lamproites as indicators of accretion and/or shallow subduction in the assembly of South-Western Anatolia, Turkey

The geochemistry and mineralogy of lamproites from south-western Anatolia can be used as a snapshot of the lithospheric composition beneath the Menderes Massif. High and near-constant K₂O contents, the presence of mantle xenocrystic phlogopite and olivine, highly magnesian olivine phenocrysts and Cr-rich spinel inclusions all indicate that the lithospheric mantle was phlogopite-bearing ultradepleted harzburgite at the time of lamproite eruption (20-4 Ma). This mantle assemblage most probably originated in a complex multistage process, including (intra-oceanic) supra-subduction zone depletion during the final stages of southern Neotethyan ocean closure, and accretion of the forearc oceanic lithosphere as shallowly subducted material to the already assembled Anatolia. The data presented here support shallow subduction of the oceanic lithosphere as a cause of the uplift of the Menderes Massif, in contrast to the traditional core-complex model.Terra Nova, 00, 000-000, 2010.