Short-term magma-carbonate interaction: A modelling perspective

Abstract

The short-term, syn-eruptive interaction of magma with crustal carbonates can largely affect the eruptive style and drive even low-viscosity magmas toward large explosive eruptions. Only a few studies focus on the short-term interaction and the physical processes behind the experimental observations are still poorly understood. In this work, we study for the first time the short-term magma-carbonate interaction process through a modelling approach that provides an interpretative key of the experimental and field observations. We developed thermodynamic and dynamic models for the carbonate dissolution and the mixing and mingling between the contaminated magmapockets and the host magma. We find that mixing and mingling can play a central role in modulating the efficiency of volatile exsolution. The increasing viscosity of the host melt slows down the mingling, hence the mixing process, limiting volatile exsolution. Less efficient mixing and mingling imply that the fingerprints of the short-term magma-carbonate interaction can be preserved in the volcanic deposits. Finally, we highlight a key question that needs to be answered to constrain the mechanism and timescale of the carbonate dissolution process.