Decoding a post-collisional multistage magma system: The Quaternary ignimbrites of Aragats stratovolcano, western Armenia

Tracking the p-T paths of cumulate fragments (pyroxene, plagioclase) in the younger units, we estimate the depth of the anhydrous crystal-rich magmatic chamber at around 25 km. Based on the composition of clinopyroxene cumulates, we propose a multi-stage evolution of melts from subalkaline and tholeiitic to calc-alkaline composition. The pronounced high Zr content and Zr/Hf ratios of the entire Upper Pliocene to Quaternary post-collisional magmatism could be attributed to partial melting of an enriched mantle source in the Lesser Caucasus.