In the new report, published in the 18 January issue of Geophysical Research Letters, Goehring and his colleagues suggest such an event created Ubehebe (pronounced YOU-bee-HEE-bee) volcanic crater, the youngest and largest of a dozen similar craters in northern Death Valley.
What's more, conditions may be ripe for a repeat performance.
Geologists had long assumed that Ubehebe and its sister craters were thousands (or even tens of thousands) of years old. Those supposed ages would put the eruptions at the end of the last ice age, when the U.S. southwest was considerably wetter than it is today. And that made perfect sense, considering all geologic clues suggest the magma mixed with water, which is what made them so explosive.
Called phreatomagmatic eruptions, such events usually occur where water is abundant-near the edge of a lake, say, or at the bottom of the ocean:
But when the Lamont geochemists used a new-fangled isotope technique to date the volcanic craters, they turned out to be surprisingly young. They ranged from 2,100 years old to 800 years old-meaning they formed long after California had dried out.