The topographic high point of the fault-bounded central horst of La Yeguada volcanic complex is Cerro el Castillo (right center). It and Cerro Novillo at the lower right are part of older Miocene rocks uplifted in the horst. Quaternary volcanism took place in the northern part of the horst, out of view to the right, about 220,000 years ago. In the background are extensive Tertiary ignimbrite deposits of La Yeguada formation, some of which are thought to have originated from vents in the central horst.

Photo by Tom Casadevall, 1994 (U.S. Geological Survey).

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

La Yeguada