Abstract

The crystal cargo of volcanic rocks is a heterogeneous assemblage of mineral populations of different origins and age ranges, recording complex histories of their journey through the volcano plumbing system prior to eruption. Timescales of pre-eruptive magmatic processes can be unlocked via elemental diffusion chronometry, a powerful and widely used tool exploiting the element exchange within a chemically zoned crystal or within a crystal and melt. Durations of pre-eruptive magmatic processes are quite variable and are system dependent. Timescales of magma storage between magma intrusion and eruption is relative short (from a few days to a few decades) for basaltic systems, but much longer (decades to millennia) for silicic systems. The short timescales recorded by crystals from mafic and intermediate volcanoes often match those recorded by monitoring signals (e.g., gas, seismicity, deformation, etc) and offer valuable information to inform volcano forecasting and hazards mitigation. Timescales of magma remobilisation and pre-existing crystals remobilisation, retrieved from the internal portions of chemically zoned crystals, provide information on the longevity of crystal mushes and are shedding new light particularly on basaltic crystal mushes, which may persist longer than previously hypothesised. Here, using recent examples from both terrestrial and extraterrestrial volcanoes, I will discuss how diffusion chronometry provides fundamental time-constrained insights into pre-eruptive magma dynamics. I will also focus on the challenges we face to progress diffusion chronometry, reducing uncertainties and favouring interdisciplinary approaches that link diffusion chronometry to real-time volcano observations and isotope geochemistry.