Figure 2

Example images from tape-on-paper slides ( ∼ 75 × magnification). (a) Volcanic ash in a sample from Lerwick. The grains are very small (< 25 μ m), but still recognisable by their glassy, brownish colour. Often, the grains form aggregates. (b) Mineral grains (non-volcanic). The grains, mainly sand, are blown around by strong winds and are found in most tape-on-paper samples. They vary in shape and size and, in this example, are much larger than the volcanic ash grains (> 100 μ m). (c) Black, opaque grains, such as in the bottom right, were common in the tape-on-paper samples and are probably soot. (d) Biological materials, such as pollen, bits of leaf and insects, were also found in most tape-on-paper samples.