Sediment records from dust blown into alpine lakes in southwest Colorado's San Juan Mountains over millennia indicates the sharp rise in dust deposits coincided with railroad, ranching and livestock activity in the middle of the last century, said geological sciences Assistant Professor Jason Neff, lead author of the study. The results have implications ranging from ecosystem alteration to human health, he said.

"From about 1860 to 1900, the dust deposition rates shot up so high that we initially thought there was a mistake in our data," said Neff. "But the evidence clearly shows the western U.S. had its own Dust Bowl beginning in the 1800s when the railroads went in and cattle and sheep were introduced into the rangelands."

The research that included CU-Boulder's Ashley Ballantyne, Lang Farmer and Corey Lawrence; Cornell University's Natalie Mahowald; the University of Arizona's Jessica Conroy and Jonathan Overpeck' Christopher Landry of the Center of Snow and Avalanche Studies in Silverton, Colo.; the University of Utah's Tom Painter and the U.S. Geological Survey's Richard Reynolds appears in the journal Nature Geoscience.