This sample of windblown dust, or loess, was deposited 23,000 years ago, at the height of the last glaciation, where sediments were washing out of glaciers. Dry winds picked up dust from these sediments and re-deposited it in a swath across what is now Nebraska, Iowa, and Illinois.
Provided by Iowa Department of Natural Resources and Schildberg Construction Company
Topic: Earth Science
Subtopic: Climate/Climate Change
Keywords: Loess, Glacial epoch, Paleoclimatology