Pyroclastic surge deposits surround the Cerro Colorado maar of the Pinacate volcanic field in NW México. These thin beds (note the coin for scale) were formed by successive explosions that produced pyroclastic surges. The light-colored rock in the center of the photo is a ballistic block that impacted the surface of earlier surge deposits, compressing them and forming a small pit called a bomb sag.

Photo by Richard Waitt, 1988 (U.S. Geological Survey).

This image is made available as a Public Domain Work, but proper attribution is appreciated.

Galleries: Pyroclastic Flows

Keywords: deposit | stratigraphy | pyroclastic density current (PDC) | field work | geology | pyroclastic surge | ballistic ejecta | block

Pinacate