Global Volcanism Program | Image GVP-10002
The southern flank of Socorro volcano is underlain by rocks of three distinct origins. On the lower flanks are alkaline basaltic rocks of the Lomas Coloradas unit mostly erupted between about 150,000 and 70,000 years ago. The middle flanks contain precaldera and syncaldera trachytic and rhyolitic ashflow deposits erupted between about 540,000 and 370,000 years ago. The summit region, including Cerro Evermann (center horizon), consists of silicic peralkaline rocks erupted between about 180,000 to at least 15,000 years ago.
Photo by Martha Marin, 1998 (Mexican Navy).