Geological Summary

The Tres Vírgenes volcanic complex contains the only large stratovolcanoes in Baja California, rising above the Gulf of California in the east-central part of the peninsula. Three volcanoes, El Viejo, El Azufre, and La Vírgen, constructed along a NE-SW line, are progressively younger to the SW. The youngest, La Vírgen, is a stratovolcano with both dacitic and andesitic flank lava domes and lava flows. A major Plinian eruption from a SW-flank vent was radiocarbon dated at about 6,500 years, but Helium exposure and Uranium-series dates give a Pleistocene age (30.7 ka) for this event (Schmitt et al., 2006). A stratigraphic review (Avellan et al., 2018) noted that the 30.7 ka age is closer to the expected age of the tephra fall, and that the 22-25.5 ka (as determined by Schmitt et al., 2006) andesitic-dacitic lava flows dispersed around the cone are the youngest units in the complex. Although an ash plume from Tres Vírgenes was reported in 1746 by a Spanish Jesuit priest while navigating the Gulf of California, no tephra deposits from such a recent eruption have been found. A geothermal plant is located at the northern end of the complex near the margin of the Pleistocene El Aguajito caldera.

This volcano is located within the El Vizcaino, a UNESCO Biosphere Reserve property.

References

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography.

Avellan D R, Macias J L, Arce J L, Jimenez-Haro A, Saucedo-Giron R, Garduno-Monroy V H, Sosa-Ceballos G, Bernal J P, Lopez-Loera H, Cisneros G, Layer P W, Garcia-Sanchez L, Reyes-Agustin G, Rocha V S, Rangel E, 2018. Eruptive chronology and tectonic context of the late Pleistocene Tres Vírgenes volcanic complex, Baja California Sur (México). Journal of Volcanology and Geothermal Research 360, p. 100-125. https://doi.org/10.1016/j.jvolgeores.2018.06.012

Capra L, Macias J L, Espindola J M, Siebe C, 1998. Holocene plinian eruption of La Virgen volcano, Baja California, Mexico. J. Volcanol. Geotherm. Res., 80: 239-266.

Mooser F, Meyer-Abich H, McBirney A R, 1958. Central America. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 6: 1-146.

Sawlan M G, 1991. Magmatic evolution of the Gulf of California rift. In: Dauphin J P and Simoneit B A (eds) The Gulf and Peninsular Province of the Californias, Amer Assoc Petrol Geol Mem, 47: 301-369.

Schmitt A K, Stockli D F, Hausback B P, 2006. Eruption and magma crystallization ages of Las Tres Virgenes (Baja California) constrained by combined 230Th/238U and (U-Th)/He dating of zircon. J. Volcanol. Geotherm. Res., 158: 281-295.