Ubehebe holds fire (in Death Valley)

By Dave Armstrong - 23 Jan 2012 23:14:33 GMT
Ubehebe holds fire (in Death Valley)

Death Valley's half-mile-wide Ubehebe Crater turns out to have been created 800 years ago - more recently than generally thought; Credit: Brent Goehring/Lamont-Doherty Earth Observatory

Holding out for 6000 years, scientists had believed that California's 600 feet deep Ubehebe Crater was an ancient volcanic creation, verified by the age of Native American artefacts beneath it. Forget that! Only 800 years ago, in 1300 AD, all hell reigned in Death Valley, meaning there is life likely below, in the tectonics. That is, the ground water below the surface can interact with nearby magma chambers to repeat the (relatively) recent blow out.

Geochemists from Columbia University's Lamont-Doherty Earth Observatory dated the rocks blown out of the crater of Ubehebe by superheated steam, ash and deadly gases. Lead author Peri Sasnett is shown below contemplating a sample of these small rocks:

ubehebe crater

Credit: Brent Goehring/Lamont-Doherty Earth Observatory

Brent Goering (now at Purdue University) and Nicholas Christy-Blick (two of the other authors) were on a student field-trip, investigating the sandstone and quartzite thrown from the crater Studying the beryllium isotopes and their decay by means of cosmic rays, the time of their exposure to the rays was an estimated 2100 to 800 years.

Smaller explosions (2100 years ago) would have culminated in, "the big one," in 1300AD. Other, numerous craters in the area are likely to have been produced by similar explosions. Every thousand years or less, the area is subject to this kind of deadly activity. Animal life within two miles or more would be flung around, suffocated, burned and bombarded! Dr. Goehring says, "It would be fun to witness - but I'd want to be 10 miles away," but a better personal preference is to stay home.

The hydrology might have been thought to indicate other scenarios. Wet places are indicated for phreatomagmatic events. Death Valley is so dry that the geologists could be thought wrong. Inevitably, the data agrees with the geology. If 1300 saw the explosion, it was even hotter and drier then than the present.

Stephanie Kyriazis, a park education specialist in geology, takes it on the chin. "This certainly adds another dimension to what we tell the public." (About a million people visit the park each year.) Don't ask what she says after the next explosion. Here is a map showing death valley between Las Vegas and Bakersfield. The fault lines that run through LA and the San Joaquin valley and several others indicate how close tectonic activity can occur -

rainforest deforestation.

Map of Los Angeles region via Shutterstock

The warning signs are to be shallow earthquakes, and steam venting from the ground for several years. Stephanie could try offering that as a tourist special for Dr Goehring. Already, Yellowstone to the east has boiled people alive, so a little competition is to be encouraged here. In 130 years, Yellowstone has had 20 small blowouts, while the intrepid Ms. Kyriazis pours cold water on the whole discussion." "Right now, we're not planning to issue an orange alert or anything like that," she said.

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