Volcanic Ash From Millions of Years Ago Discovered in Lake Mead

Posted: October 13, 2022 1:48 pm

The water crisis in Lake Mead is continuing to reveal new discoveries. Over the past few months, rapidly dropping water levels have exposed a number of artifacts, including ancient war ships, sunken boats, and even multiple instances of human remains. The latest discovery is rocks containing volcanic ash, indicative of a volcanic explosion in the region approximately 12 million years ago.

Plummeting Water Levels Expose Sedimentary Rocks

Researchers from the University of Nevada in Las Vegas (UNLV) are investigating the sedimentary rocks that were exposed as a result of the falling water levels in Lake Mead. These rocks have not been visible since the 1930s when the lake was first filled after the construction of Hoover Dam.

The researchers were able to identify ash deposits from volcanoes believed to have been located in Idaho, California, and Wyoming. Although the scientists knew that the volcanic ash existed in these rocks, they were surprised to discover the large amount present on the bed of the lake.

The water level in Lake Mead has fallen to unprecedented lows due to the ongoing drought and what experts say is an overuse of the water from the Colorado River, feeding into the lake. According to the latest data, Lake Mead’s water level was sitting at 1,045 feet above sea level. This level is only 27% of the lake’s full capacity.

While the decreasing lake level is certainly bad news for those who depend on it for their water supply, scientists have been able to use these low levels to further their research on sediment that has not been seen for nearly 100 years.

The UNLV research team discovered volcanic ash ranging in color from white to gray scattered through the rocks and sediment in the lake. The scientists took the samples back to their lab to determine the source of the ash. What they found is that the ash did not come from just one specific eruption.

Instead, the ash is a result of many volcanic eruptions throughout at least three states from millions of years ago. The eruptions came from volcanoes that stretched across an area that is now known as Yellowstone National Park.

Why is This Information Important?

The discovery sheds new light on how far ash from volcanic eruptions can travel, helping scientists to understand future risk. For example, the data may be used to reconstruct the volcanic history of this corner of the country and to learn more about how often these eruptions may occur in the centuries ahead.

The ash and sediment from volcanoes can spew hundreds of miles. This ash poses a significant health risk to all in its path. In addition, the eruptions can severely disrupt transportation, supply chains, and more. Understanding what to expect as far as impact and duration from these events will help officials near active volcanoes adequately prepare. This information is instrumental in constructing natural disaster plans for local governments.

There are currently about 170 volcanoes that are considered to be active in the U.S. The majority of these active volcanoes are located in Alaska. Other states on this list include California, Oregon, Washington, Hawaii, Idaho, Utah, New Mexico, Arizona, Colorado, and Wyoming.

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