Akademik Veri Yönetim Sistemi
Gumushane Universitesi Fen Bilimleri Dergisi, cilt.15, sa.1, ss.140-160, 2025 (Scopus)
In this study the formation conditions and petrogenetic characteristics of orthopyroxenites in the mantle section of the Kırdağ ophiolite (Erzurum, NE Turkey), which outcrops within the Erzurum-Kars Ophiolite Zone in the Eastern Pontides, have been evaluated for the first time using mineral chemistry and whole-rock geochemical data. The main mineralogical composition of the samples taken from the orthopyroxenites consists predominantly of orthopyroxenes, with lesser amounts of clinopyroxenes and subhedral to euhedral chromian spinels. The mineral compositions, characterized by partially high Cr# and low TiO2 contents in chromian spinels, and high Mg# and low Al2O3 contents in pyroxenes, indicate that the formation conditions involve the re-melting of a depleted mantle source. Additionally, high whole-rock Mg# values, concave-shaped rare earth element (REE) patterns, and enrichment in large-ion lithophile elements (LILE) explain metasomatic events during melt-peridotite interaction processes in the subduction zone. As a result, it is understood that the petrographic and petrological characteristics of the studied orthopyroxenites indicate that they formed through the transformation of olivines into orthopyroxenes via the reaction of the parent peridotite with highsilica melts in a subduction zone.