Investigation of petrographic, geochemical and petrological characteristics of adakite-like porphyrs located in Torul (Gümüşhane) and its surroundings

This thesis examines the petrography and whole-rock major and trace element geochemistry and petrology of Middle Eocene adakitic rocks located in the Mescitli region of the southern zone of the Eastern Pontides, and attempts to determine the origin and development of the magma that formed these rocks. The studied adakitic rocks have a porphyritic texture and are generally composed of andesite, and to a lesser extent trachy-andesite and dacite. The main minerals consist of plagioclase, quartz, alkali-feldspar, amphibole, biotite, and Fe-Ti oxide. The studied rocks exhibit adakitic geochemistry showing moderate-to-high potassium (1.1-3.6), high LaN/YbN (8.3–11.98) and Sr/Y (34-63) ratios. It was determined that the rocks are enriched in LREE, exhibit a nearly horizontal pattern in HREE (LaN/LuN = 7.8-11.8), and show no significant Eu anomaly (EuN/Eu* = 0.91-0.98). When all the obtained geochemical data are evaluated together, it can be said that these adakitic rocks may have originated from mafic lower crustal melts as a result of delamination mechanisms and developed as a result of possible interactions with lithospheric mantle components in the post-collisional tectonic regime of the Middle Eocene.