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A new mantle xenolith locality from Simien shield volcano, NW Ethiopia

Published online by Cambridge University Press:  06 November 2008

DEREJE AYALEW ,
NICK ARNDT ,
FLORENCE BASTIEN ,
GEZAHEGN YIRGU  and
BRUNO KIEFFER
DEREJE AYALEW*
Affiliation:
Department of Earth Sciences, Addis Ababa University, P.O. Box 729/1033, Addis Ababa, Ethiopia
NICK ARNDT
Affiliation:
Laboratoire de Géodynamique des Chaînes Alpines, UMR 5025 CNRS, BP 53, 38041 Grenoble Cedex, France
FLORENCE BASTIEN
Affiliation:
Laboratoire de Géodynamique des Chaînes Alpines, UMR 5025 CNRS, BP 53, 38041 Grenoble Cedex, France
GEZAHEGN YIRGU
Affiliation:
Department of Earth Sciences, Addis Ababa University, P.O. Box 729/1033, Addis Ababa, Ethiopia
BRUNO KIEFFER
Affiliation:
Department of Earth and Ocean Sciences, University of British Columbia, Vancouver, BC, Canada
*
†Author for correspondence: [email protected], [email protected]
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Abstract

Thin-section observations and electron probe analyses, and trace element data are reported from a new mantle xenolith hosted in Miocene alkali basalt from the western flank of Simien shield volcano, Ethiopia. The spinel lherzolite enclaves contain variable proportions of olivine, orthopyroxene, green clinopyroxene and brown spinel, and have undergone deformation and partial recrystallization. They represent unmetasomatized, fertile xenoliths which were subjected to a late-stage melt–rock reaction. Trace element contents of clinopyroxene crystals are extremely low and quite different from those of the other xenoliths within the East African Rift System.

Keywords

lithospheric mantleSimienspinel lherzolitesxenolith
Type
Original Article
Information
Geological Magazine , Volume 146 , Issue 1 , January 2009 , pp. 144 - 149
Copyright
Copyright © Cambridge University Press 2008

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