Cross section through a lahar deposit rock sample found in the proglacial area of Breidamerkurjokull, an outlet glacier of the Vatnajokull icecap in southeastern Iceland. Subangular clasts of various volcanic rock types were deposited after a flood and later solidified to form this rock. Dark basaltic clasts contrast with lighter coloured components with higher silica content. The image is about 25 centimetres wide.