LAS VEGAS (KTNV) — As Lake Mead's water level continues to drop, scientists at UNLV have discovered sedimentary rock laced with volcanic ash that hasn't been visible since the 30s.
The combination of climate change-fueled drought and water overuse has caused Lake Mead's levels to drop to record lows, exposing sunken boats, warships and even human remains. So what is it about these rocks that have UNLV scientists so excited?
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A study conducted on the exposed rock revealed that many of the discovered deposits contain ash from volcanoes as far away as Idaho, Wyoming and California. Researchers also determined that the collected ash rained down on Southern Nevada nearly 12 million years ago.
“Ash from even moderately explosive eruptions can travel hundreds of miles from the source, blanketing entire areas with anywhere from a centimeter to several meters of the heavy material,” said Eugene Smith, a UNLV emeritus professor of geology.
Researchers found evidence of several volcanic blasts millions of years ago from places like the Snake River Plain-Yellowstone area, the Southwest Nevada volcanic field and the Ancestral Cascades, which includes Mount Saint Helens. The most recent ash discovered among the deposits was from an eruption only 32,000 years ago.
This poses potential risks, researchers say, because even a couple of millimeters of ash, especially when wet, can become incredibly heavy and take down power and telecommunications lines, as well as block roadways.
“Although the Las Vegas Valley is currently very far away from any active volcanoes, we can and will have ash from these volcanoes fall over Southern Nevada in the future,” Smith said.
UNLV’s team says studying the ash layers helps determine how often the Las Vegas area was inundated with ash over time and may help prepare for future events from active volcanoes far from us.
“Studying the past can help you plan for the future,” said CLAGR lab manager and longtime Southern Nevada geologist Racheal Johnsen. “The ash layers we study come from volcanoes long extinct. However, studying them has helped us determine just how often the Las Vegas area was inundated with ash over time and may help us prepare for future events from active volcanoes far from us.”
