Evidence from ice cores for an ancient extreme solar particle event hitting Earth during a solar minimum
Abstract
The Sun erratically emits large amounts of energetic particles (SEPs) that react with the Earths atmospheric constituents and produce cosmogenic radionuclides, such as 14C, 10Be and 36Cl. To date, three extreme SEP events were unambiguously detected in 10Be and 36Cl records from ice cores (993/4 AD, 774/5 AD, 660 BC). These events were an order of magnitude larger than any known modern event, and may thus have dramatic consequences for our technological society if they occurred today. Hence, assessing the probability of occurrence of such extreme events is key to the development of robust risk assessments. Using new 10Be and 36Cl data from Greenland and Antarctic ice cores we provide evidence for a SEP event that occurred about 9,200 years ago, supported by 14C data from tree rings. Our multi-radionuclide dataset indicates that this ancient event was of similar magnitude as the one hitting Earth in 774/5 AD. Furthermore, the application of a novel ice core sampling method allowed us to collect highly resolved data that allows us to pinpoint when the event occurred within the 11-year solar cycle. These results show great promise for future detection of ancient events and the investigation of their relationship with solar activity levels.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFMSH55F1903P