We used to think that the deepest sources of water were old.

The briny remnants of ancient seas that make up the base of many groundwater systems may not be completely isolated from the world above.

The water in the region had been flushed down as deep as three kilometers.

It would have taken between 400,000 and 1.1 million years for the fresh influx to arrive.

The water at the base of the Paradox Basin has probably been trapped there for hundreds of millions of years.

How did a bunch of fresh, younger water get so deep, so quickly?

Grant Ferguson says that thehings are more dynamic than he thought.

The findings are based on a special form of dating that can take much longer to find than radiocarbon dating.

It takes more time to decay than carbon. It can be used to estimate the age of water.

Researchers discovered deep circulation of water from the surface when they applied this technique to gas samples.

The older, saltier water appears to have been partially diminished by the young water components in the deepest waters.

This might not be the case in other systems, but in the Paradox Basin, it is possible to see water in the air.

A period of widespread erosion under the riverbed occurred about 10 million years ago.

The results show that the United States needs to be more cautious about how it handles its water. If the basin is churned up so quickly, any pollutants from agriculture, landfills, or sewage could get to deep levels more quickly than expected.

Over a third of the United States and almost all of the rural population have access to drinking water from the ground. Older, deeper water also naturally replenishes rivers and lakes.

It takes a long time to refill if a lot of the system is tired. Diluted contaminants are a problem.

In the US, a study found that one in five samples contained a contaminant.

"We will have these legacies going forward, whether that's in storing fluids from oil and gas, or carbon sequestration."

I don't think we've really looked at these systems in the way we should.

There was a study published.