A collaborative scientific endeavor involving researchers from the Helmholtz-Zentrum Dresden-Rossendorf, TUD Dresden University of Technology, and the Australian National University has identified a surprising concentration of beryllium-10, a scarce radionuclide generated in the atmosphere by cosmic ray interactions, within sediment cores retrieved from the depths of the Central and Northern Pacific Ocean.
Koll et al. report on the discovery of an anomaly in the beryllium-10 concentration profiles of several deep-ocean ferromanganese crusts (stars) from the Central and Northern Pacific during the Late Miocene. The major bottom (blue line) and surface (red line) ocean currents of the thermohaline circulation are indicated. Image credit: Koll et al., doi: 10.1038/s41467-024-55662-4.
Radionuclides are a classification of atomic nuclei, specifically isotopes, that undergo radioactive decay, transforming into different elements over elapsed time.
These isotopes are routinely employed in the chronological determination of both archaeological artifacts and geological formations, with radiocarbon dating standing as a prominent example of such methodologies.
“The seabed of Earth’s vast oceans constitutes one of the most intact geological records, preserving evidence of environmental conditions and transformations across millions of years, in the form of ferromanganese crusts,” stated Dr. Dominik Koll, the lead author and a researcher affiliated with the Australian National University and the Helmholtz-Zentrum Dresden-Rossendorf, along with his esteemed colleagues.
“The chronological assignment of these marine archives can be achieved through the analysis of fossils via biostratigraphy, by examining shifts in isotopic or elemental compositions, or by deciphering the imprints of Earth’s magnetic field reversals through magnetostratigraphy.”
“An additional widely utilized technique involves the dating of cosmogenic nuclides,” they further elaborated.
“The radionuclide known as beryllium-10 is perpetually generated within the upper atmosphere primarily through the process of cosmic ray spallation, predominantly acting upon nitrogen and oxygen atoms.”
“The atmospheric lifespan of beryllium-10 is estimated to be in the range of one to two years, during which it becomes adsorbed onto aerosols before precipitating out of the atmosphere.”
“Upon entering the marine environment, atmospheric beryllium-10 intermingles with the lithospheric stable isotope, beryllium-9. This latter isotope is chiefly introduced into the ocean via riverine discharge and atmospheric dust transported by rivers, resulting from the erosion of terrestrial mineral deposits.”
Dr. Koll and his fellow researchers identified a persistent anomaly in cosmogenic beryllium-10 within the analyzed samples from the Central and Northern Pacific regions.
Such an anomaly could potentially be attributed to significant alterations in oceanic current patterns or to extraterrestrial events that transpired during the Late Miocene epoch, an era approximately ten million years ago.
The implications of these findings suggest a potential for their application as a universal temporal marker, representing a significant stride forward in the precise dating of geological records extending over millions of years.
“For geological epochs spanning millions of years, such cosmogenic temporal markers are currently nonexistent,” Dr. Koll noted.
“Nevertheless, this particular beryllium anomaly possesses the capacity to function as such a marker.”
The research findings have been published in the esteemed journal Nature Communications.
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D. Koll et al. 2025. A cosmogenic 10Be anomaly during the late Miocene as an independent time marker for marine archives. Nat Commun 16, 866; doi: 10.1038/s41467-024-55662-4
