Petrographical, Geochemical and Perological Characteristics of Late Cretaceous aged Bozat (Giresun, NE Turkey) Pluton

Late Cretaceous aged intrusions in the Eastern Pontides Orogenic Belt in NE Turkey are common in varying sizes and compositions. Of these, Bozat Pluton (Giresun) extends nearly in the orientation of NE-SW and was emplaced into the Upper Cretaceous volcanic and sedimentary rocks. Petrographically, the studied pluton is compositionally fine to medium grained monzogabbro. The rocks of the pluton consist of plagioclase (An53-88), orthoclase (Or59-74), quartz, clinopyroxene (Wo40-45En42-44Fs12-17), biotite (Mg#: 0.66-0.70), Fe-Ti oxide, apatite and zircon with generally monzonitic, poikilitic, rare perthitic textures. Petrochemically, the studied pluton shows I-type, metaluminous (A/CNK=0.76-0.93) and shoshonitic features. The major and trace element data suggest that fractionational crystallization ± assimilation has played a significant role in the evolution of the studied pluton. Primitive mantle-normalized trace element patterns of rocks samples from the pluton exhibit enrichment in large ion lithophile element, Th, Ce and negative Nb, Ta and Ti anomalies, all of which suggest subduction component in their petrogenesis. Moreover, chondrite-normalized rare earth element (REE) plots of rocks from the pluton show characteristic concave-shaped patterns with negative Eu anomalies, all of which imply significant K-feldspar ± plagioclase and clinopyroxene fractionations in evolution of the pluton. All obtained data suggest that the Late Cretaceous aged Bozat Pluton has formed in an extensional continental arc, and parental magma of the pluton evolved from mixing of lithospheric mantle and lower crust-derived melts, and evolved differently within crustal level