Cold subduction zone in northern Calabria (Italy) revealed by lawsonite–clinopyroxene blueschists
Lawsonite blueschists are important markers of cold subduction zones, subjected to intense fluid circulation. This is because lawsonite preservation in exhumed blues- chists and eclogites is typically linked to cold exhumation paths, accompanied by hy- dration. In the Catena Costiera (Calabria, sout...
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ftunivbari:oai:ricerca.uniba.it:11586/263633 2023-05-15T18:31:38+02:00 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 2020 http://hdl.handle.net/11586/263633 https://doi.org/10.1111/jmg.12528 eng eng info:eu-repo/semantics/altIdentifier/wos/WOS:000541173200001 volume:38 issue:5 firstpage:451 lastpage:469 numberofpages:19 journal:JOURNAL OF METAMORPHIC GEOLOGY http://hdl.handle.net/11586/263633 doi:10.1111/jmg.12528 2-s2.0-85082967556 https://doi.org/10.1111/jmg.12528 info:eu-repo/semantics/article 2020 ftunivbari https://doi.org/10.1111/jmg.12528 2022-09-25T20:40:32Z Lawsonite blueschists are important markers of cold subduction zones, subjected to intense fluid circulation. This is because lawsonite preservation in exhumed blues- chists and eclogites is typically linked to cold exhumation paths, accompanied by hy- dration. In the Catena Costiera (Calabria, southern Italy), lawsonite–clinopyroxene blueschists of the Diamante–Terranova Unit, affected by ductile shearing and retro- gression, 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 H2O-saturated condi- tions 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), dur- ing the Eocene subduction of the Ligurian Tethys oceanic crust in Calabria. Article in Journal/Newspaper Terranova Università degli Studi di Bari Aldo Moro: CINECA IRIS 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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Università degli Studi di Bari Aldo Moro: CINECA IRIS |
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ftunivbari |
language |
English |
description |
Lawsonite blueschists are important markers of cold subduction zones, subjected to intense fluid circulation. This is because lawsonite preservation in exhumed blues- chists and eclogites is typically linked to cold exhumation paths, accompanied by hy- dration. In the Catena Costiera (Calabria, southern Italy), lawsonite–clinopyroxene blueschists of the Diamante–Terranova Unit, affected by ductile shearing and retro- gression, 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 H2O-saturated condi- tions 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), dur- ing the Eocene subduction of the Ligurian Tethys oceanic crust in Calabria. |
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 |
publishDate |
2020 |
url |
http://hdl.handle.net/11586/263633 https://doi.org/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_relation |
info:eu-repo/semantics/altIdentifier/wos/WOS:000541173200001 volume:38 issue:5 firstpage:451 lastpage:469 numberofpages:19 journal:JOURNAL OF METAMORPHIC GEOLOGY http://hdl.handle.net/11586/263633 doi:10.1111/jmg.12528 2-s2.0-85082967556 https://doi.org/10.1111/jmg.12528 |
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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