Seismic properties of the supra-subduction mantle: Constraints from peridotite xenoliths from the Avacha volcano, southern Kamchatka

This work presents seismic properties derived from a detailed microstructural study of supra-subduction mantle xenoliths extracted by the active Avacha volcano in the southern Kamchatka arc. These peridotites underwent low-stress deformation and syn- to late-kinematic reactive percolation of hydrous...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: SOUSTELLE, Vincent, TOMMASI, Andrea
Format: Other/Unknown Material
Language:English
Published: American Geophysical Union 2010
Subjects:
seismic properties
xenolith
subduction
Planète et Univers [physics]/Sciences de la Terre/Tectonique
Sciences de l'environnement/Milieux et Changements globaux
Avacha
Kamchatka
Online Access:https://oskar-bordeaux.fr/handle/20.500.12278/35407
https://doi.org/10.1029/2010GL043450
Description
Summary:This work presents seismic properties derived from a detailed microstructural study of supra-subduction mantle xenoliths extracted by the active Avacha volcano in the southern Kamchatka arc. These peridotites underwent low-stress deformation and syn- to late-kinematic reactive percolation of hydrous melts or fluids leading to local orthopyroxene enrichment and dispersion of the olivine CPO in the shallow mantle wedge. All samples show an axial [ 100] olivine CPO implying fast S-wave polarization parallel to the flow direction in the mantle. Orthopyroxene-enrichment by reactive fluids/melts percolation lowers the Vp/Vs ratio, but cannot explain the Vp/Vs ratios <1.7 mapped in the Japan and Andes forearc mantle. These low Vp/Vs ratios may however be explained by considering the intrinsic anisotropy of the peridotites.

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