The origins of the Peach Springs Tuff can be spotted in southwestern Arizona's Black Mountains, near the town of Oatman. The eruption left behind a very large crater called a caldera, though it has been mostly obliterated by erosion and faulting.
The caldera, called Silver Creek, spewed magma for several days, releasing a volume of about 1,000 times the Mississippi River's daily flow at New Orleans, Valentine said. "If you think about 1,000 Mississippi Rivers coming out of the ground, you can see how [the ash] would have spread out across a huge area," he said.
However, one expert on the Peach Springs Tuff doesn't buy the scenario. Charles Ferguson, a research geologi yroclastic flow.
"I think their hypothesis is more problematic than explanatory," Ferguson told Live Science.
Southwestern supervolcanoes The Peach Springs Tuff covers parts of Arizona, Nevada and California, from Barstow, California, to Peach Springs, Arizona. Geologists use the creamy white and pink rock as a unique marker in the region.