There seems to be too much of a radioactive element in rocks deep in the Pacific Ocean – how did it get there 10 million years ago?

Earth must have experienced something exceptional 10 million years ago. Our study of rock samples from the floor of the Pacific Ocean has found a strange increase in the radioactive isotope beryllium

A strange radioactive 'blip' has been detected deep beneath the Pacific Ocean. Analyzing several thin layers of seafloor crust, scientists in Germany have identified a sudden surge in the radioactive isotope Beryllium-10 sometime between 9–12 million years ago.