In the western U.S., massive ignimbrite deposits up to several hundred metres thick occur in the Basin and Range Province, largely in Nevada, western Utah, southern Arizona, and north-central and southern New Mexico, and Snake River Plain.
The La Garita Caldera is a large volcanic caldera located in the San Juan Mountains in southwestern Colorado, United States, and is one of a number of calderas that formed during a massive ignimbrite flare-up in Colorado, Utah, and Nevada during the Oligocene Epoch.
El Hoyo, Monte Galan, Momotombo and Momotombito volcanoes are built upon ignimbrite deposits from the nearby Malpaisillo caldera.