In the Reykjanes Fires 1210-1240 AD four different lava fields were formed on the two westernmost volcanic systems on the Reykjanes peninsula, i.e. the Svartsengi and Reykjanes volcanic systems. The Younger Stampar lava was emitted from a 4 km long, NE-SW trending, crater row on Reykjanes. The crater row , which is well preserved, is mostly composed of small barrel and bell-shaped scoria and spatter cones. The areal extent of the lava is 4.6 km2. The south end of the eruption fissure extended into the sea, resulting in surtseyan eruptions when magma came in contact with water. Two tuff cones formed at the shore. Parts of them are still preserved at the SW-coast.
Magnús Á. Sigurgeirsson, 2010