Rapid mixing and short storage timescale in the magma dynamics of a steady-state volcano

摘要

Steady-state volcanic activity implies equilibrium between the rate of magma replenishment and eruption of compositionally homogeneous magmas, lasting for tens to thousands of years in an open conduit system. The Present-day activity of Stromboli volcano (Aeolian Islands, Southern Italy) has long been recognised as typical of a steady-state volcano, with a shallow magmatic reservoir (highly porphyritic or hp-magma) continuously refilled by more mafic magma (with low phenocryst content or lp-magma) at a constant rate and accompanied by mixing, crystallisation and eruption. Our aim is to clarify the timescale and dynamics of the plumbing system at the establishment of the Present-day steady-state activity (1.2 ka) to pinpoint the onset of the steady-state regime. We investigated the Post-Pizzo (PP) pyroclastic sequence (similar to 1.7-1.5 ka) and one of the Early Paroxysms (EP) of the Present-day activity, focusing on the clinopyroxene population.