Development & Aid, Environment, Tierramerica

Following the Dinosaur Tracks

LA PAZ, Jun 13 2005 (IPS) - A cement quarry in southern Bolivia reveals secrets of 294 species of animals that disappeared 65 million years ago.

A vast bed of dinosaur tracks, known as Cal Orko, on an 80-meter rock face. - Waldo Maluenda, Roxana Acosta, Sucre Municipal Tourism Directorate

A vast bed of dinosaur tracks, known as Cal Orko, on an 80-meter rock face. - Waldo Maluenda, Roxana Acosta, Sucre Municipal Tourism Directorate

The more than 5,000 dinosaur footprints discovered in Cal Orko, in southern Bolivia, have forced a reconstruction of the planet's history and a correction of scientific errors made about these gigantic animals that dominated the landscape until some 65 million years ago, when they disappeared from the face of the Earth.

That is the main conclusion of the international scientific team led by Swiss paleontologist Christian Meyer, director of the Basil Natural History Museum and dean of that Swiss city university's paleontology department, which in 1998 certified the existence of the dinosaur tracks three km from Sucre, Bolivia.

The paleontology site, discovered in a quarry of a cement factory, is ''far and away the largest site of dinosaur tracks found so far,'' said Meyer.

The discovery is an enormous contribution to humanity and to science, revealing data heretofore unknown about the final period of the Cretaceous period and the beginning of the Tertiary period, some 66 million years ago, ''documenting the high diversity of dinosaurs better than any other site in the world,'' said the expert, who has been traveling the world for more than 15 years searching for and uncovering dinosaur tracks.

Before Cal Orko, the biggest known site was Khjoda-Pil-ata, in Turkmenistan, and there are other large sites in Portugal, Britain, Spain and Switzerland. But the Bolivian site ''is several times larger than any of them,'' Meyer said. At each of the other sites, scientists had found up to 220 tracks from two species.

The immense Bolivian site is the rock face of an outcropping on a slant of 73 degrees, 80 meters high and 1.2 km long. There are tracks of 294 different dinosaurs made during the second half of the Cretaceous period.

The first news of the Bolivian paleontological site dates back to 1985, but it was from 1994 to 1998 that a team of 25 paleontologists — from Bolivia, Europe and United States — studied and certified the bed, under Meyer's direction.

During the Cretaceous, Cal Orko was part of an immense shallow lake. In the Tertiary, when the Andes Mountains were formed, the movement of the tectonic plates pushed the former lake bed vertically. Not far from this site, eight others have been found in recent years and are being studied.

Meyer, vice-president of the European Association of Paleontologists, explained to Tierramérica that before the Bolivian discovery, it was believed that dinosaurs began disappearing gradually from the Jurassic to the Cretaceous period, and that at the end of the latter, the few surviving species died off suddenly en masse.

But ''the 'dino-diversity' is very great in Orko and amends the debate about the gradual decline until the end of the Cretaceous. We have discovered that in this latest period, when massive extinction occurred, the existence of the dinosaurs was vast and much more varied than was believed until now. The whole collection is right there,'' said Meyer.

One of the discoveries that astonished him were the footprints of the anchylosaurus, a quadruped herbivore that was not believed to have lived in South America. This animal was represented as a sort of giant, awkward armadillo weighing eight tons, but ''the study of its tracks in Orko describes for us a saurus much taller and thinner, with longer and lighter legs,'' he said.

Now it will be necessary to reconstruct the models of skeletons on exhibit in the museums of the world and rewrite the descriptions, said the scientist.

Also found in Cal Orko were traces of the herbivore sauropods, including the gigantic titanosaurus, measuring 25 meters tall and with footprints 70 cm in diameter; and the big predators like the theropods, with 35-cm footprints.

Fossils of turtles, crocodiles, fish and seaweed from the Later Cretaceous were found, allowing the paleontologists to carry out more rigorous studies of the period. Previously data about life at that time was relatively scarce.

It is thought that dinosaurs arrived in South America, from North America, towards the end of the Jurassic (around 145 million years ago), or, according to another theory, they arrived from Africa before the continents were separated 235 million years ago.

To contribute to preserving the site, a Cretaceous Park is slated to open in March 2006. Replicas of different dinosaur species will welcome visitors to a museum with audiovisual exhibits, transporting them — at least in their imaginations — to prehistoric time.

The park project organizers announced that they are working on protecting the outcropping, but Meyer warns that ''before building the park it is essential to shore up the wall, because there is an active tectonic fault in the middle of it. If it isn't stabilized, it will collapse and the future park will be left without its major attraction, and humanity will lose part of the planet's history.''

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