Field, Petrographic and Geochemical Characteristics of the Hamit Alkaline Intrusion in the Central Anatolian Crystalline Complex, Turkey

Authors: NURDANE İLBEYLİ

Abstract: The Hamit pluton is one of the alkaline intrusions in the Central Anatolian Crystalline Complex (CACC). The pluton consists of nepheline syenite, pseudoleucite syenite, alkali-feldspar syenite and quartz syenite. The nepheline syenite and pseudoleucite syenite are cut by foid-bearing microsyenitic dykes, whereas the alkali-feldspar syenite and quartz syenite are cut by aplitic and silicic dykes. The predominantly peralkaline Hamit intrusive rocks possess field, petrographic and geochemical characteristics comparable to A-type granites. All intrusive rocks of this pluton show enrichment in LILE and LREE relative to HFSE. The Th/Yb versus Ta/Yb plot suggests that the intrusive rocks formed from an enriched mantle source region carrying a subduction component inherited from pre-collision subduction events. Either thermal perturbation of the metasomatised lithosphere by delamination of the thermal boundary layer (TBL) or removal of a subducted plate (slab breakoff) are the likely mechanisms for initiation of the post-collisional magmatism of this complex.

Keywords: Hamit pluton, Central Anatolian Crystalline Complex (CACC), syenite, A-type granites, post-collisional intrusives

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