Global Volcanism Program | Image GVP-07285
Rhyolitic pumice-fall and pyroclastic-flow deposits from the two caldera-forming eruptions (Arce and Congo) at Coatepeque are exposed in a quarry wall. The lower Arce biotite-bearing pumice-fall and overlying pyroclastic-flow deposit have a total volume about 40 cu km and were emplaced during the 72,000-year-old eruption that formed the NE part of the caldera. The upper deposits (above the brown paleosol in the center of the photo) are from the 16-cu-km Congo eruption prior to about 57,000 years ago and were erupted through a caldera lake.
Photo by Carlos Pullinger, 1996 (Servicio Nacional de Estudios Territoriales, El Salvador).