Trace Element Mobility During Magma Mixing: Preliminary Experimental Results

Magma mixing tests have been performed experimentally in a Taylor-Couette-like experimental setting. The variation of trace element concentrations along transects crossing the resultant melt column has been measured. Results indicate a strongly variable mobility of the different trace elements in the same mixing system. Such a different behaviour of trace elements tends to be enhanced as the mixing time increases, leading to the production of highly heterogeneous volumes of melts in which depletion and enrichment of trace elements occurred depending on their potential of spreading across the magma mixing system. The results presented here offer new insights into the complexity of processes expected to be operating during mixing of magmas. It is demonstrated that on short mixing times also the trace elements may become highly non-correlated. This is due to the development of chaotic advection/diffusion processes in the system. These results indicate that the onset of diffusive fractionation processes may strongly influence the patterns of data on inter-elemental diagrams depending on the relative mobility of the different elements.