Mount Damavand first erupted in the Pleistocene almost 1.78 million years ago. After several known eruptions around 600,000 and 280,000 years ago, its last eruption was around 5300 BC in the Holocene. Its steep cone is formed of ash and lava flows mainly of trachyte, andesite, and basalt. The Quaternary lavas are directly on the Jurassic sediments. The volcano is crowned by a small crater with sulfuric deposits. There are also fumaroles, hot springs, and mineral deposits of travertine. Mount Damavand could be considered as a potentially active volcano, because there are fumaroles near the summit crater emitting sulfur, which was known to be active on July 6, 2007.