Guadalupe volcano is a mostly submerged volcano that forms the island of the same name 250 km west off the coast of Baja California. The volcano was built on the old axis of an ancient spreading center and consists of 2 overlapping shields, the southern of which is the older.
The younger northern volcano could still be active and has probably erupted during the Holocene.
Elongated Guadalupe Island lies atop a fossil oceanic ridge crest and rises above the Pacific Ocean surface to an elevation of 1100 m.
Chains of cinder cones are located along fissures oriented both NW-SE and NE-SW and lava flows erupted from them overlie both shield volcanoes. The longest of these fissures cuts across the caldera of the northern volcano and extends beyond it to the SE.
Other pyroclastic cones were constructed along an arcuate fissure near the southern caldera rim. The shield volcanoes and products of the fissure eruptions form a complete alkali basaltic-to-trachytic series reflecting a transition from submarine to subaerial volcanism.
Trachytic lava domes are found within the caldera of the northern shield volcano, and together with very fresh-looking alkali basalt lava flows, form the youngest volcanic rocks on the island.
