In:
Nature Communications, Springer Science and Business Media LLC, Vol. 9, No. 1 ( 2018-09-06)
Kurzfassung:
Though tree-ring chronologies are annually resolved, their dating has never been independently validated at the global scale. Moreover, it is unknown if atmospheric radiocarbon enrichment events of cosmogenic origin leave spatiotemporally consistent fingerprints. Here we measure the 14 C content in 484 individual tree rings formed in the periods 770–780 and 990–1000 CE. Distinct 14 C excursions starting in the boreal summer of 774 and the boreal spring of 993 ensure the precise dating of 44 tree-ring records from five continents. We also identify a meridional decline of 11-year mean atmospheric radiocarbon concentrations across both hemispheres. Corroborated by historical eye-witness accounts of red auroras, our results suggest a global exposure to strong solar proton radiation. To improve understanding of the return frequency and intensity of past cosmic events, which is particularly important for assessing the potential threat of space weather on our society, further annually resolved 14 C measurements are needed.
Materialart:
Online-Ressource
ISSN:
2041-1723
DOI:
10.1038/s41467-018-06036-0
Sprache:
Englisch
Verlag:
Springer Science and Business Media LLC
Publikationsdatum:
2018
ZDB Id:
2553671-0
