Petrographical and petrological investigation the Alemdar and Isikdere plutons

In this study, petrographical, geochemical and petrological characteristics of the Alemdar and Işıkdere (Gümüşhane, NE Turkey) Plutons outcropping the limited area in the south of the Eastern Pontides were reported. These plutons extend nearly in the direction of NE-SW and intruded into the Early-Middle Carboniferous Gümüşhane Granitoid and Early-Middle Jurassic Şenköy Formation. Petrographically, the studied plutons are compositionally fine to medium grained quartz-diorite, quartz monzodiorite and tonalite. The studied plutons consist of plagioclase, quartz, K-feldspar, amphibole, biotite and Fe-Ti oxides with generally granular, poikilitic, graphics and rarely porphyric textures. Petrochemically, plutons represent I-type, high-K calc-alkaline affinities, metaluminous to peraluminous (A/CNK=0.86-1.13) and features of volcanic arc granitoid. The whole-rock major and trace element data indicate that fractional crystallization ± assimilation has performed a notable role in the evolution of the studied plutons. Primitive mantle-normalized trace element patterns of the rocks show enrichment in large ion lithophile elements (Sr, K, Rb, Ba), Th and Ce, and negative Ta, Nb and Ti anomalies suggesting subduction component in their petrogenesis. The chondrite normalized rare earth element (REE) patterns of the studied plutons display concave-shaped plots with negative Eu anomalies, all of which refer plagioclase ± amphibole fractionations. All evidence support that the magma of the plutons was formed by an enriched mantle wedge metasomatized by slab-derived fluids.