Charles Ferguson and colleagues describe the discovery of a volcano in the Mojave Desert of the southwestern United States that has implications for understanding the mechanism for super-eruptions, a class of volcanic eruption that taps very large (greater than 100 cubic kilometers) amounts of magma in a very short period of time (hours to days).
Their paper includes new geochronological data confirming that densely welded volcanic ash within the volcano is the same age as a widespread outflow sheet of the ash that extends across over 14,000 square kilometers of the Mojave Desert. In addition, they identify a fragment of the volcano that was tectonically dismembered and translated more than 30 kilometers to the southwest between approximately 19 and 15 million years ago.
The direction of extension is compatible with previous estimates derived from detailed structural analysis of the region.
Charles A. Ferguson et al., Arizona Geological Survey, 416 West Congress, Suite 100, Tucson, Arizona 85719, USA. Posted online 19 October 2012; doi: 10.1130/G33551.1.