While expanding a reservoir in Snowmass Village, Colorado, construction workers stumbled upon a big bone. And then another, and another, and another.
Realizing they had found something special, the workers called in the Denver Museum of Nature&Science and the scientists quickly agreed that this was no ordinary boneyard. Work on the reservoir halted as dozens of volunteers from around the country helped excavate the site. In a few weeks of excavating, the scientists and volunteers of the Snowmastodon Project uncovered an entire Pleistocene ecosystem, including fossils of giant ground sloths, long-horned bison, North American camels, mammoths, mastodons, insects and ancient plants.
The dig site was as renowned for its geologically unique setting as the community around it is known for skiing. The setting, an ancient alpine lake on top of a terrestrial high-point, meant that it once attracted animals as a watering hole, but was able to evade the destructive processes associated with glaciations. Snowmass Village sits at 2,705 meters of elevation, making this alpine site one of the highest Pleistocene fossil localities ever discovered.
The sediments under the reservoir also preserve a nearly continuous record of change from 140,000 to 55,000 years ago, including a span of time starting about 130,000 years ago as a glacial period began to wane.