April 23rd, 2020 : Titanosauriforms

[xoxoxoBruce]

With a name like Titanosauriforms you better be tough or you’ll be getting swirlies in the boys room.
No problem, at 50+ tons they were some of the largest terrestrial animals to ever exist.

UNDER NORMAL CIRCUMSTANCES, HUNDREDS OF people pass through Castelbouc Cave in the south of France each year, many seeking to become more experienced cavers by training in the labyrinthine passageways under the surface. Little do they know that they’ve long been exploring—literally—among the footsteps of giants.

Probably because the footsteps were on the ceiling.

More than 160 million years ago, stone that now forms the roof of the cave was a part of a route taken by titanosauriforms, some of the largest dinosaurs that lived. One day, a group of the animals trekked across a clay embankment abutting an inland sea, the bed of which now underlies much of France. The dinosaurs’ depressions on the ground remained, and over time, the area was buried under millions of years of sediment. As the land rose and sea level dropped, erosion eventually carved the limestone cave system, including a passage that ran directly under the original dinosaur impressions.

France’s Gorges du Tarn is a steep canyon perforated with karst cave networks.

“The tracks we see on the roof are not footprints,” Moreau says. “They are counterprints.” That is, they are convex structures rather than depressions, like a plaster cast of a footprint, except in the stone and only visible from beneath.

link