Scientists studied 240,000 years of data about America’s ‘Dead Sea’ and found that it was 10 times bigger and much less salty than today

A new study has found that the Great Salt Lake in Utah, also known as America’s ‘Dead Sea,' was approximately ten times larger than its current size and also much less salty in the past. New claims about the lake emerged in a new study published in 2026 in Paleoceanography and Paleoclimatology. The study goes as deep as 240,000 years into the history of the lake.

The Great Salt Lake is up to 10 times saltier than seawater in some areas. Currently, it covers an area of approximately 4,144 square kilometers (1,600 square miles). The study clearly suggests that it has been much larger and much less salty in the past.

How was the research conducted

As a part of the research, scientists from the United States analyzed a 120-meter (394-foot) sediment core obtained from the lake bed. They dated its layers by the radioactive decay of the minerals it carried.

They also measured tiny chemical signals left by microbes to estimate and understand salinity. It was ascertained that the abundance and type of organisms living in the water changed with changes in salt concentration.

According to Science Alert, two separate periods of time were identified when the water was much fresher and salinity was also lower, coinciding with times when it covered a much wider area. Previous research classified these two larger bodies of water as Lake Bonneville (from about 30,000 to 16,000 years ago) and Little Valley (from about 140,000 to 135,000 years ago).


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The size difference as the lake swelled and shrank is comparable to the difference between a puddle and a pond, the outlet reported, citing the researchers. "If you scaled this up to the size of the present Great Salt Lake, that's probably what it looked like," Earth scientist Rachel So, from the University of Southern California (USC), was quoted as saying by Science Alert.

"For most of the past 240,000 years, the lake stayed about the same size but briefly grew 10 times larger on two separate occasions." As far as the measure of saltiness is concerned, the study claims that apparently Little Valley may have remained slightly salty, according to the sediment record. On the other hand, Lake Bonneville was a genuine freshwater lake.