Hiker Steps into 280-Million-Year-Old Fossilized World in Italian Alps

“The very fine grain of the sediments, now petrified, has allowed the preservation of sometimes impressive details, such as the imprints of the fingertips and the belly skin of some animals,” Lorenzo Marchetti, sedimentology specialist at the Leibniz Institute for Research on Evolution and Biodiversity in Berlin, said in a translated statement. “The shape and size of the traces indicate a quality of preservation and a remarkable paleo-biodiversity, probably even higher than that observed in other deposits of the same geological age.”

Paleontologists discovered imprints of thin fingers, trails of long and curvy tails, and even ripples of waves on the shores of ancient lakes. The site remained completely concealed (and well-preserved) for millennia—until, that is, the current rapidly warming climate caused snow and ice to melt away. By 2023, enough of that cover had melted away for hiker Claudia Steffensen to notice some odd marks on the rocks.

“It was a very hot day last summer,” Steffensen told the Guardian, “and we wanted to escape the heat, so we went to the mountains. On our way back down, we had to walk very carefully along the path.” It was then she saw a rock that struck her has odd, as it “seemed more like a slab of cement. I then noticed these strange circular designs with wavy lines. I took a closer look and realized they were footprints.”

She snapped photos and sent them to Elio Della Ferrera, a nature photographer friend of hers who passed the images along to the Natural History Museum of Milan. From there, a team of researchers photographed and mapped hundreds of fossil traces at the site. they are still emerging on the vertical walls of the area and in the landslide accumulations below, sometimes as high as nearly 10,000 feet above sea level.

“Dinosaurs did not yet exist at that time, but the authors of the largest footprints found here must have been still considerable in size,” Cristiano Dal Sasso, paleontologist at the

Natural History Museum of Milan, said in a statement. He added that he believes the site contains examples of footprints from at least five difference animal species.

“The imprinted steps happened when the sandstones and clays were still soaked in water,” Ausonio Ronchi, specialists in sedimentology at the Department of Earth and Environmental Sciences at the University of Pavia, said in a statement. “The summer sun, drying those surfaces, hardened them to the point that the return of new water did not erase the footprints but, on the contrary, covered them with new clay forming a protective layer.”

The animal traces are joined by fossilized foliage, stem fragments, and seeds.

“The Orobic territory is proving to be a large open-air laboratory,” Massimo Merati, director of the park, said in a statement. Teams are now using drones and a helicopter to map the fossils on vertical walls and recover certain finds in the unstable landscape, respectively—especially as transporting boulders is impossible without the aircraft. The first stone that Steffensen stepped on, which contained the footprints of a prehistoric reptile, was part of the first recovery by air in October.

Stefano Rossi, official of the Superintendence of Archeology, Fine Arts, and Landscape for the region, said in a statement that the fossil deposit could become an “important case of study and transform itself into a training ground for researchers and students.”