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Magnesian andesites from the island of Skyros, Greece: geochemistry and regional significance

Published online by Cambridge University Press:  01 May 2009

G. Pe-Piper
Affiliation:
Department of Geology, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada

Abstract

High-magnesian andesites outcrop in a subvolcanic complex in the island of Skyros in the central Aegean Sea. Mineralogical indicators of this high-Mg content include bronzite and clinopyroxene phenocrysts, the former with high Cr2O3, and some phlogopite. Plagioclase (oligoclase–andesine) and Fe–Ti oxides were late phases to appear at the liquidus. Whole-rock geochemistry shows trace element features similar to those of subduction-related rocks. Radiometric dating indicates an early Serravallian (middle Miocene) age, approximately synchronous with the onset of post-orogenic rifting and extension of the Aegean Sea. This tectonic setting is consistent with an origin by adiabatic decompression of mantle peridotite previously modified by subduction-related fluids.

Type
Articles
Copyright
Copyright © Cambridge University Press 1991

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