Image Above: A dusty scene near Canyonlands in Utah. Dust in the West has increased by 500 percent since the 1800s. Credit: Jason C. Neff, University of Colorado at Boulder
The West has become 500 percent dustier in the past two centuries due to westward U.S. expansion and accompanying human activity beginning in the 1800s, according to a new study led by the University of Colorado at Boulder. 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 on the study. The results have implications ranging from ecosystem alteration to human health, he said.
The study indicates "dust fall" in the West over the past century was five to seven times heavier than at any time in the previous 5,000 years, said Neff, who is also a faculty member in CU-Boulder's Environmental Studies Program. While some fine-grained dust from Asia periodically falls on Colorado's San Juans, the abundance of larger-sized dust particles in the lake sediments there indicates most of the dust originated regionally in the Southwest, said the authors.