Protection Status
Tröllabörn was designated a natural monument in 1983. The natural monument is characterised by unusual lava spires (hornitos), which have historically been used as sheep shelters and, in some cases, temporary refuges for travellers. These formations were created when volcanic gases escaped through openings in flowing lava. As the gases emerged and came into contact with oxygen in the atmosphere, they burned at extremely high temperatures. Fragments of molten lava carried upward by the gases gradually accumulated, forming small but steep cone-shaped structures. Such formations, known as lava spires or hornitos, are especially common on shield volcano lava fields.