Posted on behalf of Patricio Segura.

In Chile’s Atacama Desert, the driest in the world, a team of researchers from institutions in Chile, Brazil and the United States has found more than 80 exquisitely preserved whale fossils.

The finds, made near the northern city of Caldera, are just the first from what promises to be one of the largest and most diverse paleontological troves of its kind. First indications are that the fossils are 7 million years old.

The site is remarkable for the concentration and quality of specimens, and for their diversity, says team member Nicholas Pyenson, curator of fossil marine mammals at the Smithsonian Institution in Washington DC. The fossils include adult and juvenile baleen whales, a walrus-whale, an extinct species of sperm whale, and possibly a seal or sealion.

As well as pinning down the fossils’ age, the team excavating the site is trying to work out why it contains so many whales, with a view to determining how they died.

The researchers are also studying the site’s geology, says Pyenson. “We wish to understand the environment in which the remains of these marine mammals were preserved, and we also wish to understand the processes of disarticulation and decay that has preserved their bones,” he says.

In 2010 a construction company working on a highway, under the supervision of researchers from the Palaeontological Museum of Caldera, found a high concentration of baleen whale skeletons. Amazed by the findings, researchers began excavating the site, which is about 20 m wide and 240 m long.

The road builder’s schedule means that palaeontological work must be completed by December 2011

Pyenson and his colleagues are working to document the fossils while they are still in the ground, using scanners to take images from which three-dimensional digital models can be constructed. He hopes that online digital images of the fossil whales, in the conditions in which they were found in the field, will be made available, and that other museums will be able to make replicas of the skeletons.

Even though the road builders will soon get the original site back, the researchers believe they will find more fossils nearby.

Image courtesy of Felipe Infante/Chilean National Museum of Natural History.