Rhyolite pumice fall and pyroclastic flow deposits from the two caldera-forming eruptions (Arce and Congo) at Coatepeque are exposed in this quarry wall. The lower Arce pumice and overlying pyroclastic flow deposit have a total volume about 40 km³ and were emplaced during the 72,000 BP eruption that formed the NE part of the caldera. The upper deposits (above the undulating brown paleosol in the center of the photo) are from the 16 km³ 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).

This image is made available under the Creative Commons BY-NC 4.0 license terms.

Keywords: pumice | tephra | stratigraphy | geology | outcrop

Coatepeque Caldera