- Associated Press - Tuesday, May 24, 2016

LINCOLN, Neb. (AP) - Authorities say what’s believed to be a 600,000-year-old vein of volcanic ash has been uncovered at a landfill just north of Lincoln.

The city said in a news release Monday that the ash was found during excavation work.

Alfred Benesch & Co. engineer Greg Westphal, who is overseeing the contract for a landfill expansion, said finding ash in the area isn’t unusual, but its size is. The vein is estimated at 250 feet long, 5 to 15 feet wide and 4 to 5 feet deep.

The ash was discovered underneath the glacial till, sitting in what would’ve been a glacial lake that formed in front of ice sheets hundreds of thousands of years prior. Westphal said he believes the deposit might be a drift, pushed up against a stream.

Westphal wants to send samples to the state geologist, who will officially date it. But he’s believes it came from a volcanic eruption in what is now Yellowstone National Park in northwest Wyoming.

The deposit was found in an area that’s currently being prepared for expanded garbage and trash deposits. The city expands the landfill about every three years by opening up a new area called a cell, said Donna Garden, assistant director for Public Works and Utilities.

A contractor excavates dirt and puts layers of clay, plastic, gravel and felt at the bottom of the cell in order to prevent liquid from the garbage and trash from seeping into the groundwater, said Karla Welding, superintendent of solid waste operations.

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