Figure 4

Palagonite series, note differences in the x and y scale between panels. The time of first illumination by the lamp is given by a vertical grey bar. From top to bottom 1 wt% 1-10 μm particles, 3 wt% 1-10 μm particles, 3 wt% 1-10 μm particles following excavation of the top 1 cm of sample, 6 wt% 1-10 μm particles, 9 wt% 1-10 μm particles, 25 wt% 1-10 μm particles, 9 wt% 76-105 μm particles Only dust contents 9 wt% and 25 wt% are heavily fractionated by the end of their runs, while all ices contaminated with fine dusts show some degree of increasing fractionation with time.