Jan 23, 2011

Ice age graveyard reveals its secrets

The fossilised remains, which were discovered in sediment at the bottom of a drained reservoir in the Rocky Mountains, Colorado, are thought to be one of the largest collection of animals from the last ice age to be found in one place and it is already providing scientists with new insights into the prehistoric environment.

Contractors preparing the ground for the construction of a new dam at the reservoir near Snowmass Village, which is part of the Aspen ski resort, uncovered the bones of a mammoth and now more than 600 bones have been recovered from beneath the lake bed before heavy snow halted the excavation.

Palaeontologists leading the dig found the remains of four Columbian mammoths; 10 American mastodons, a distant relation of the mammoth and elephant; four ice age bison, which were twice the size of modern bison; a species of ice age deer; and a Jefferson's ground sloth and a tiger salamander.

They expect to find more fossils when the return to the site when the snow melts in the spring.

Researchers, including experts at the Royal Holloway University of London, are now attempting to piece together how the animals came to be buried in one place and what the ice age landscape would have looked like at the time.

"It is an amazing site and is very unusual," said Dr Kirk Johnson, chief curator and vice president of research and collections at the Denver Museum of Nature and Science who led the excavation. "It is a true treasure trove of ice age fossils.

"Many of the fossils are pristine as they have been very well preserved. Some of the bones we recovered are still white while we are finding leaves that are still green and tree branches with the bark still on.

The first mammoth was discovered at the end of October when a bulldozer struck some of the ice age mammals' bones during work to expand the Ziegler Reservoir, which sits on a plateau at 8,870 feet in the Colorado Rocky Mountains.

Palaeontologists from Denver Museum of Nature and Science spent two weeks excavating a one acre wide area, unearthing more than 25 different animals from seven different species within a two-week period.

Among the most dramatic fossils to be found was the skull of an ice age bison, Bison latifrons, with three foot long horns. Weighing nearly 18 stone, the skull measures almost eight feet across from the tip of each horn when it was pieced together.

They also found more than 15 tusks including massive seven foot long mastodon tusks, bones of an as yet unknown species of ice age deer, the remains of a Jefferson's ground sloth, an extinct plant eater that grew to be the size of an ox.

They also discovered the remains of trees that bore teeth marks from an ice age beaver. Other bones bore teeth marks, suggesting some of the animals may have been killed by predators, although the palaeontologists have yet to find any remains of predators.

The animals are thought to have lived between 150,000 and 50,000 years ago when much of northern Europe and North America was covered in glaciers from the last ice age.

Read more at The Telegraph

No comments:

Post a Comment