P-T evolution of subophiolitic amphibolites beneath the Kınık Ophiolite (İAESZ, Türkiye): Insights from garnet and amphibole chemistry

The metamorphic sole rocks at the base of the Kınık Ophiolite in the İzmir-Ankara-Erzincan Suture Zone provide important insights into the tectonothermal evolution of the northern Neotethys. Field and petrographic observations reveal a sequence of amphibolites, garnet-amphibolites, amphibole schists, and quartz schists, displaying granoblastic to nematoblastic textures with retrograde overprinting by chlorite and epidote. Mineral chemical data show that garnets are dominated by almandine with subordinate pyrope and grossular, and very low spessartine, consistent with basaltic protoliths. Amphiboles are mainly calcic types, such as magnesiohornblende and tschermakite, preserving magmatic affinities but partly modified during metamorphism. Geothermobarometric calculations indicate peak conditions of ~640-790 °C and ~4-5 kbar, corresponding to medium- to upper-amphibolite facies at mid-crustal depths of ~14-20 km. The higher temperatures recorded in one sample suggest a low-pressure/high-temperature regime, typical of metamorphic soles. These findings demonstrate that the Kınık amphibolites originated from basaltic precursors and underwent LP-HT metamorphism during intra-oceanic subduction and subsequent ophiolite emplacement.