Deciphering the magma storage conditions and preeruptive processes at Cumaçay: a Plio-Quaternary volcanic eruption center in Eastern Anatolia, Turkey

We investigate the geology and petrology of Cumaçay, one of the Plio-Quaternary eruption centers of post-collisional volcanism in Eastern Turkey, using a combination of geochronology, bulk-rock geochemistry, thermobarometry, and thermodynamic simulations. Our new K-Ar ages reveal an age of  3.5-0.97 Ma for the eruptive products, which spread around an area of ~1000 km². Mineral-melt equilibria for olivine, orthopyroxene, clinopyroxene, and plagioclase allow estimation of crystallization pressures, and temperatures indicate two separate crustal storage of crystallization at 14-28 km and 5-15 km. The temperature estimation from diverse methods ranges from 954 °C to 1224 °C. Thermodynamic modelings using Magma Chamber Simulator (MCS) at a representative pressure (5 Kbar) imply that the assimilation and crustal contamination (AFC) resulted in evolved melts with various SiO₂ contents at mid to lower crustal depths. Calculated wide range of temperatures, compositional variety from evolved members, and MCS recharge simulation at a representative pressure (2.5 Kbar) reveal that the magma mixing between contrasted melts characterize the final chemical dispersal of the erupted lavas.