Plagne site where sauropod dinosaur tracks were discovered. September 2009. Photo: CNRSFossil hunters in France have stumbled upon huge dinosaur footprints, said to be the biggest in the the world. The footprints were made about 150 million years ago by sauropods or long-necked herbivores in the Jura plateau of eastern France.
Discovered by Marie-Hélène Marcaud and Patrice Landry, two nature enthusiasts, the dinosaur footprints have been authenticated by Jean-Michel Mazin and Pierre Hantzpergue, both of the Université Claude Bernard Lyon 1.
According to the researchers' initial analyses, these dinosaur footprints are the largest found to date. Furthermore, the tracks spread over dozens and possibly even hundreds of meters. More significant digs will be conducted over the next few years and could result in the Plagne site being one of the largest known dinosaur sites on earth.
Plagne site. From left to right: the two discoverers, Marie-Hélène Marcaud and Patrice Landry, and the two researchers, Pierre Hantzpergue and Jean-Michel Mazin. September 2009.Marie-Hélène Marcaud, Patrice Landry and other members of the Société des naturalistes d'Oyonnax (SDNO) have been searching for dinosaur footprints for years. Convinced that the region had a rich paleontological heritage, they focused on potential sites and have been exploring them systematically. The SDNO is thus responsible for a number of discoveries. It was during one of these outings, on April 5, 2009, that Marie-Hélène Marcaud and Patrice Landry discovered the extraordinary footprints at Plagne. They contacted Jean-Michel Mazin and Pierre Hantzpergue, of the National Centre for Scientific Research (CNRS) .
The researchers authenticated the footprints based on morphological criteria and the sediment containing them. They believe that the Plagne site was along a route used by sauropod dinosaurs.
The dinosaur footprints in Plagne are circular depressions surrounded by a fold of limestone sediment. These depressions are very large, up to 1.50 m in total diameter, suggesting that the animals were larger than 40 tonnes and 25 meters in length. The limestone dates to the Tithonian stage (Upper Jurassic, -150MY), a period during which the area was covered by a warm and shallow sea. The discovery of these footprints shows that sauropods moved around during a phase of emersion of the area, when sea levels were low.
The Plagne site is exceptional, both for the size of the prints and the number of tracks which can be seen and those potentially left to discover. Geological studies and digs of such a large surface area require significant technical and human resources over several years.
