A team of scientists from Helmholtz Senturm Dresden Rossendorf, Tad Dresden Institute of Technology, and the Australian National University have discovered an “unexpected” accumulation of Beryllium-10 from the bottom of the central and North Pacific Oceans.
Col et al. Report on the discovery of anomalies in the beryllium-10 concentration profiles of several deep-sea ferromanganese crusts (stars) from the late Miocene central and North Pacific Oceans. The main bottom (blue line) and surface (red line) ocean currents of the thermal halin circulation are shown. Image credit: Koll et al., doi: 10.1038/s41467-024-55662-4.
Radionuclides are types of nuclei (isotopes) that decay into other elements over time.
They are used to date archaeological and geological samples, and radiocarbon dating is one of the best-known methods.
“The major ocean floors on Earth show one of the most pristine geological archives documenting environmental conditions and changes over millions of years, the ferromanganese crust,” Zentrum Dresden-Rossendorf and his colleagues.
“Dating these marine archives can be achieved through fossils through changes in biostratigraphy, isotope, or elemental composition. Alternatively, we can analyze the imprinted changes in the Earth's magnetic field due to magnetic stratigraphy. Masu.”
“Another commonly employed technique is dating space-forming nuclides,” they added.
“The radionuclide Beryllium-10 is continuously produced in the upper atmosphere, primarily through cosmic ray spallation for nitrogen and oxygen.”
“The residence time of Beryllium-10 in the atmosphere is about 1-2 years for it to adhere to the aerosol and precipitate.”
“In the ocean, atmospheric beryllium-10 mixes with the stable beryllium-9 of the lithosphere, which is transported to the ocean by river runoff and river dust, primarily after erosion of terrestrial minerals.”
Dr. Koll and co-authors have discovered long-term cosmicogenic beryllium-10 anomalies in central and North Pacific samples.
Such anomalies can be attributed to changes in ocean currents or astrophysical events that occurred during the late Miocene era around 10 million years ago.
The findings have the potential to serve as a global time marker for promising advances in dating geological archives over millions of years.
“For a period of millions of years, such space-forming time markers still do not exist,” Dr. Koll said.
“However, this beryllium abnormality can act as such a marker.”
result It will be displayed in the journal Natural Communication.
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D. Koll et al. 2025. Cosmic genome 10It becomes abnormal in the late Miocene as an independent time marker for marine archives. Nut commune 16, 866; doi:10.1038/s41467-024-55662-4
Source: www.sci.news
