Durango Volcanic Field

Pyroclastic-surge deposits from La Breña maar in Mexico's Durango volcanic field show both laminar and dune bedding forms. The thin beds (note the pen in the center for scale) were created by successive explosive eruptions that produced high-velocity, laterally moving pyroclastic surges that swept radially away from the volcano. The direction of movement of the surge clouds was from right to left, as seen from the truncated dune beds on the near-vent side.