Scientists discover a unique 10 million-year-old find at the bottom of the Pacific Ocean: what is it about?
Researchers have recorded a significant increase in the level of beryllium-10 (¹⁰Be) in samples of the Pacific Ocean seabed. This discovery could become an important tool for studying the Earth's past.
According to scientists, beryllium-10 can serve as a kind of "global time marker", helping to more accurately synchronize geological records spanning millions of years. For example, archaeological finds such as bones or wood residues can be more accurately dated using this method. This is reported by Interesting Engineering.
Physicist Dominik Koll of the Helmholtz Center Dresden-Rossendorf (HZDR) explained that radiocarbon analysis is limited to objects up to 50,000 years old. For older samples, it is necessary to use isotopes such as cosmogenic beryllium-10.
This rare radioactive isotope is formed in the upper atmosphere when cosmic rays interact with oxygen and nitrogen. Subsequently, beryllium-10 falls out in precipitation and accumulates in ocean sediments. Due to its half-life of 1.4 million years, it allows us to trace events from tens of millions of years ago.
Koll's team analyzed iron-manganese crusts recovered from several kilometers deep in the Pacific Ocean. These formations contain traces of environmental changes that have accumulated over millions of years.
The results of the study were unexpected.
"At about the depth corresponding to 10 million years, we recorded almost twice as much 10Be as expected. This indicates a previously unknown anomaly," Koll said.
What could have caused the surge in beryllium-10
Scientists are considering two possible explanations:
- Changes in ocean currents. About 10-12 million years ago, the circulation of water masses near Antarctica underwent significant changes, which could have led to an uneven distribution of 10Be across the planet and its local accumulation in the Pacific Ocean.
- Astrophysical event. The increased intensity of cosmic radiation at that time could have increased the production of beryllium-10 in the Earth's atmosphere.
Scientists are planning further research to determine the true cause. If similar anomalies are found throughout the Earth, this will confirm the astrophysical hypothesis. If their localization is limited, the main factor is likely to be the change in ocean circulation.
Regardless of the origin of this anomaly, it can significantly affect geological dating methods.
"Today, there are no cosmogenic time markers for periods spanning millions of years. However, the phenomenon we have discovered could change the situation," Koll summarized.
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