Fault rocks within the blueschist metabasalts of the Diamante-Terranova unit (southern Italy): potential fossil record of intermediate-depth subduction earthquakes
We report the first evidence of fault rocks developed during high-pressure/low temperature subduction-related metamorphism, within quartz+epidote pods embedded in the glaucophane-lawsonite-bearing ophiolitic metabasalts of the Diamante-Terranova unit (Calabria, Italy). Fault rocks occur as relic inj...
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Online Access: | http://hdl.handle.net/11588/747320 https://doi.org/10.1017/S0016756819000062 |
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ftunivnapoliiris:oai:www.iris.unina.it:11588/747320 2024-02-11T10:09:05+01:00 Fault rocks within the blueschist metabasalts of the Diamante-Terranova unit (southern Italy): potential fossil record of intermediate-depth subduction earthquakes Vitale, Stefano Fedele, Lorenzo Tramparulo, Francesco D'Assisi Prinzi, Ernesto Paolo Vitale, Stefano Fedele, Lorenzo Tramparulo, Francesco D'Assisi Prinzi, Ernesto Paolo 2019 http://hdl.handle.net/11588/747320 https://doi.org/10.1017/S0016756819000062 eng eng info:eu-repo/semantics/altIdentifier/wos/WOS:000488964700009 volume:156 firstpage:1771 lastpage:1782 numberofpages:12 journal:GEOLOGICAL MAGAZINE http://hdl.handle.net/11588/747320 doi:10.1017/S0016756819000062 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85063137844 fault rock pseudotachylyte ultracataclasite paleo-seismicity HP/LT metamorphism southern Apennines-Calabria-Peloritani Terrane info:eu-repo/semantics/article 2019 ftunivnapoliiris https://doi.org/10.1017/S0016756819000062 2024-01-16T23:32:04Z We report the first evidence of fault rocks developed during high-pressure/low temperature subduction-related metamorphism, within quartz+epidote pods embedded in the glaucophane-lawsonite-bearing ophiolitic metabasalts of the Diamante-Terranova unit (Calabria, Italy). Fault rocks occur as relic injections appearing as thin dark seams, locally showing an internal foliation characterized by tabular, curvilinear and meander-like shapes, and consist of very fine grains of glaucophane and titanite, locally including survivor clasts of epidote and lawsonite. Some boudinaged veins show glaucophane fibres in the boudin necks, marking a clear HP/LT syn-metamorphic origin at ca. 30 km depth. The injected fault rocks can be alternatively interpreted either as pseudotachylytes or as fluidized ultracataclasites. Although subsequent recrystallization largely obliterated primary diagnostic features, the occurrence of (i) different coloured flow streaks, characterized by alternating layers of glaucophane and titanite, (ii) well-developed flow-folds and (iii) corroded epidote survivor crystals, could indicate a viscous flow of molten material characterized by a non-uniform chemical composition. With this in mind, we support the hypothesis that these fine-grained veins were originally pseudotachylytes generated by the frictional melting of the glaucophane-rich layers of the Diamante-Terranova metabasalts, likely related with seismic events occurring during the Eocene along thrust faults within the subducting oceanic Ligurian lithosphere. The lack of evidence for pseudotachylyte relics in the metabasalt source rock argues for a selective preservation, largely dependent on the efficient mechanical shielding action of the stiffer quartz+epidote pods. Article in Journal/Newspaper Terranova IRIS Università degli Studi di Napoli Federico II Diamante ENVELOPE(-48.500,-48.500,-82.667,-82.667) Geological Magazine 156 10 1771 1782 |
institution |
Open Polar |
collection |
IRIS Università degli Studi di Napoli Federico II |
op_collection_id |
ftunivnapoliiris |
language |
English |
topic |
fault rock pseudotachylyte ultracataclasite paleo-seismicity HP/LT metamorphism southern Apennines-Calabria-Peloritani Terrane |
spellingShingle |
fault rock pseudotachylyte ultracataclasite paleo-seismicity HP/LT metamorphism southern Apennines-Calabria-Peloritani Terrane Vitale, Stefano Fedele, Lorenzo Tramparulo, Francesco D'Assisi Prinzi, Ernesto Paolo Fault rocks within the blueschist metabasalts of the Diamante-Terranova unit (southern Italy): potential fossil record of intermediate-depth subduction earthquakes |
topic_facet |
fault rock pseudotachylyte ultracataclasite paleo-seismicity HP/LT metamorphism southern Apennines-Calabria-Peloritani Terrane |
description |
We report the first evidence of fault rocks developed during high-pressure/low temperature subduction-related metamorphism, within quartz+epidote pods embedded in the glaucophane-lawsonite-bearing ophiolitic metabasalts of the Diamante-Terranova unit (Calabria, Italy). Fault rocks occur as relic injections appearing as thin dark seams, locally showing an internal foliation characterized by tabular, curvilinear and meander-like shapes, and consist of very fine grains of glaucophane and titanite, locally including survivor clasts of epidote and lawsonite. Some boudinaged veins show glaucophane fibres in the boudin necks, marking a clear HP/LT syn-metamorphic origin at ca. 30 km depth. The injected fault rocks can be alternatively interpreted either as pseudotachylytes or as fluidized ultracataclasites. Although subsequent recrystallization largely obliterated primary diagnostic features, the occurrence of (i) different coloured flow streaks, characterized by alternating layers of glaucophane and titanite, (ii) well-developed flow-folds and (iii) corroded epidote survivor crystals, could indicate a viscous flow of molten material characterized by a non-uniform chemical composition. With this in mind, we support the hypothesis that these fine-grained veins were originally pseudotachylytes generated by the frictional melting of the glaucophane-rich layers of the Diamante-Terranova metabasalts, likely related with seismic events occurring during the Eocene along thrust faults within the subducting oceanic Ligurian lithosphere. The lack of evidence for pseudotachylyte relics in the metabasalt source rock argues for a selective preservation, largely dependent on the efficient mechanical shielding action of the stiffer quartz+epidote pods. |
author2 |
Vitale, Stefano Fedele, Lorenzo Tramparulo, Francesco D'Assisi Prinzi, Ernesto Paolo |
format |
Article in Journal/Newspaper |
author |
Vitale, Stefano Fedele, Lorenzo Tramparulo, Francesco D'Assisi Prinzi, Ernesto Paolo |
author_facet |
Vitale, Stefano Fedele, Lorenzo Tramparulo, Francesco D'Assisi Prinzi, Ernesto Paolo |
author_sort |
Vitale, Stefano |
title |
Fault rocks within the blueschist metabasalts of the Diamante-Terranova unit (southern Italy): potential fossil record of intermediate-depth subduction earthquakes |
title_short |
Fault rocks within the blueschist metabasalts of the Diamante-Terranova unit (southern Italy): potential fossil record of intermediate-depth subduction earthquakes |
title_full |
Fault rocks within the blueschist metabasalts of the Diamante-Terranova unit (southern Italy): potential fossil record of intermediate-depth subduction earthquakes |
title_fullStr |
Fault rocks within the blueschist metabasalts of the Diamante-Terranova unit (southern Italy): potential fossil record of intermediate-depth subduction earthquakes |
title_full_unstemmed |
Fault rocks within the blueschist metabasalts of the Diamante-Terranova unit (southern Italy): potential fossil record of intermediate-depth subduction earthquakes |
title_sort |
fault rocks within the blueschist metabasalts of the diamante-terranova unit (southern italy): potential fossil record of intermediate-depth subduction earthquakes |
publishDate |
2019 |
url |
http://hdl.handle.net/11588/747320 https://doi.org/10.1017/S0016756819000062 |
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:000488964700009 volume:156 firstpage:1771 lastpage:1782 numberofpages:12 journal:GEOLOGICAL MAGAZINE http://hdl.handle.net/11588/747320 doi:10.1017/S0016756819000062 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85063137844 |
op_doi |
https://doi.org/10.1017/S0016756819000062 |
container_title |
Geological Magazine |
container_volume |
156 |
container_issue |
10 |
container_start_page |
1771 |
op_container_end_page |
1782 |
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1790608813712211968 |