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Rapid increase in cosmogenic C-14 in AD 775 measured in New Zealand kauri trees indicates short-lived increase in C-14 production spanning both hemispheres

  • D. Guettler
  • Florian Adolphi
  • J. Beer
  • N. Bleicher
  • G. Boswijk
  • M. Christl
  • A. Hogg
  • J. Palmer
  • C. Vockenhuber
  • L. Wacker
  • J. Wunder
Publishing year: 2015
Language: English
Pages: 290-297
Publication/Series: Earth and Planetary Science Letters
Volume: 411
Document type: Journal article
Publisher: Elsevier

Abstract english

In 2012, Miyake et al. reported a sudden and strong increase of the atmospheric radiocarbon (C-14) content in Japanese cedar trees of 1.2% between AD 774 and 775. While their findings were quickly confirmed by a German oak chronology for the Northern Hemisphere (NH), the question remained if the effect was seen in both hemispheres. Here we present the first annually resolved Southern Hemisphere (SH) C-14 record spanning the interval AD 760-787, using New Zealand kauri (Agathis australis) chronology wood. An almost identical distinct increase compared to Northern Hemisphere data was observed, suggesting a cosmic event with globally uniform impact as a potential cause for the increase. Deploying a carbon cycle box model a worldwide averaged net C-14 production of 2.2 x 10(8) C-14 atoms cm(-2) was estimated, which is 3.7 times higher than the average annual C-14 production. The immediate appearance of the event in tree rings on both hemispheres suggests a short duration event of significantly less than 1 yr.


  • Geology
  • AD 775
  • modeling
  • carbon cycle
  • C-14
  • AMS


  • ISSN: 1385-013X
Florian Adolphi
E-mail: florian [dot] adolphi [at] geol [dot] lu [dot] se

Postdoctoral fellow

Quaternary Sciences

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