Rates of thermal equilibration at the onset of subduction deduced from diffusion modeling of eclogitic garnets, Yukon-Tanana terrane, Canada

International audience Well-preserved eclogitic rocks near Faro (Yukon-Tanana terrane, Canada) underwent a prograde evolution from ∼510 °C and ≥ 1.1 GPa to 690 °C and ≥ 1.5 Gpa followed by near-isobaric cooling to ∼540 °C. A remarkable feature of the garnet porphyroblast cores is the presence of min...

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Bibliographic Details
Main Authors: Philippot, Pascal, Perchuk, Alexei, Erdmer, Philippe, Fialin, Michel
Other Authors: Laboratoire Pétrologie, Université Pierre et Marie Curie - Paris 6 (UPMC), Russian Academy of Sciences Moscow (RAS), University of Alberta, Plateforme Camparis - Plateforme analytique MEN (Microanalyses en sciences de l’Environnement) Paris, Observatoire des sciences de l'univers Ecce Terra Paris (ECCE TERRA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 1999
Subjects:
[SDE]Environmental Sciences
Canada
Faro
Yukon
Online Access:https://hal.archives-ouvertes.fr/hal-03865852
https://doi.org/10.1130/0091-7613(1999)027<0531:ROTEAT>2.3.CO;2
Description
Summary:International audience Well-preserved eclogitic rocks near Faro (Yukon-Tanana terrane, Canada) underwent a prograde evolution from ∼510 °C and ≥ 1.1 GPa to 690 °C and ≥ 1.5 Gpa followed by near-isobaric cooling to ∼540 °C. A remarkable feature of the garnet porphyroblast cores is the presence of minute garnet “inclusions” of distinctly different composition. Preservation of a sharp compositional gradient at the interface between the host and the inclusion garnets and results of diffusion modeling indicate that the counterclockwise pressure-time evolution took place on a very short time scale of about 0.2 m.y. Minimum rates of heating (950 °C/m.y.) and burial (7 cm/yr) calculated along the prograde part of the path are in good agreement with values extracted from thermal models of newly initiated subduction zones.

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