Melt and fluid evolution in an upper-crustal magma reservoir, preserved by inclusions in juvenile clasts from the Kos Plateau Tuff, Aegean Arc, Greece

•Fluid inclusions from juvenile clasts record pre-eruptive pressure variations in the magma reservoir.•Most metals get enriched in the exsolving single-phase fluid compared to the rhyolitic melt.•Rapidly erupted fluid inclusions escaped post-entrapment modifications seen in slowly cooled samples from ore deposits.