70,000 years ago: A young, female Columbian mammoth, grazing the shores of a small peat bog high in the Rocky Mountains, meets a terrible fate. Whether driven by some fearsome Pleistocene predator, or simply seeking water or food, she gets trapped in a sticky, cold mix of mud and rotting plants. Now the carnivores descend. Some combination of bears, wolves, foxes, minks, and all manner of small rodents make a meal of her, devouring the carcass and chewing her bones. As the weeks go by, the bog claims what’s left of the young mammoth, enveloping her remains in an Ice Age tomb.
Oct. 14, 2010: Late on a chilly afternoon just on the outskirts of the Town of Snowmass Village, Jesse Steele, a third-generation bulldozer driver, plows his 18-ton machine through the bones of the same young, female Columbian mammoth. His first clues that he’s exhumed an amazing Ice Age fossil are two rib bones that flip over the front of his bulldozer blade. Jesse jumps out and finds parts and pieces of what turns out to be most of an exquisitely preserved skeleton. He calls over the construction team. Jesse and his coworkers make two fateful decisions: First, they stop excavation and rope off the find, and second, they call the Denver Museum of Nature and Science (DMNS). Little did they know that those decisions would set in motion the largest fossil excavation in Colorado’s history and lead to the discovery of one of the world’s most important Ice Age fossil sites.
Nov. 1, 2010 to July 4, 2011: In an unprecedented collaboration among DMNS, local and national government agencies led by the United States Geological Survey, more than 18 research institutions, and a very willing and excited Town of Snowmass Village, a lost and forgotten Ice Age world was brought to light. A total of 69 days of fossil excavation removed more than 8 tons of dirt by hand. The hard work involved more than 300 different people, mostly volunteers, and totaled more than 3,000 days of work and 30,000 hours. This colossal effort led to results that were nothing short of monumental. The teams unearthed an unparalleled collection of fossil plants and animals from a series of stacked and exquisitely preserved ecosystems that existed between 130,000 and 50,000 years ago, including the 70,000 year mark that preserved the discovery mammoth, later named Snowy. In particular, the excavation discovered approximately 5,426 large mammal bones from extinct Late Pleistocene animals including American Mastodons, Columbian Mammoths, Jefferson’s Ground Sloths and extinct Ice Age bison, horse, deer and camels. Thousands of small bones were screened from the matrix at the site, which led to the discovery of more than 50 species of small animals including otters, muskrats, minks, rabbits, beavers, salamanders, frogs, lizards, snakes, fish and birds. The discovery also included huge fossil logs representing at least three tree species, hundreds of macro-fossil plants, including many exceptionally preserved conifer cones, and thousands of samples of pollen grains.
July 4, 2015 to Dec. 2014: Continuing the spirit of collaboration that was the hallmark of the Snowmastodon Project, more than 50 scientists from around the world worked to crunch the fossil data. At the end of 2014, a collection of 14 highly detailed scientific papers covering many aspects of the discovery appeared in the journal Quaternary Research. All the scientific revelations taken together tell a story that directly helps us understand the fate ecosystems of the high Rockies. Because the site existed and preserved fossils from the last glacial–interglacial–glacial sequence the present day, it gives us clues into Colorado’s future. Importantly, it shows that high-elevation ecosystems in the Rocky Mountains are climatically sensitive and respond rapidly and significantly to changing environments. Regionally, it shows that the climatic response at high elevation in the mid-latitudes of North America to global climate change has both expected and unexpected results. In particular, it demonstrates the importance and strength of known hemisphere-scale connections (for example, as sea water conditions change in the North Atlantic, climate changes in Colorado) while further underpinning the fact that regions, particularly those in the mountains, respond differently to changing environmental pressures.
2015 and Beyond: Scientific research continues on the amazing fossils found near the Town of Snowmass Village. Just a taste of the work includes: CT scanning the inner ears of the Jefferson’s Ground Sloth skulls to understand aspects of extinct sloth behavior; a compilation of fossil charcoal to understand the fire history at the site to investigate whether or not it is tied to climate change; a tree-ring-by-tree-ring chemical analysis of the fossil wood to look at year-to-year changes in climate more than 100,000 years ago; studies on fossil proteins from bison and mastodons; and continued work understanding the birth, life and death of the mastodons from growth lines in their tusks. Beyond the science, a non-profit organization called Snowmass Discovery has been formed with the goal of building a state-of-the-art facility in the Town of Snowmass Village that presents the science behind the discovery. While the future is notoriously hard to predict, the Snowmastodon Project has always come with a bit of luck. We hope that the next five years will bring new opportunities for science, and new opportunities to share these amazing stories with the world.
Selected further reading and watching:
- Summary article from the Quaternary Research volume: Miller, I.M., et al. (2014). A high-elevation, multi-proxy biotic and environmental record of MIS 6-4 from the Ziegler Reservoir fossil site, Snowmass Village, Colorado, USA. Quaternary Research 82 (3), p. 618–634.
- Johnson, K. R. and Miller, I. M., 2012. Digging Snowmastodon: Discovering an Ice Age World in the Colorado Rockies: Aspen, CO, Denver Museum of Nature and Science and People’s Press, 144 p.
- NOVA: Ice Age Death Trap. http://www.pbs.org/wgbh/nova/earth/ice-age-death-trap.html
- Johnson, Kirk “Pleistocene Treasures, at a Breakneck Pace.” New York Times [New York] July 5, 2011, D1.
- The Snowmastodon Project website: /science/the-snowmastodon-project/