Global Volcanism Program | Image GVP-07279
A volcanologist investigates an exposure of the Arce pyroclastic deposits on the eastern flank of Chilamatal caldera, about 10 km ENE of the rim of Coatepeque caldera. The Arce eruption about 72,000 years ago produced about 40 cu km of tephra and was associated with the first caldera-forming event at Coatepeque. The Arce deposits consist of two thick biotite-rich pumice-fall deposits, separated by thin ash-, pumice-, and lithic-fall deposits. Arce fall deposits are distributed over much of western El Salvador.
Photo by Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).