Great Salt Lake’s ancient past reveals how quickly fresh water can disappear

Great Salt Lake’s ancient history included two periods when the lake was much larger and far less salty. (Composite: Rhiannon Montelius. Image source: Wikimedia Commons.)

Great Salt Lake’s ancient past reveals how quickly fresh water can disappear

Research led by USC Dornsife Earth scientists traces 240,000 years of change, showing that vast freshwater lakes were fleeting as warming and drying reshaped the basin.

ByUSC Dornsife News September 14, 2026

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Key findings:

• USC Dornsife researchers studying the history of Utah’s Great Salt Lake identified two brief, deep-lake phases when the water was much fresher than now.
• Their analysis of core samples spanning the past 240,000 years shows that the most recent freshwater phase, which formed Lake Bonneville, lasted longer and was fresher than the earlier Little Valley lake phase.
• The researchers found that both lakes shrank and became salty as the regional climate warmed and dried, offering possible insights into Great Salt Lake’s future in the face of climate change.

The post appeared first on USC Dornsife.