Origin of Fe-rich lherzolites and wehrlites from Tok,SE Siberia by reactive melt percolation in refractory mantle peridotites |
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| Authors: | Email author" target="_blank">Dmitri?A?IonovEmail author Ingrid?Chanefo Jean-Louis?Bodinier |
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| Institution: | (1) Abteilung Geochemie, Max-Planck-Institut für Chemie, Postfach 3060, 55020 Mainz, Germany;(2) Laboratoire de Tectonophysique, UMR 5568 CNRS, ISTEEM, Université Montpellier 2, case 049, 34095 Montpellier, Cedex 05, France |
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| Abstract: | Lherzolite–wehrlite (LW) series xenoliths from the quaternary Tok volcanic field in the southeastern Siberian craton are distinguished
from the more common lherzolite–harzburgite (LH) series by (a) low Mg numbers (0.84–0.89) at high modal olivine (66–84%) and
(b) widespread replacement of orthopyroxene (0–12%) and spinel by clinopyroxene (7–22%). The LW series peridotites are typically
enriched in Ca, Fe, Mn and Ti, and depleted in Si, Ni and Cr relative to refractory LH series rocks (Mg number ≥0.89), which
are metasomatised partial melting residues. Numerical modelling of Fe–Mg solid/liquid exchange during melt percolation demonstrates
that LW series rocks can form by reaction of host refractory peridotites with evolved (Mg numbers 0.6–0.7), silica-undersaturated
silicate melts at high melt/rock ratios, which replace orthopyroxene with clinopyroxene and decrease Mg numbers. This process
is most likely related to underplating and fractionation of basaltic magma in the shallow mantle, which also produced olivine–clinopyroxene
cumulates found among the Tok xenoliths. |
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| Keywords: | Siberia Lithospheric mantle Peridotite Wehrlite Reactive melt percolation |
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