Mineralogy, petrography and whole-rock geochemistry of the Tertiary granitic intrusions in the Eastern Pontides, Turkey

摘要: Abstract Granitic intrusions in Eocene and post-Eocene volcanic rocks outcrop the Northern Southern Zones of Eastern Pontides, NE Turkey. Intrusions Zone extend NW–SE whereas those are nearly E–W orientated. The contacts with sharp, epidotized include xenoliths. margins often contain abundant angular mafic microgranular enclaves diorite to quartz composition. also show evidence mingling mixing between coeval felsic magmas. Field observations suggest a stopping type ascent emplacement style for intrusions. Petrographically, variations both colour mineralogy fine medium granular, monzonitic, poikilitic, rapakivi, anti-rapakivi graphic textures. Based on modal mineralogy, monzonite, monzodiorite samples monzogranite granodiorite. generally calc-alkaline mildly alkaline transitional metaluminous, CAFEMIC trend. form post-collisional, A-type, monzonitic association I-type, granodioritic calc-alkaline-transitional association. Whole-rock compositional data indicate that differentiation occurred via fractional crystallisation or without magma mixing. Incompatible rare earth element patterns were derived from melting mantle region enriched by subduction-related fluids but evolved differently during emplacement. U–Pb zircon dating yields an intrusion age 44.4±0.3 Ma. Regional geodynamics indicates post-collisional extensional tectonics region. Crustal involvement level may have been important magmatic evolution, especially intrusions, after cessation subduction subsequent crustal thickening.