Snowmastodon site
Crews from the Denver Museum, U.S. Geological Survey, and several other institutions work alongside bulldozers for two weeks in order to salvage the increasing number of fossils being unearthed.
[2] By the time excavation had been completed, the team consisting of more than 250 volunteers and 40 project scientists removed approximately 8000 cubic meters of sediment.
[2][1] Thousands of fossils were collected along with stratigraphic, geochronologic, palynologic, paleoentomologic, and paleobotanic data that was subsequently used to reconstruct the paleoecosystem at ancient Lake Ziegler.
[15][17] A small excavation crew from the museum remained at the site, in the event further discoveries were made in the course of the dam construction.
[1][21] The fossil flora offer unprecedented insights into plant biogeography of the Rocky Mountains during the last interglacial period.
Fossil sedge and willow leaves were still green, conifer cones were still intact, and large driftwood logs were preserved.
The lake basin was formed when a glacier flowing down Snowmass Creek Valley became thick enough to overtop the adjacent ridgeline.
[24] After Doug Ziegler and his family purchased the land that now contains the Ziegler Reservoir, they commissioned the construction of a small earthen dam in 1961 to block the meadow drainage and form a shallow, private lake that persisted until the Snowmass Water and Sanitation District bought the water rights in 2010.
[25] In situ cosmogenic beryllium and aluminum from a boulder that was part of the bounding moraine yielded an age of approximately 140,000 years old.
[25] Uranium-series dating of vertebrate fossils confirmed the age range of 45,000-140,000 years; however, the extremely low uranium concentrations limited the utility of that method.
[20] These taxa represent a diverse assemblage of fauna belonging to the Rancholabrean North American Land Mammal Age.
[20] The smaller vertebrate species include: trout, frog, salamander, snake, lizard, duck, goose, pheasant, crane, finch, shrew, river otter, bear, coyote, rabbit, chipmunk, squirrel, beaver, mice and other small rodents.
[27] The fossil assemblages were dominated by beetles, ants, midges, and caddisflies, which were used to document the climatic oscillations during the time represented by the samples.
Approximately 99 taxa of plant macrofossil, including seeds, leaves, needles, cones, twigs and wood were identified.
[29] Over 300 specimens of fossil wood were collected ranging in size from small stems to logs greater than 50 cm in diameter and more than 10 m in length.
