Deep caves are a rich source of dinosaur prints for this paleontologist
Several deep caves in France are proving to be a surprising source of ancient tracks
Crawling through tight underground passages in southern France, paleontologist Jean-David Moreau and his colleagues have to descend 500 meters below the surface to reach the only known footprints of long-necked dinosaurs called sauropods ever found in a natural cave.
The team discovered the prints, left by behemoths related to Brachiosaurus, in Castelbouc Cave in December 2015 (SN: 2/21/18). But getting to the site might make even the most hardened field scientists balk. Wriggling through such dark, damp and cramped spaces every time they visit is challenging for elbows and knees, and even trickier when carrying delicate equipment such as cameras, lights and laser scanners.
It’s both physically exhausting and “not comfortable for someone claustrophobic,” with the researchers spending up to 12 hours underground each time, says Moreau, of the Université Bourgogne Franche-Comté in Dijon. It can be dangerous too, as some parts of the cave are periodically flooded, so accessing the deep chambers must be limited to periods of drought, he says.
Moreau has studied fossilized dinosaur footprints and plants for more than a decade in southern France’s Causses Basin, one of the richest areas for aboveground dinosaur tracks in Europe. When spelunkers chanced upon some underground prints in 2013, Moreau and his colleagues realized there could be lots of dinosaur prints within the region’s many deep, limestone caves. Footprints left in soft mud or sand hundred million years ago could have been turned to rock and forced underground over many eons.