Nascent subduction: record in Yukon eclogites
International audience Eclogites from the Faro area (Yukon-Tanana terrain, Canada) occur within glaucophane schists, mica gneisses, and quartzites. The rocks provide evidence of metamorphic evolution during the onset of subduction. Geothermobarometry (by the Grt-Cpx thermometer and the Cpx-Qtz-Pl ba...
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ftccsdartic:oai:HAL:hal-03867279v1 2023-05-15T16:10:07+02:00 Nascent subduction: record in Yukon eclogites Philippot, Pascal Perchuk, Alexei Laboratoire de Pétrologie, Modélisation de Matériaux et Processus (UMR 7160) Université Pierre et Marie Curie - Paris 6 (UPMC) Lomonosov Moscow State University (MSU) 2000-01 https://hal.archives-ouvertes.fr/hal-03867279 en eng HAL CCSD MAIK Nauka/Interperiodica hal-03867279 https://hal.archives-ouvertes.fr/hal-03867279 ISSN: 0869-5911 EISSN: 1556-2085 Petrology https://hal.archives-ouvertes.fr/hal-03867279 Petrology, 2000, 8, pp.1-18 [SDE]Environmental Sciences info:eu-repo/semantics/article Journal articles 2000 ftccsdartic 2022-11-27T07:44:47Z International audience Eclogites from the Faro area (Yukon-Tanana terrain, Canada) occur within glaucophane schists, mica gneisses, and quartzites. The rocks provide evidence of metamorphic evolution during the onset of subduction. Geothermobarometry (by the Grt-Cpx thermometer and the Cpx-Qtz-Pl barometer) points to an increase in the temperature and minimum pressure (from ∼520°C, 11 kbar to ∼690°C, 15 kbar) during the prograde stage. The retrograde stage occurred at an insignificant decompression and a temperature decrease to ∼540°C. The overall P-T metamorphic trajectory of the eclogites is counterclockwise. The Fe-Mn cores of garnet idioblasts bear small (no more than 50 μm in diameter) relics of Ca-rich garnet, which was contained in the rock prior to the prograde eclogite-facies metamorphism. The finding of the garnet relics made it possible to utilize geospeedometry to constrain the timing not only of the retrograde but also of the prograde stages. A simulation (based on the model for diffusion in a sphere) of the conditions under which the garnet relics could be preserved indicates that the total duration of the P-T metamorphic evolution of the eclogite did not exceed 0.2 Ma. The corresponding estimates for the minimum burial and heating rates are 7 cm/year and 850°C/Ma, respectively. The subsequent retrograde evolution of the eclogite proceeded with a minimum cooling rate as high as 750°C/Ma. According to the proposed thermal-tectonic model, the very rapid temperature and pressure changes in the eclogite were caused not only by the displacement of the rock but also by rapid transformations in the thermal structure of the subduction zone. Article in Journal/Newspaper Faro Yukon Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Canada Faro ENVELOPE(-133.353,-133.353,62.231,62.231) Yukon |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
[SDE]Environmental Sciences |
spellingShingle |
[SDE]Environmental Sciences Philippot, Pascal Perchuk, Alexei Nascent subduction: record in Yukon eclogites |
topic_facet |
[SDE]Environmental Sciences |
description |
International audience Eclogites from the Faro area (Yukon-Tanana terrain, Canada) occur within glaucophane schists, mica gneisses, and quartzites. The rocks provide evidence of metamorphic evolution during the onset of subduction. Geothermobarometry (by the Grt-Cpx thermometer and the Cpx-Qtz-Pl barometer) points to an increase in the temperature and minimum pressure (from ∼520°C, 11 kbar to ∼690°C, 15 kbar) during the prograde stage. The retrograde stage occurred at an insignificant decompression and a temperature decrease to ∼540°C. The overall P-T metamorphic trajectory of the eclogites is counterclockwise. The Fe-Mn cores of garnet idioblasts bear small (no more than 50 μm in diameter) relics of Ca-rich garnet, which was contained in the rock prior to the prograde eclogite-facies metamorphism. The finding of the garnet relics made it possible to utilize geospeedometry to constrain the timing not only of the retrograde but also of the prograde stages. A simulation (based on the model for diffusion in a sphere) of the conditions under which the garnet relics could be preserved indicates that the total duration of the P-T metamorphic evolution of the eclogite did not exceed 0.2 Ma. The corresponding estimates for the minimum burial and heating rates are 7 cm/year and 850°C/Ma, respectively. The subsequent retrograde evolution of the eclogite proceeded with a minimum cooling rate as high as 750°C/Ma. According to the proposed thermal-tectonic model, the very rapid temperature and pressure changes in the eclogite were caused not only by the displacement of the rock but also by rapid transformations in the thermal structure of the subduction zone. |
author2 |
Laboratoire de Pétrologie, Modélisation de Matériaux et Processus (UMR 7160) Université Pierre et Marie Curie - Paris 6 (UPMC) Lomonosov Moscow State University (MSU) |
format |
Article in Journal/Newspaper |
author |
Philippot, Pascal Perchuk, Alexei |
author_facet |
Philippot, Pascal Perchuk, Alexei |
author_sort |
Philippot, Pascal |
title |
Nascent subduction: record in Yukon eclogites |
title_short |
Nascent subduction: record in Yukon eclogites |
title_full |
Nascent subduction: record in Yukon eclogites |
title_fullStr |
Nascent subduction: record in Yukon eclogites |
title_full_unstemmed |
Nascent subduction: record in Yukon eclogites |
title_sort |
nascent subduction: record in yukon eclogites |
publisher |
HAL CCSD |
publishDate |
2000 |
url |
https://hal.archives-ouvertes.fr/hal-03867279 |
long_lat |
ENVELOPE(-133.353,-133.353,62.231,62.231) |
geographic |
Canada Faro Yukon |
geographic_facet |
Canada Faro Yukon |
genre |
Faro Yukon |
genre_facet |
Faro Yukon |
op_source |
ISSN: 0869-5911 EISSN: 1556-2085 Petrology https://hal.archives-ouvertes.fr/hal-03867279 Petrology, 2000, 8, pp.1-18 |
op_relation |
hal-03867279 https://hal.archives-ouvertes.fr/hal-03867279 |
_version_ |
1765995359783354368 |