In Death Valley, ancient volcano gives scientists a surprise
The Ubehebe crater in Death Valley National Park is much younger than previously thought, and represents a more significant volcanic hazard than previously thought, according to a new study.
(Page 2 of 2)
At the time, Death Valley hosted a vast freshwater lake. The valley and the area around the lake would have held plenty of water for rising magma to flash-boil into steam.Skip to next paragraph
In Pictures Chile's Puyehue volcano erupts
Subscribe Today to the Monitor
The team estimates, however, that Ubehebe's eruption and that of smaller craters in the surrounding area could have started some 2,100 years ago and perhaps as recently as the 1300s – a span that included a prolonged period of extreme dryness in the Southwest, including Death Valley.
The new date range decoupled the eruption from a wet climate and sent the team looking for other sources of moisture.
The researchers used a technique based on the radioactive decay of beryllium-10 for dating rocks gathered from around Ubehebe in January and March of 2009.
Using previous estimates of the volume of rock ejected during Ubehebe's blast, the team calculated that it wouldn't take much magma – a blob no more than about 600 feet across – and a smaller volume of water to punch out Ubehebe's crater.
Such small deposits of groundwater could have survived the arid conditions at the time, and could well exist today, the team suggests. Based on the locations of springs in Death Valley today, the team estimates that groundwater may exist within about 500 feet of the crater floor.
A magma source today, however, may be a bit more difficult to pin down. Geophysicists trying to figure out what's underneath Death Valley have come up with conflicting evidence for the presence of liquid or semi-liquid magma.
In a study published last year, researchers from the University of Texas at El Paso used four independent lines of evidence to infer magma's presence. They estimate the magma is trapped some 15 miles below the valley floor.
The team, led by Musa Hussein, cautions that more work needs to be done to establish whether the magma there is molten or partially molten.
All of which says to Goehring and colleagues that while their results suggest the volcanic field Ubehebe occupies "may constitute a more significant hazard than generally appreciated," it's not time to dump annual park passes on unsuspecting eBay bidders.
"I'd hang on to them," he says of any park passes. Death Valley "is still worth going to."