Abstract
The mixing and mingling of magmas of different compositions are
important geological processes. They produce various distinctive
textures and geochemical signals in both plutonic and volcanic rocks and
have implications for eruption triggering. Both processes are widely
studied, with prior work focusing on field and textural observations,
geochemical analysis of samples, theoretical and numerical modelling,
and experiments. However, despite the vast amount of existing
literature, there remain numerous unresolved questions. In particular,
how does the presence of crystals and exsolved volatiles control the
dynamics of mixing and mingling? Furthermore, to what extent can this
dependence be parameterised through the effect of crystallinity and
vesicularity on bulk magma properties such as viscosity and density? In
this contribution, we review the state of the art for models of mixing
and mingling processes and how they have been informed by field,
analytical, experimental and numerical investigations. We then show how
analytical observations of mixed and mingled lavas from four volcanoes
(Chaos Crags, Lassen Peak, Mt. Unzen and Soufrière Hills) have been used
to infer a conceptual model for mixing and mingling dynamics in magma
storage regions. Finally, we review recent advances in incorporating
multi-phase effects in numerical modelling of mixing and mingling, and
highlight the challenges associated with bringing together empirical
conceptual models and theoretically-based numerical simulations.