Petrogenesis of arc-related serpentinized peridotites (Egypt): Insights into Neoproterozoic mantle evolution beneath the Arabian-Nubian Shield

•Two ophiolitic peridotites in the SE Desert of Egypt provide a window into the Neoproterzoic mantle.•Geochemistry of peridotite and its mineral chemistry suggest an origin in the arc-related setting.•SED peridotites are refractory mantle residues (25–40% melting), like modern fore-arc peridotites.•Geochemical aspects of peridotite indicate changing from extension during subduction initiation.