Geology

The geology of the Jemez Mountains has sparked scientific discoveries of worldwide value and renown, but there is much left to learn.

The Jemez volcanic field is located at the intersection of two major fault systems, the Rio Grande Rift and the Jemez Lineament. The rift, a stretching and thinning area of the earth’s crust, extends from central Colorado to the state of Chihuahua, Mexico, and the lineament, a chain of volcanic fields, spans from east-central Arizona to the Raton-Clayton volcanic field in northeastern New Mexico.

The Jemez volcanic field started forming more than 14 million years ago with a series of eruptions, including at least two especially explosive events. The most recent event (about 1.25 million years ago) formed Valles Caldera, whose central resurgent dome, Redondo Peak, serves as the type locality (or model) for understanding caldera resurgence worldwide.