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Raimund Muscheler

Raimund Muscheler

Professor

Raimund Muscheler

Ice core dating with the 36Cl/10Be ratio

Author

  • Niklas Kappelt
  • Raimund Muscheler
  • Mélanie Baroni
  • Juerg Beer
  • Marcus Christl
  • Christof Vockenhuber
  • Edouard Bard
  • Eric Wolff

Summary, in English

Extremely thinned layers and possible folding make the dating of the deepest sections of ice cores especially challenging. Cosmogenic radionuclides have the potential to provide independent age estimates. The 36Cl/10Be ratio is largely independent of production rate changes that affect individual radionuclides and has an effective half-life of 384 kyr, making it an ideal tool for dating the new 1.5 Myr old ice core that the Beyond EPICA Oldest Ice Core project aims to retrieve at Little Dome C in East Antarctica. However, the loss of 36Cl through hydrogen chloride outgassing at low accumulation sites complicates its application and the long-term decay of the 36Cl/10Be ratio in ice has not been studied. Here, we show that 36Cl is preserved in glacial periods and that the 36Cl/10Be ratio decreases more slowly than expected from physical decay over the last 900 kyr. While the glacial 36Cl flux decreases at the expected rate of physical decay within the uncertainty, the 10Be flux decreases faster, which may be linked to a post-depositional mobility of 10Be in deep ice and leads to the slower decrease of the 36Cl/10Be ratio. In addition to this long-term trend, the 36Cl/10Be ratio fluctuates around a fitted decay curve, which is likely caused by different climate sensitivities of the transport and deposition pathways of the individual radionuclides. Both effects need to be better understood and quantified to improve age estimates based on the 36Cl/10Be ratio.

Department/s

  • Quaternary Sciences
  • MERGE: ModElling the Regional and Global Earth system
  • BECC: Biodiversity and Ecosystem services in a Changing Climate
  • Department of Geology

Publishing year

2025-05

Language

English

Publication/Series

Quaternary Science Reviews

Volume

355

Document type

Journal article

Publisher

Elsevier

Topic

  • Geology

Keywords

  • Be
  • Cl
  • Ice core
  • Radionuclide dating

Status

Published

Project

  • Dating Ice Cores with the 36Cl/10Be Ratio

ISBN/ISSN/Other

  • ISSN: 0277-3791