Cold subduction zone in northern Calabria (Italy) revealed by lawsonite–clinopyroxene blueschists
Abstract Lawsonite blueschists are important markers of cold subduction zones, subjected to intense fluid circulation. This is because lawsonite preservation in exhumed blueschists and eclogites is typically linked to cold exhumation paths, accompanied by hydration. In the Catena Costiera (Calabria,...
Published in: | Journal of Metamorphic Geology |
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crwiley:10.1111/jmg.12528 2024-06-23T07:57:09+00:00 Cold subduction zone in northern Calabria (Italy) revealed by lawsonite–clinopyroxene blueschists Tursi, Fabrizio Bianco, Caterina Brogi, Andrea Caggianelli, Alfredo Prosser, Giacomo Ruggieri, Giovanni Braschi, Eleonora Universita degli Studi di Bari Aldo Moro 2020 http://dx.doi.org/10.1111/jmg.12528 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjmg.12528 https://onlinelibrary.wiley.com/doi/pdf/10.1111/jmg.12528 https://onlinelibrary.wiley.com/doi/full-xml/10.1111/jmg.12528 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Journal of Metamorphic Geology volume 38, issue 5, page 451-469 ISSN 0263-4929 1525-1314 journal-article 2020 crwiley https://doi.org/10.1111/jmg.12528 2024-06-13T04:25:44Z Abstract Lawsonite blueschists are important markers of cold subduction zones, subjected to intense fluid circulation. This is because lawsonite preservation in exhumed blueschists and eclogites is typically linked to cold exhumation paths, accompanied by hydration. In the Catena Costiera (Calabria, southern Italy), lawsonite–clinopyroxene blueschists of the Diamante–Terranova Unit, affected by ductile shearing and retrogression, are exposed. Blueschists contain zoned clinopyroxene crystals, showing core–rim compositional variation from diopside to omphacite and hosting primary inclusions of lawsonite and titanite. Thermodynamic modelling of phase equilibria in the NCKFMASHTO system revealed peak metamorphic conditions of 2.0–2.1 GPa and 475–490°C for the Alpine subduction in Calabria. The subsequent post‐peak metamorphic evolution mainly proceeded along a decompression and cooling path up to ~1.1 GPa and ~380°C. The final exhumation stages are recorded in the sheared blueschists where a mylonitic to ultramylonitic foliation developed at ~0.7 GPa and 290–315°C. Therefore, the P–T evolution of the Diamante–Terranova blueschists mostly occurred in the stability field of lawsonite, sustained by H 2 O‐saturated conditions during the exhumation path. The results of this study indicate that the blueschists underwent peak metamorphic conditions higher than previously thought, reaching a maximum depth of ~70 km under a very cold geothermal gradient (~6.6°C/km), during the Eocene subduction of the Ligurian Tethys oceanic crust in Calabria. Article in Journal/Newspaper Terranova Wiley Online Library Diamante ENVELOPE(-48.500,-48.500,-82.667,-82.667) Journal of Metamorphic Geology 38 5 451 469 |
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Open Polar |
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Wiley Online Library |
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crwiley |
language |
English |
description |
Abstract Lawsonite blueschists are important markers of cold subduction zones, subjected to intense fluid circulation. This is because lawsonite preservation in exhumed blueschists and eclogites is typically linked to cold exhumation paths, accompanied by hydration. In the Catena Costiera (Calabria, southern Italy), lawsonite–clinopyroxene blueschists of the Diamante–Terranova Unit, affected by ductile shearing and retrogression, are exposed. Blueschists contain zoned clinopyroxene crystals, showing core–rim compositional variation from diopside to omphacite and hosting primary inclusions of lawsonite and titanite. Thermodynamic modelling of phase equilibria in the NCKFMASHTO system revealed peak metamorphic conditions of 2.0–2.1 GPa and 475–490°C for the Alpine subduction in Calabria. The subsequent post‐peak metamorphic evolution mainly proceeded along a decompression and cooling path up to ~1.1 GPa and ~380°C. The final exhumation stages are recorded in the sheared blueschists where a mylonitic to ultramylonitic foliation developed at ~0.7 GPa and 290–315°C. Therefore, the P–T evolution of the Diamante–Terranova blueschists mostly occurred in the stability field of lawsonite, sustained by H 2 O‐saturated conditions during the exhumation path. The results of this study indicate that the blueschists underwent peak metamorphic conditions higher than previously thought, reaching a maximum depth of ~70 km under a very cold geothermal gradient (~6.6°C/km), during the Eocene subduction of the Ligurian Tethys oceanic crust in Calabria. |
author2 |
Universita degli Studi di Bari Aldo Moro |
format |
Article in Journal/Newspaper |
author |
Tursi, Fabrizio Bianco, Caterina Brogi, Andrea Caggianelli, Alfredo Prosser, Giacomo Ruggieri, Giovanni Braschi, Eleonora |
spellingShingle |
Tursi, Fabrizio Bianco, Caterina Brogi, Andrea Caggianelli, Alfredo Prosser, Giacomo Ruggieri, Giovanni Braschi, Eleonora Cold subduction zone in northern Calabria (Italy) revealed by lawsonite–clinopyroxene blueschists |
author_facet |
Tursi, Fabrizio Bianco, Caterina Brogi, Andrea Caggianelli, Alfredo Prosser, Giacomo Ruggieri, Giovanni Braschi, Eleonora |
author_sort |
Tursi, Fabrizio |
title |
Cold subduction zone in northern Calabria (Italy) revealed by lawsonite–clinopyroxene blueschists |
title_short |
Cold subduction zone in northern Calabria (Italy) revealed by lawsonite–clinopyroxene blueschists |
title_full |
Cold subduction zone in northern Calabria (Italy) revealed by lawsonite–clinopyroxene blueschists |
title_fullStr |
Cold subduction zone in northern Calabria (Italy) revealed by lawsonite–clinopyroxene blueschists |
title_full_unstemmed |
Cold subduction zone in northern Calabria (Italy) revealed by lawsonite–clinopyroxene blueschists |
title_sort |
cold subduction zone in northern calabria (italy) revealed by lawsonite–clinopyroxene blueschists |
publisher |
Wiley |
publishDate |
2020 |
url |
http://dx.doi.org/10.1111/jmg.12528 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjmg.12528 https://onlinelibrary.wiley.com/doi/pdf/10.1111/jmg.12528 https://onlinelibrary.wiley.com/doi/full-xml/10.1111/jmg.12528 |
long_lat |
ENVELOPE(-48.500,-48.500,-82.667,-82.667) |
geographic |
Diamante |
geographic_facet |
Diamante |
genre |
Terranova |
genre_facet |
Terranova |
op_source |
Journal of Metamorphic Geology volume 38, issue 5, page 451-469 ISSN 0263-4929 1525-1314 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/jmg.12528 |
container_title |
Journal of Metamorphic Geology |
container_volume |
38 |
container_issue |
5 |
container_start_page |
451 |
op_container_end_page |
469 |
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1802650623560122368 |