Unexpected ocean find rewrites Earth's geological timeline
Scientists have identified an anomaly linked to the rise in beryllium-10 levels in ocean sediments on the Pacific Ocean floor. According to the portal Interesting Engineering, this finding could enhance the dating of Earth's geological history. The discovery may be associated with an event from 10 million years ago.
Researchers from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), TUD Dresden University of Technology, and the Australian National University have observed an unexpected increase in beryllium-10 levels in samples from the Pacific seabed. This discovery could become a global time marker, aiding in the synchronisation of geological records over millions of years.
Invaluable tool for reconstructing Earth's history
Beryllium-10 is a rare radioactive isotope that forms when cosmic rays collide with oxygen and nitrogen in the atmosphere. With time, it falls to Earth and accumulates in ocean sediments. Due to its half-life of 1.4 million years, this isotope enables us to trace events up to 10 million years ago. Interesting Engineering notes that it "provides valuable insights into the Earth's geological history."
The team, led by Dr. Dominik Koll, analysed ferromanganese crusts from the Pacific seabed, which capture a record of environmental changes. By employing accelerator mass spectrometry, researchers precisely measured the beryllium-10 content in the samples.
Scientists did not expect such a discovery
The research findings were unexpected. "At around 10 million years, we found almost twice as much beryllium-10 as we had anticipated. We had stumbled upon a previously undiscovered anomaly," reported Dr. Koll. The team ruled out contamination by examining additional samples from various locations, all showing the same pattern.
Scientists are considering two hypotheses to explain this anomaly. One posits changes in ocean currents near Antarctica, which may have affected the uneven distribution of beryllium-10. Alternatively, the intensity of cosmic radiation might have increased due to a nearby supernova.
If the anomaly is global, the astrophysical hypothesis gains importance. Otherwise, changes in ocean circulation are more plausible. This discovery could transform geological dating, aiding in the synchronisation of different geological archives.
