Major challenges in volcanology are the abilities to recognise if, when and how fast magmatic systems can switch from states of dormancy into states of unrest or eruption. Despite an increasingly large body of geophysical information on magma migration and accumulation within magma plumbing systems, there are currently no integrated views on how mush-dominated magma plumbing systems evolve in space and time, how magma is stored, transferred and processed within these systems and how mush processes affect the behaviour, duration and intensity of volcanic eruptions. This is particularly critical as mush processes can perturb seemingly dormant or steady-state volcanoes, leading to dramatic changes in behaviour. Thus, understanding the dynamics of mush-to-magma conversion is not only important for describing the physical evolution of magma plumbing systems, but is also vital for carrying out effective volcano monitoring and risk assessment.

In this session we welcome contributions that use the physical and chemical properties of volcanic eruption products, and those of crystals in particular, to improve our understanding of mush-bearing magma plumbing systems. We especially welcome contributions that focus on critical timescales of magma storage, re-mobilisation and transfer within mush-bearing systems as well as those that investigate and compare rates of mush-to-magma conversion in chemically distinct systems. We also invite contributions that exploit recent improvements in analytical, experimental and computational techniques to extract P-T-t-X conditions of mush processes more generally. Contributions that consider the implications of mush-to-magma conversion for volcano monitoring and risk assessment are also highly welcome.
The volcanic-plutonic connection has been postulated mostly based on indirect evidence coming from geochemical, petrological, and geophysical approaches, and theoretical modelling. However, very few direct field examples of such connection have been offered. The reason is that most well exposed volcanic terrains are so young for erosion or tectonics to have exhumed their deeper plutonic roots, while plutonic terrains are too old to preserve possible coeval volcanic equivalents. The Pyrenees, an Alpine mountain range located between Spain and France, offers an exception to this general rule, and exposes co-genetic and coeval plutonic, subvolcanic and volcanic rocks that offer good field evidence of the existence of such plutonic-volcanic connection. A significant portion of the continental crust ranging in age from the Cambro-Ordovician to Permian, exposes two examples of such connection corresponding to the upper Ordovician and the Upper Carboniferous-Lower Permian magmatic episodes. In both cases, volcanic rocks are the eruptive expression of these magmatic episodes, which also generated large plutonic bodies and subvolcanic dyke complexes emplaced at very sallow depths. The field-based stratigraphic and structural reconstruction of some of these plutonic-subvolcanic-volcanic complexes, as well as new zircon U-Th radiometric ages and petrological and geochemical data, demonstrate that there was a time-space and genetic relationship between them, thus offering one of the scarce direct evidence of the existence of the so many times postulated but still not clearly proved plutonic-volcanic connection., This research is supported by MINECO grant SIMPROP (CGL2017-84901-C2)