(ORDO NEWS) — Falling water levels in America’s Lake Mead in recent months have revealed some shocking things – previously sunken boats, old warships and human remains.
Now scientists are reporting a new discovery on a dried-up lakebed: rocks riddled with volcanic ash, they are evidence of eruptions some 12 million years ago.
The record low water level is exposing sediment that has not been seen since the 1930s, when the Hoover Dam was built and water filled Lake Mead.
Among these rocks, researchers at the University of Nevada at Las Vegas found deposits of ash from volcanoes in Idaho, Wyoming and California.
“We knew these units of ash existed, but were surprised to find so many of them when the water level in Lake Mead dropped,” said Eugene Smith, emeritus professor of geology at UNLV and co-author of the study.
A drought caused by climate change in the West and overuse of the Colorado River’s water has caused Lake Mead’s water levels to reach an all-time low.
As of September, the lake’s water level was only 1,045 feet above sea level, or about 27% of its full capacity.
Scientists are using the low levels to study sediments that have not been affected for almost a century.
Smith’s research team found white to gray volcanic ash. They took samples to their lab to pinpoint the source of the ash, but it is already clear that it was not a single eruption, writes CNN.
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