Magma mixing

In order to increase our understanding of magma mixing processes
and their impact on the geochemical evolution of silicate melt we
present in the following works, the first set of experiments
performed using natural basaltic and rhyolitic melts. In
particular, we investigate the interplay of physical dynamics and
chemical exchanges between these two melts using time-series mixing
experiments performed under controlled, chaotic, dynamical
conditions. The variation of major and trace elements is studied in
detail by electron microprobe (EMPA) and Laser Ablation ICP-MS
(LA-ICP-MS) and the time-evolution of chemical exchanges during
mixing is investigated. Using the concentration variance as a proxy
to measure the rate of chemical element homogenization in time, a
model to quantify chemical element mobility during chaotic mixing
of natural silicate melts is proposed. The morphology of mixing
patterns at different times is quantified by measuring their
fractal dimension and an empirical relationship between mixing time
and morphological complexity is derived. The complexity of mixing
patterns is also compared to the degree of homogenization of
chemical elements during mixing and empirical relationships are
established between the fractal dimension and the variation of
concentration variance of chemical elements in time. Finally we
discuss the petrological and volcanological implications of this
work.