> (...) leaving effectively a stone cast of a dinosaur foot, rather than a footprint that has somehow been flipped 180 degrees.
Yes, I also share that opinion. In fact, just by looking at the photo from Nature it seems like the cave's floor is comprised of upper strata that have cracked, broked off and fell down. If just so happened that the layer currently exposed has the imprint of some dinosaur footprints.
Perhaps other visitors didn't noticed it because the previous layer broke off recently?
Do archaeologists use the term 'footprint' differently than we use it colloquially, or is the title just wrong?
To me a footprint isn't shaped like my foot. It's something that my foot fits into.
The insight he shared with me was that caves don’t form in the softest or most permeable layers of rock. Instead they tend to form above the hardest layers - water wants to seek the lowest level and the only thing to stop it is a layer that’s hard, or impermeable. Whatever is above that is where the water does most of its work, even if there are softer layers further up.
So if I have it right, these dinosaur footprints were made upon a softer layer above very hard material that makes up the base of the cave, and the layer above those two was hard enough that it has so far resisted erosion, leaving effectively a stone cast of a dinosaur foot, rather than a footprint that has somehow been flipped 180 degrees.