Stories tagged interglacial era

Oct
15
2011

Giant bison skull: its horns spanned 6 feet 4 inches. Behind stands Dr. Steve Holen, curator of archaeology at the Denver Museum of Nature & Science
Giant bison skull: its horns spanned 6 feet 4 inches. Behind stands Dr. Steve Holen, curator of archaeology at the Denver Museum of Nature & ScienceCourtesy Photo by Heather Rousseau ©Denver Museum of Nature and Science
The last talk I attended at the Geological Society of America (GSA) convention this past week was one of my favorites. It was an update of the Snowmastodon Project given by Kirk Johnson, chief curator at the Denver Museum of Nature and Science (DMNS). Just one year ago, a construction worker bulldozing for a dam-building project at the Zeigler Reservoir near Snowmass Village in Colorado unearthed a mammoth tusk. Paleontologists and archaeologists from the Denver museum were called in, and excavation of a small portion of the drained reservoir bottom soon got underway. The museum crew worked for just one month, until November 14, 2010, when snowfall halted the project. Then last spring scientists returned to the site and were allowed just 51 days to excavate the fossil deposits before the Snowmass Water and Sanitation District resumed their expansion work on the reservoir.

This time more research experts from the US, Canada, and England joined the dig along with a slew of interns and volunteers, totaling some 233 people working on the project. Over the next seven weeks excavation at the Zeigler Reservoir site progressed at a frantic pace. According to Johnson, anywhere from 15 to 90 diggers were on site each day digging out fossils from the ancient peat and mud deposits, from what once were the shores of a small glacial lake. Despite the short window of opportunity, the sheer number and diversity of fossils from the dig site has been truly remarkable.

American Mastodon: (Mammut americanum)
American Mastodon: (Mammut americanum)Courtesy Dantheman9758 at en.wikipedia
Of the nearly 5000 bones and skulls exhumed from the Snowmass fossil site, more than 60 percent were of mastodons (Mammut americanum) representing at least 30 individuals in various stages of life. The other 40 percent of the fauna included mammoths (Mammuthus columbi), camels, horses, giant bison (Bison latifrons) and ground sloths (Megalonyx jeffersonii), otters, muskrats, minks, bats voles, chipmunks, beavers, bats, rabbits, mice, salamanders, frogs, lizards, snakes, fish, and birds, and iridescent beetles. No large carnivore remains were found in the deposits, and human remains were absent as well, although archaeological techniques were used during the dig just in case any were uncovered.

Flora from the prehistoric tundra environment included pollen, green leaves and cones, and tree logs, some with their bark still intact.

So far, age estimates for the deposits range between 43, 000 to 130,000 years old although further dating tests should narrow that down.

The talk included several photos of what Johnson termed “Flintstone moments”, i.e. shots of field workers posing with massive mammoth or mastodon femurs or tibia. And Johnson marveled at the incredible state of preservation of many of the fossils displayed. Some of the bones, he said, still emitted a very strong funk.

In terms of sheer number of bones and ecological data, Snowmastodon ranks up there as probably one of the best high altitude Ice Age ecology sites in the world, and certainly the best mastodon fossil site. A team of researchers at the DMNS lab will spend the next year and a half cleaning, cataloging, and analyzing all the fossils found at the Snowmass dig site, water was to be reintroduced into the reservoir on Oct. 13. Despite the loss of the site, the field crew did a tremendous job in the time they were given to excavate the fossil-rich site. And Kirk Johnson didn’t hide his excitement. In closing his talk, he said “It was one hell of a year!”

FURTHER INFO
The Snowmastodon Project website
Photo set on Flcker