Deep origin of mantle peridotites from the Aladağ ophiolite, Turkey: Implication from trace element geochemistry of pyroxenes and mineralogy of ophiolitic diamonds

•Diamond and other exotic minerals have been recovered from the Aladag harzburgites.•The harzburgites have experienced partial melting initiated in the garnet stability field.•Deep processes involved in the formation of the Aladag mantle peridotites.•The dunites formed by intensive melt-rock interaction.