Snowmastodon: Oct 14, 2010, fossils were discovered by accident during the construction of a reservoir to supply Snowmass ski village with water.

The Snowmastodon site, or ‘Ziegler reservoir fossil site’ brought in crews from the museum of nature & science along with construction crews. Nearing completion, in one year, 36,000 vertebrate fossils (including mammoths, mastodons, ground sloths, horses, camels and deer), were discovered. Approximately 3,000 of them were mastodons. The site holds the record for the most mastodons preserved in a single location. Including the largest mastodon ever found.

By the time excavation completed, more than 300 people, from at least 19 institutions removed 8000 cubic meters of sediment. The village even announced a Mammoth music fest. With chilli, music and arts.

It was an amazing find, not just because of the location. The scientists and builders had also recovered at least 52 different late pleistocene vertebrate animals. It included a camel, horse, sloth and smaller vertebrates. In a short span of time, the speed of the project was unlike anything ever completed.

The Ziegler reservoir fossil site is unique because it is one of the only site from the sangamonian stage, at higher elevations. It also preserved multiple alpine ecosystems stacked on top. Scientists had been looking for plant bio-geography of the Rocky Mountains during the last interglacial period. Some of the beetles were still iridescent, and large logs were still preserved. They got what they needed.

Vertebrate Fauna:
The 52 macro and micro vertebrate taxa represent a diverse assemblage of fauna included to the rancholabrean north American land mammal age. Smaller vertebrate species included: trout, frog, salamander, snake, lizard, duck, goose, pheasant, crane, finch, shrew, river otter, bear, coyote, rabbit, chipmunk, squirrel, beaver, mice and other small rodents. The most abundant species found was the tiger salamander.

There were 7 megafauna taxa. These taxa include:
▪ Columbian mammoth (mammuthus columbi) – Four individuals, including the first fossil recovered from the site.
▪ American mastodon (mammut americanum) – This is the largest site for mastodons in the world with at least 35 individuals present.
▪ Jefferson’s ground sloth (megalonyx jeffersonii) – This marks the first time this species has been found in Colorado.
▪ Giant bison (bison latifrons) – The Ziegler reservoir is one of only three sites to produce multiple individuals of B. latifrons and the highest known elevation for this species.
▪ Deer – At least 2 individuals of indeterminate species.
▪ Camelops – A single tooth belonging to the extinct camel genus, was found in lake-center deposits. It is also the highest known elevation for this genus.
▪ Horse – A single foot bone from an indeterminate species of Equus.

Invertebrate Fauna:

Spanning from intervals of 125,000 to 77,000 years ago. A total of 99 taxa of insect were identified from samples. These fossils included the oldest known pleistocene high elevation insect faunas from the rocky mountains. The fossil assemblages were dominated by beetles, ants, midges, and caddisflies. They were used in part, to document the climatic oscillations during the time.

Fossil Flora:
99 taxa of plant macrofossils, including seeds, leaves, needles, cones, twigs and wood were identified. Ranging in size from small stems, to logs greater than 50 cm in diameter. Species of fir, douglas fir, spruce, pine, sagebrush, spruce, pine, oak, juniper, as well as herbaceous and aquatic plants were represented. Most of the wood fossils came from the “beach” horizon at the lake margin.

Now that the site is covered with water, scientists are not concerned. Being underwater helps preserve the fossils and the reservoir can be drained if ever the need arises for additional excavations and research.

Bibliography: Johnson, Kirk; Miller, Ian (March 22, 2012). Digging Snowmastodon: Discovering an Ice Age World in the Colorado Rockies (1st ed.). People’s Press. p. 144. ISBN978-1936905065.

Significant Fossil Find Unearthed in Colorado by Gould Construction”. CU Engineering, University of Colorado. Archived from the original on January 20, 2012. Retrieved July 8, 2011.

Urquhart, Janet. “Museum reaches agreements to resume Snowmass fossil dig”. Aspen Times. Retrieved 11 May 2011.

“PBS Television Series Nova: Discovering Snowmastodon”.

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