The Tres Vírgenes volcanic complex contains the only large stratovolcanoes in Baja California.  The roughly 1940-m-high complex rises above the Gulf of California in the east-central part of the peninsula.  Three volcanoes, El Viejo, El Azufre, and La Vírgen were constructed along a NE-SW line and are progressively younger to the SW.  The youngest volcano, La Vírgen, is an andesitic stratovolcano with numerous dacitic lava domes and lava flows on its flanks.  A major plinian explosive eruption from a SW-flank vent was radiocarbon dated at about 6500 years ago, but Helium exposure and Uranium-series dates give a late-Pleistocene age for this event.  An ash plume was reported from Tres Vírgenes volcano by a Spanish Jesuit priest while navigating the Gulf of California in 1746.  No tephra deposits from such a young eruption have been found, but young undated andesitic lava flows at the summit could potentially be related to this event.  A geothermal plant is located at the northern end of the complex near the margin of the Pleistocene El Aguajito caldera.