Seminar Lea Ostorero

Constraining the time elapsed between changes in magma storage conditions within a reservoir and the onset of eruption remains a major challenge in volcanology. Because direct observation of magma storage systems beneath volcanoes is not possible, these timescales must be inferred indirectly, notably through the study of crystals erupted during past volcanic events. Crystal zonations produced by a range of magmatic processes provide a means to quantify diffusion timescales, which can then be compared with monitoring signals recorded prior to recent eruptions. In addition, crystals preserve information on magmatic volatile contents (CO₂, H₂O, F, Cl and S) through melt inclusions trapped during crystal growth. These inclusions represent small pockets of melt encapsulated at depth and allow the reconstruction of magmatic volatile budgets, such as CO₂ budgets. Such budgets provide key constraints on the links between volatile degassing from magmas and climate evolution.

This presentation will highlight constraints on pre-eruptive timescales obtained from volcanoes in Kamchatka (Russia) and the Lesser Antilles, as well as the estimation of the pre-eruptive CO₂ volatile budget of magmas from a past magmatic province in Iran, and its possible implications on the lower Cenozoic climate.