Alkaline melts obtained from natural rocks were stirred together, curing a time series melting experiment. The samples were loaded as cylinders and forced convection was applied y the rotation of a spindle within a double cylinder at constant high temperature and deformation rate. The melts mingled and further mixed into differently homogenised single cells. After 16 and 25h stirring, the single cells decoupled into two convection cells of distinct compositions. Microprobe data indicate a complex layering of cells bounded by chemical discontinuities. Main mixing products consist of a top and a bottom cell (mixed composition between the two starting materials). With time increase, the upper cell shows spreading horizons for Al2O3, SiO3 and K2O. A second chemical discontinuity is suggested due to the change from a well mixed into a gradient layer.
