Volcanic Formations

Formations produced directly by volcanic activity, the cooling of lava or magma, or the eruption and later erosion of volcanic material, following the volcanic landform class of standard geomorphology. Includes columnar basalt formed by the slow, even cooling and contraction of a lava flow (Giant's Causeway, Fingal's Cave, The Organ Pipes), volcanic plugs and necks exposed by the later erosion of a softer surrounding cone (Devils Tower, Shiprock), a lava tube formed by a flow that crusted over while still draining (Manjanggul Cave), and formations shaped in volcanic ash and tuff by later erosion (Cappadocia Fairy Chimneys, Sigiriya Rock). Belongs here: any formation whose defining material or shape traces directly to volcanic eruption, lava flow or magmatic intrusion. Does not belong here: a formation shaped by weathering or dissolution acting on rock with no volcanic origin (Erosional and Karst Formations), or a residual crystalline monolith left by the erosion of surrounding rock rather than built by an eruption (Inselbergs and Crystalline Monoliths).