The recent discovery on Oct. 14, 2010, of exceptionally preserved plant and large mammal fossils at Zeigler Reservoir near Snowmass Village, Colorado provides a brief opportunity to study an amazingly well-preserved, sequence of high-elevation Ice Age ecosystems. In 18 days (Oct. 29 to Nov. 17, 2010), the Denver Museum of Nature & Science (DMNS) excavated more than 600 bones comprising parts of 8- 10 American mastodons, 4 Columbian mammoths, 4 Ice Age bison, 2 deer, 1 Jefferson?s ground sloth (the first record in Colorado and the highest altitude record in North America), multiple Tiger salamanders, and exceptionally preserved plant, insect and aquatic invertebrate fossils. As a whole, the site represents the first relatively complete sequence of lacustrine Pleistocene ecosystems at high elevation in the Rocky Mountains. A number of key research questions and opportunities have emerged: 1) What does this site tell us about high elevation Pleistocene climate and biota in the Ice Age Rockies? 2) What is the geochronology of the site? 3) What is the detailed history of lake in-filling? 4) What were the life histories of the site?s mammoths and mastodons? 5) Given the large number of specimens, can we undertake metapopulation analyses of the bison, mammoth, and mastodon? And 6) what is the relevance of this Rocky Mountain climate and biotic record to present-day issues of climate change? To answer these over-arching questions and other more specific questions, we have assembled a team of 32 scientists from 15 institutions organized into six groups to undertake a comprehensive multidisciplinary study of the Ziegler Reservoir fossil lake. These groups are: 1) regional and local geology; 2) stratigraphy; 3) geochronology; 4) fossil vertebrates; 5) fossil plants; and 6) fossil invertebrates. Using this approach, we are designing a plan to: 1) excavate the remaining fossil resources from the dam site in May-June, 2011, before the site is buried by planned dam construction in July-September; 2) implement a comprehensive scientific research plan to study and understand this site; 3) preserve and conserve the fossils from the site; and 4) to use the results of this discovery provide world-class educational opportunities to local, regional, national, and international audiences. DMNS is planning an comprehensive media and documentary plan for the 2011 excavation and DMNS educators will return to the Roaring Fork Valley in Spring 2011 to provide free education programs for K-12 students in all of the Roaring Fork Valley schools, including in-school assembly programs, distance learning programs, teacher professional development programs, and early childhood education resources available on This grant will partially fund the fieldwork portion of 2011 activities.

Project Report

The discovery of series of Late Pleistocene (130,000 to 50,000 years ago) ecosystems at Zeigler Reservoir near Snowmass Village, Colorado on Oct. 14, 2010, provided the brief opportunity to study an amazingly well-preserved sequence of high-elevation Ice Age ecosystems. The Denver Museum of Nature and Science (DMNS), in collaboration with government agencies and research institutions conducted 69 total days of fossil excavation. The effort involved >250 different people who were mostly volunteers, totally >3,000 days of work totaling >30,000 hours. The DMNS outreach strategy for the Snowmastodon Project excavation included daily and weekly updates from the dig site by dig scientists produced by DMNS staff using multi-media elements that were posted to the DMNS website and press room. Media was invited to the dig site to cover the story as events warranted, but the elements gathered for the web were repurposed and sent to media so reporters could cover the story each day without having to commit their own resources to it. The Museum used e-blasts, social media, and traditional media to drive traffic to the website, and traditional media relations to reach media. The effort generated strong results. Between October 2010 and May 2012, more than 630 newspaper, television, or radio stories were reported on the dig, including front page coverage in the science section of the New York Times, multiple front page stories in the Denver Post, radio stories for CBC, BBC, NPR, PBS News Hour, and stories in the Washington Post, the Huffington Post, the Los Angeles Times, USA Today, Associated Press,,, the Chicago Tribune, and PI’s Johnson and Miller also wrote a 200 page popular book on the discovery and excavation of the site. It has sold more than 5,000 copies. A book tour and talk series accompanying the dig has reached more than 6,000 people. A NOVA-National Geographic special was produced on the dig and was aired on PBS to 6.3 million people in February of 2012. Twelve thousand local elementary students (grades preK–6) experienced "Time Scene Investigation: Snowmass Village," a tech-savvy assembly program developed and delivered by the Museum focused on the dig. This interactive program allowed students to learn more about the Ice Age fossil discoveries through top-notch professional science educators, specimens from the Museum collections, props, and multimedia presentations. Four hundred local middle and high school students experienced "Mammoth of a Find: Live Broadcast from the Dig Site"—a 45-minute live broadcast connected Museum scientists via satellite for a two-way interactive experience. DMNS educators provided free education programs for K-12 students, including in-school assembly programs, distance learning programs, and teacher professional development programs, and early childhood education resources available on At the outset of the find, DMNS educators visited schools up and down the Roaring Fork Valley reaching 8,600 students. DMNS educator and scientists also hosted four, multi-day, Ice Age Festivals both in Snowmass and in Denver between Oct. 2010 and July 2011. These provided interpretive materials for the public and they were attended by 10,000 visitors. In collaboration with the Town of Snowmass Village, DMNS built the Ice Age Discovery Center, a 2,000-square-foot space in Snowmass Mall that features photos, videos, touch casts of mammoth and mastodon teeth, a wooden half-scale model of the discovery mammoth Snowy, plus related crafts and activities for children. The center is open daily from 10 a.m. to 5 p.m. through Sunday, September 19 and has been visited by more than 30,000 people. The project resulted in 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. 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 30 species of small animals including otters, muskrats, minks, rabbits, beavers, salamanders, frogs, lizards, snakes, fish and birds. The collection also included fossil logs representing at least three tree genera, hundreds of macro-fossil plants including many exceptionally preserved cones, and thousands of samples of microfossil (pollen) samples. All of the material is currently being conserved and preserved at the Denver Museum of Nature and Science and will soon be moved into the new, state-of-the-art Rocky Mountain Science Collections Center now under construction at DMNS. Presently, 42 scientists from 18 institutions are directly working on this new and truly unique collection of fossil plants and animals to understand the ecosystems of the high Rockies and climate change during the most recent warm period to the present day.

National Science Foundation (NSF)
Division of Earth Sciences (EAR)
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Lisa Boush
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Denver Museum of Nature and Science
United States
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