogens offer insight into deep recycling and transformation processes that occur in subduction zones. These remain poorly understood, and currently debated ideas need testing. We document complex garnet zoning in eclogitic mica schists from the Sesia Zone (western Italian Alps). These retain evidence of two orogenic cycles and provide detailed insight into resorption, growth, and diffusion processes induced by fluid pulses under high-pressure conditions.
Kilian Lecacheur, Olivier Fabbri, Francesca Piccoli, Pierre Lanari, Philippe Goncalves, and Henri Leclère
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In this study, we analyze a peculiar eclogite from the Western Alps, which not only recorded a classical subduction-to-exhumation path but revealed evidence of Ca-rich fluid–rock interaction. Chemical composition and modeling show that the rock experienced peak metamorphic conditions followed by Ca-rich pulsed fluid influx occurring consistently under high-pressure conditions. This research enhances our understanding of fluid–rock interactions in subduction settings.
Hugo Dominguez, Nicolas Riel, and Pierre Lanari
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Predicting the behaviour of magmatic systems is important for understanding Earth's matter and heat transport. Numerical modelling is a technique that can predict complex systems at different scales of space and time by solving equations using various techniques. This study tests four algorithms to find the best way to transport the melt composition. The "weighted essentially non-oscillatory" algorithm emerges as the best choice, minimising errors and preserving system mass well.
Julien Reynes, Jörg Hermann, Pierre Lanari, and Thomas Bovay
Eur. J. Mineral., 35, 679–701, https://doi.org/10.5194/ejm-35-679-2023, https://doi.org/10.5194/ejm-35-679-2023, 2023
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Garnet is a high-pressure mineral that may incorporate very small amounts of water in its structure (tens to hundreds of micrograms per gram H2O). In this study, we show, based on analysis and modelling, that it can transport up to several hundred micrograms per gram of H2O at depths over 80 km in a subduction zone. The analysis of garnet from the various rock types present in a subducted slab allowed us to estimate the contribution of garnet in the deep cycling of water in the earth.
Veronica Peverelli, Alfons Berger, Martin Wille, Thomas Pettke, Pierre Lanari, Igor Maria Villa, and Marco Herwegh
Solid Earth, 13, 1803–1821, https://doi.org/10.5194/se-13-1803-2022, https://doi.org/10.5194/se-13-1803-2022, 2022
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This work studies the interplay of epidote dissolution–precipitation and quartz dynamic recrystallization during viscous granular flow in a deforming epidote–quartz vein. Pb and Sr isotope data indicate that epidote dissolution–precipitation is mediated by internal/recycled fluids with an additional external fluid component. Microstructures and geochemical data show that the epidote material is redistributed and chemically homogenized within the deforming vein via a dynamic granular fluid pump.
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Geochronology, 3, 123–147, https://doi.org/10.5194/gchron-3-123-2021, https://doi.org/10.5194/gchron-3-123-2021, 2021
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This work presents LA-ICP-MS U–Pb geochronology of epidote in hydrothermal veins. The challenges of epidote dating are addressed, and a protocol is proposed allowing us to obtain epidote U–Pb ages with a precision as good as 5 % in addition to the initial Pb isotopic composition of the epidote-forming fluid. Epidote demonstrates its potential to be used as a U–Pb geochronometer and as a fluid tracer, allowing us to reconstruct the timing of hydrothermal activity and the origin of the fluid(s).
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Eur. J. Mineral., 32, 521–544, https://doi.org/10.5194/ejm-32-521-2020, https://doi.org/10.5194/ejm-32-521-2020, 2020
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We analysed apatite–allanite/epidote coronae around monazite and xenotime in deformed Permian pegmatites from the Austroalpine basement. Microscopy, chemical analysis and EBSD showed that these coronae formed by dissolution–precipitation processes during deformation of the host rocks. Dating of monazite and xenotime confirmed the magmatic origin of the corona cores, while LA-ICP-MS dating of allanite established a date of ~ 60 Ma for corona formation and deformation in the Austroalpine basement.
Alice Vho, Pierre Lanari, Daniela Rubatto, and Jörg Hermann
Solid Earth, 11, 307–328, https://doi.org/10.5194/se-11-307-2020, https://doi.org/10.5194/se-11-307-2020, 2020
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This study presents an approach that combines equilibrium thermodynamic modelling with oxygen isotope fractionation modelling for investigating fluid–rock interaction in metamorphic systems. An application to subduction zones shows that chemical and isotopic zoning in minerals can be used to determine feasible fluid sources and the conditions of interaction. Slab-derived fluids can cause oxygen isotope variations in the mantle wedge that may result in anomalous isotopic signatures of arc lavas.
Laura Stutenbecker, Peter M. E. Tollan, Andrea Madella, and Pierre Lanari
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The Aar and Mont Blanc regions in the Alps are large granitoid massifs characterized by high topography. We analyse when these granitoids were first exhumed to the surface. We test this by tracking specific garnet grains, which are exclusively found in the granitoid massifs, in the sediments contained in the alpine foreland basin. This research ties in with ongoing debates on the timing and mechanisms of mountain building.
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Solid Earth, 9, 167–189, https://doi.org/10.5194/se-9-167-2018, https://doi.org/10.5194/se-9-167-2018, 2018
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Continental high-pressure terranes in orogens offer insight into deep recycling and transformation processes that occur in subduction zones. These remain poorly understood, and currently debated ideas need testing. We document complex garnet zoning in eclogitic mica schists from the Sesia Zone (western Italian Alps). These retain evidence of two orogenic cycles and provide detailed insight into resorption, growth, and diffusion processes induced by fluid pulses under high-pressure conditions.
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Solid Earth Discuss., https://doi.org/10.5194/se-2020-95, https://doi.org/10.5194/se-2020-95, 2020
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Alice Vho, Pierre Lanari, Daniela Rubatto, and Jörg Hermann
Solid Earth, 11, 307–328, https://doi.org/10.5194/se-11-307-2020, https://doi.org/10.5194/se-11-307-2020, 2020
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Solid Earth, 11, 223–240, https://doi.org/10.5194/se-11-223-2020, https://doi.org/10.5194/se-11-223-2020, 2020
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Federico Lucci, Gerardo Carrasco-Núñez, Federico Rossetti, Thomas Theye, John Charles White, Stefano Urbani, Hossein Azizi, Yoshihiro Asahara, and Guido Giordano
Solid Earth, 11, 125–159, https://doi.org/10.5194/se-11-125-2020, https://doi.org/10.5194/se-11-125-2020, 2020
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Understanding the anatomy of active magmatic plumbing systems is essential to define the heat source(s) feeding geothermal fields. Mineral-melt thermobarometry and fractional crystallization (FC) models were applied to Quaternary volcanic products of the Los Humeros Caldera (Mexico). Results point to a magmatic system controlled by FC processes and made of magma transport and storage layers within the crust, with significant implications on structure and longevity of the geothermal reservoir.
Tomoaki Morishita, Naoto Hirano, Hirochika Sumino, Hiroshi Sato, Tomoyuki Shibata, Masako Yoshikawa, Shoji Arai, Rie Nauchi, and Akihiro Tamura
Solid Earth, 11, 23–36, https://doi.org/10.5194/se-11-23-2020, https://doi.org/10.5194/se-11-23-2020, 2020
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We report a peridotite xenolith-bearing basalt dredged from the Seifu Seamount (SSM basalt) in the northeast Tsushima Basin, southwest Sea of Japan, which is one of the western Pacific back-arc basin swarms. An 40Ar / 39Ar plateau age of 8.33 ± 0.15 Ma (2 σ) was obtained for the SSM basalt, indicating that it erupted shortly after the termination of back-arc spreading. The SSM basalt was formed in a post-back-arc extension setting by the low-degree partial melting of an upwelling asthenosphere.
Ariadni A. Georgatou and Massimo Chiaradia
Solid Earth, 11, 1–21, https://doi.org/10.5194/se-11-1-2020, https://doi.org/10.5194/se-11-1-2020, 2020
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We study the petrographical and geochemical occurrence of magmatic sulfide minerals in volcanic rocks for areas characterised by different geodynamic settings, some of which are associated with porphyry (Cu and/or Au) and Au epithermal mineralisation. The aim is to investigate the role of magmatic sulfide saturation processes in depth for ore generation in the surface.
Massimiliano Tirone
Solid Earth, 10, 1409–1428, https://doi.org/10.5194/se-10-1409-2019, https://doi.org/10.5194/se-10-1409-2019, 2019
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The prevalent assumption in solid Earth science is that if we have different lithologies in the mantle they are separately in chemical equilibrium and together in chemical disequilibrium; this is the condition that at the moment defines a chemically heterogeneous mantle. The main contribution of this study is to show that this may not be the case. We can have (partial) chemical equilibration between the two and still observe a chemically heterogeneous mantle.
Francesco Giuntoli, Pierre Lanari, and Martin Engi
Solid Earth, 9, 167–189, https://doi.org/10.5194/se-9-167-2018, https://doi.org/10.5194/se-9-167-2018, 2018
Short summary
Short summary
Continental high-pressure terranes in orogens offer insight into deep recycling and transformation processes that occur in subduction zones. These remain poorly understood, and currently debated ideas need testing. We document complex garnet zoning in eclogitic mica schists from the Sesia Zone (western Italian Alps). These retain evidence of two orogenic cycles and provide detailed insight into resorption, growth, and diffusion processes induced by fluid pulses under high-pressure conditions.
Elizaveta Kovaleva, Håkon O. Austrheim, and Urs S. Klötzli
Solid Earth, 8, 789–804, https://doi.org/10.5194/se-8-789-2017, https://doi.org/10.5194/se-8-789-2017, 2017
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This is a study of unusual coronae textures formed by zircon in granulitic metapelites, Ivrea–Verbano Zone (northern Italy). Zircon coronas occur in two generations: (1) thick (5–20 µm) crescent-shaped aggregates and (2) thin (≤ 1 µm) thread-shaped and tangled coronae. Both are found in the same petrological context, so that the difference between two generations is very conspicuous. Formation of zircon coronae is attributed to the two-stage decomposition of Fe–Ti oxides, a rich source of Zr.
Paula Ogilvie and Roger L. Gibson
Solid Earth, 8, 93–135, https://doi.org/10.5194/se-8-93-2017, https://doi.org/10.5194/se-8-93-2017, 2017
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Coronas are vital clues to the presence of arrested reaction in metamorphic rocks. We review formation mechanisms of coronas and approaches utilized to model their evolution in P–T–X space. Forward modelling employing calculated chemical potential gradients allows a far more nuanced understanding of the intricacies that govern metamorphic reaction. These models have critical implications for the limitations and opportunities coronas afford in interpreting the evolution of metamorphic terranes.
Faisal Khan, Frieder Enzmann, and Michael Kersten
Solid Earth, 7, 481–492, https://doi.org/10.5194/se-7-481-2016, https://doi.org/10.5194/se-7-481-2016, 2016
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X-ray microtomography image processing involves artefact reduction and image segmentation. The beam-hardening artefact is removed, applying a new algorithm, which minimizes the offsets of the attenuation data points. For the segmentation, we propose using a non-linear classifier algorithm. Statistical analysis was performed to quantify the improvement in multi-phase classification of rock cores using and without using our advanced beam-hardening correction algorithm.
Linda Luquot, Vanessa Hebert, and Olivier Rodriguez
Solid Earth, 7, 441–456, https://doi.org/10.5194/se-7-441-2016, https://doi.org/10.5194/se-7-441-2016, 2016
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To evaluate oil and gas production, accurate characterization (usually based on laboratory experiments) of reservoir rock properties needs to be performed. X-ray scanning samples enable obtaining 3-D images of the rock inner structure from which those properties can be obtained using images processing. This article shows that these two approaches are complementary and yield consistent results. Moreover, image-based calculations allow to save a huge amount of time compared to lab-based measures.
E. Berrezueta, B. Ordóñez-Casado, and L. Quintana
Solid Earth, 7, 37–53, https://doi.org/10.5194/se-7-37-2016, https://doi.org/10.5194/se-7-37-2016, 2016
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The aim of this article is to describe and interpret qualitative and quantitative changes at the rock matrix scale of Cretaceous sandstones (northern Spain) exposed to supercritical CO2 and brine. Experimental CO2-rich brine injection was performed in a reactor chamber under realistic conditions of deep saline formations (P ≈ 7.8 MPa, T ≈ 38 °C and 24 h exposure time). SEM and optical microscopy, aided by optical image processing and chemical analyses were used to study the rock samples.
S. Wiesmaier, D. Morgavi, C. J. Renggli, D. Perugini, C. P. De Campos, K.-U. Hess, W. Ertel-Ingrisch, Y. Lavallée, and D. B. Dingwell
Solid Earth, 6, 1007–1023, https://doi.org/10.5194/se-6-1007-2015, https://doi.org/10.5194/se-6-1007-2015, 2015
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We reproduced in an experiment the mixing of two different magmas by bubbles. Bubbles form filaments when dragging portions of one magma into another and thus mingle both magmas. Bubble mixing must be an accelerating process in nature, because formed filaments are channels of low resistance for subsequently rising bubbles. In natural gas-rich magmas, this may be an important mechanism for magma mixing. Natural samples from Axial Seamount show evidence for bubble mixing.
M. Ledevin, N. Arndt, A. Davaille, R. Ledevin, and A. Simionovici
Solid Earth, 6, 253–269, https://doi.org/10.5194/se-6-253-2015, https://doi.org/10.5194/se-6-253-2015, 2015
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We investigate the composition, physical and rheological properties of fluids at the origin of Palaeoarchean chert dikes in South Africa. The dikes formed by repetitive hydraulic fracturing as overpressured oceanic fluids were released at low temperatures as a siliceous slurry. The gelation capacity of silica conferred the chert precursor a viscoelastic, probably thixotrope behaviour. It is an additional step to understand fluid circulations towards the ocean floor, the habitat of early life.
K. Jamshidi, H. Ghasemi, V. R. Troll, M. Sadeghian, and B. Dahren
Solid Earth, 6, 49–72, https://doi.org/10.5194/se-6-49-2015, https://doi.org/10.5194/se-6-49-2015, 2015
I. V. Ashchepkov, N. V. Alymova, A. M. Logvinova, N. V. Vladykin, S. S. Kuligin, S. I. Mityukhin, H. Downes, Yu. B. Stegnitsky, S. A. Prokopiev, R. F. Salikhov, V. S. Palessky, and O. S. Khmel'nikova
Solid Earth, 5, 915–938, https://doi.org/10.5194/se-5-915-2014, https://doi.org/10.5194/se-5-915-2014, 2014
S. Bouquain, N. T. Arndt, F. Faure, and G. Libourel
Solid Earth, 5, 641–650, https://doi.org/10.5194/se-5-641-2014, https://doi.org/10.5194/se-5-641-2014, 2014
V. R. Troll, A. Klügel, M.-A. Longpré, S. Burchardt, F. M. Deegan, J. C. Carracedo, S. Wiesmaier, U. Kueppers, B. Dahren, L. S. Blythe, T. H. Hansteen, C. Freda, D. A. Budd, E. M. Jolis, E. Jonsson, F. C. Meade, C. Harris, S. E. Berg, L. Mancini, M. Polacci, and K. Pedroza
Solid Earth, 3, 97–110, https://doi.org/10.5194/se-3-97-2012, https://doi.org/10.5194/se-3-97-2012, 2012
M. Nasrabady, F. Rossetti, T. Theye, and G. Vignaroli
Solid Earth, 2, 219–243, https://doi.org/10.5194/se-2-219-2011, https://doi.org/10.5194/se-2-219-2011, 2011
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Short summary
Subducted continental terranes commonly comprise an assembly of subunits that reflect the different tectono-metamorphic histories they experienced in the subduction zone. Our challenge is to unravel how, when, and in which part of the subduction zone these subunits were juxtaposed. Our study documents when and in what conditions re-equilibration took place. Results constrain the main stages of mineral growth and deformation, associated with fluid influx that occurred in the subduction channel.
Subducted continental terranes commonly comprise an assembly of subunits that reflect the...
