Media release

From: The Australian National University

Rare radioactive elements discovered in Pacific Ocean could unlock secrets of Earth’s evolutionary past

Beryllium-10, a rare radioactive isotope produced by cosmic rays in the atmosphere, provides valuable insights into the Earth's geological history. Radionuclides are types of atomic nuclei (isotopes) that decay into other elements over time. They are used to date archaeological and geological samples, with radiocarbon dating being one of the most well-known methods.

The research team from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), in collaboration with the TUD Dresden University of Technology and The Australian National University (ANU), discovered an ‘unexpected’ accumulation of this isotope in samples taken from the bottom of the Pacific Ocean.

Such an anomaly may be attributed to shifts in ocean currents or astrophysical events that occurred approximately 10 million years ago. The findings hold the potential to serve as a global time marker, representing a promising advancement in the dating of geological archives spanning millions of years.

“For periods spanning millions of years, such cosmogenic time markers do not yet exist. However, this beryllium anomaly has the potential to serve as such a marker,” lead author Dr Dominik Koll, from ANU, said.

The team presents its results in the scientific journal Nature Communications (DOI: 10.1038/s41467-024-55662-4).