The black layer ~10cm (above the little shovel) deep is tephra ash layer from the Katla volcano eruption in 1500! Under the redish shovel, is a darker layer showing the settlement in 874, when the first people arrived in Iceland (started tilling the land, had horses, sheep, animals that changed the soil). Further down, about 7000 years of lake sediments, even old tree stumps that old! (More pics in gallery).
tephra ash dated 1500 (fingertips).
Lots of field trips in university here! Very cool way to learn. Soils & Vegetation field trip told a story of Iceland's history. Each volcanic eruption is saved in the soil, to keep a record. It takes sooooo long to make soil, and how quick to deplete or change or destroy it. The black layer nearer the surface is tephra ash layer from year 1500 of the Katla volcano eruption. Further down, where the soil is darker is when the settlement in 874 in Iceland when the first people settled from Norway. soil changed, from tilling, animal grazing, trees cut down, erosion, etc. Further down in a layer a colleague found a tree stump 6000-8000 year old tree stump in what used to be a wetland from organic matter. Most students in this group were from all over Europe.