Gutanasar, Mountain summit in Kotayk Province, Armenia

Gutanasar is an extinct volcanic cone in the Geghama mountains of Kotayk Province, reaching 2,299.6 meters with about 300 meters of relative height. Its crater is breached on the south side, and its slopes incline at 25 to 45 degrees. The mountain holds perlite and pumice deposits.

This is an extinct volcano whose final eruption occurred roughly 200,000 years ago, determined through scientific dating of surrounding lava flows. That volcanic past has shaped the geological features visible at the site today.

Gutanasar is one of the common sources of obsidian found in Armenian archaeological sites. The volcano's lava flows produced the glassy stone that toolmakers worked into blades and implements, and the mountain also holds deposits of perlite and pumice.

Gutanasar lies 2.5–3 km south of Fantan village and 4 km northeast of Jraber, on the northern edge of the Kotayk plateau. Its slopes are steep, between 25 and 45 degrees, so plan the approach from the Fantan side and allow time for the climb. The summit area is meadow, the lower slopes mountain steppe.

Gutanasar's lava flows were dated by the argon-argon (Ar39/Ar40) method to about 200,000 years before present, which fixes the age of its last eruption. The same flows made the volcano one of the common sources of obsidian found at archaeological sites across Armenia.