Question

How did scientists determine the age of the ocean floor

Answer 1

the layers of rocks, the ancient treasures that are at the bottom of the sea, how old the coral is. But I don't think they determined how old it is, how would the dinosaurs that lived in water swim or any drink water. I don't know if this helps but hopefully it does. Also scientist have made advanced tech that could help with the age determination of the ocean floor.

Answer 2

 Scientists can determine the age of the seafloor thanks to the changing magnetic field of our planet. Every once in a while the currents in the liquid core, which create the Earth's magnetic field, reverse themselves: This is called a geomagnetic reversal. 

hope this helps!