Concordant pulse in Mn, Y and HREEs concentrations during UHP eclogitic garnet growth: Transient rock dynamics along a cold subduction plate interface - Archive ouverte HAL Access content directly
Journal Articles Earth and Planetary Science Letters Year : 2020

Concordant pulse in Mn, Y and HREEs concentrations during UHP eclogitic garnet growth: Transient rock dynamics along a cold subduction plate interface

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1
Zhou Tan
  • Function : Author
Jun Gao
  • Function : Author
Tao Hong
Bo Wan
  • Function : Author

Abstract

We herein report strikingly concordant Mn, Y, and HREE garnet zoning in ultrahigh-pressure low-temperature oceanic eclogites found in the fossil Devonian-Carboniferous subduction plate interface in SW-Tianshan. Zr-in-rutile thermometry, thermodynamic modeling and diffusion-controlled garnet growth modeling show that this type of zoning can be explained by a short-lived transient, most likely a ∼80 °C thermal pulse (from 490 to 570 °C). This event could be as transient as ∼300 Ka, assuming a prograde to peak burial duration of 5 Ma. Such garnet zoning is observed for grains sampled meters apart (Fig. 1d) and was detected in other eclogites in the region. This transient event could reflect the short-lived movement of UHP oceanic slices, once detached, towards the hotter mantle wedge, and/or deformation-induced remobilization of fluids enhancing diffusion-controlled garnet growth.
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insu-03594508 , version 1 (02-03-2022)

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Zhou Tan, Philippe Agard, Jun Gao, Tao Hong, Bo Wan. Concordant pulse in Mn, Y and HREEs concentrations during UHP eclogitic garnet growth: Transient rock dynamics along a cold subduction plate interface. Earth and Planetary Science Letters, 2020, 530, p.501-507. ⟨10.1016/j.epsl.2019.115908⟩. ⟨insu-03594508⟩
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