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...
Main Authors: | , , , |
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Other Authors: | , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
1999
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Subjects: | |
Online Access: | https://hal.archives-ouvertes.fr/hal-03865852 https://doi.org/10.1130/0091-7613(1999)027<0531:ROTEAT>2.3.CO;2 |
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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