Disequilibrium viscosity of Stromboli basalt: Implications for magma dynamics in active basaltic systems

Magma ascending through Earth's crust undergoes complex chemical and physical changes that may induce crystallization, a solidification process that deviates from the thermodynamic state of equilibrium. The diverse cooling and deformative regimes suffered by magmas heavily influence crystallization rates, solidification timescales, and consequently, the rheological evolution of magma. This, in turn, significantly impacts the dynamics of volcanic plumbing systems and the associated eruptive styles. We investigate the rheological changes in Stromboli magma (Italy) during disequilibrium crystallization under non-isothermal sub-liquidus conditions. By systematically varying the cooling rate (1-10 °C/min) and the shear rate (1-10 s-1), we found that cooling rates significantly influence the solidification path of the basalt, while shear rates have a subordinate effect. By comparing our results with literature data on basalts from Mt. Etna (Italy), we observed distinct timescales and rates of solidification, contributing to unique eruptive dynamics in these volcanic plumbing systems.