Where did all the earth and rock come from to cover up the Cretaceous layer all over the planet? :-P
Plate tectonics? Subduction?
I know you are being facetious, but the earth has tons of cosmic stuff fall onto it annually. Its like when you leave your car parked for a couple of weeks and it gets dirty. Except, this happens over millions of years.
Plus plate tectonics and volcanism.
The earth is a dynamic thing.
Geological shift happens.
Your question is a good question.
They can just go to places like the Grand Canyon if they want to see old rock layers.
Google AI search results: They are about 1.84 billion years old. The youngest rock layers, forming the canyon’s rim, are about 270 million years old
https://en.wikipedia.org/wiki/Geology_of_the_Grand_Canyon_area
The commies have plenty of Cretaceous rocks. They don’t have to drill so deep. I guess they have NGO’s too and waste lots of money.
Google: Cretaceous rocks are found where in china
FTA: the team is aiming to pass through more than 10 layers of continental rock and reach the Cretaceous geological system, dating back 145 million years.