Kerið (64° 2’26.73″N 20°53’4.92″W) is a crater of scoria and splatter material of basaltic rocks. Scoria is broken and stiff lava fragments (mm – cm size). The rocks were derived from the spray of the lava fountains during the fissure eruption, that formed Kerið. When scoria fragments hit the ground, they are already solidified and stiff. In contrast, spatter fragments, which are also derived from the spray of the lava fountain, hit the ground when they are still hot and plastic (“pancake-like” shape). The scoria is mostly black or red in colour. The black colour is the most common and the red colour is due to oxidation (Guðmundsson, 2017).
Kerið belongs to the volcanic field, called Grímsnes Volcanic Field. The whole field was generated in many eruptions that occured around 8,000 – 10,000 years ago and formed several crater cones by fissure eruptions. Kerið itself was formed around 9,000 years ago and was supplied with magma from a north-northeast trending volcanic fissure (about 900 m long). The crater has a small lake inside, which is based on the reason that the water level marks the water table, the surface of the groundwater (Guðmundsson, 2017).
Guðmundsson, Á. (2017). The glorious geology of Iceland’s Golden Circle. Springer. 334 pp.