Preprints
https://doi.org/10.5194/tc-2021-375
https://doi.org/10.5194/tc-2021-375
 
26 Jan 2022
26 Jan 2022
Status: this preprint is currently under review for the journal TC.

Using ice core measurements from Taylor Glacier, Antarctica to calibrate in situ cosmogenic 14C production rates by muons

Michael Dyonisius1,2, Vasilii Petrenko1, Andrew Smith3, Benjamin Hmiel1,a, Peter Neff4,1, Bin Yang3, Quan Hua3, Jochen Schmitt5, Sarah Shackleton6,b, Christo Buizert7, Philip Place1,c, James Menking7, Ross Beaudette6, Christina Harth6, Michael Kalk7, Heidi Roop4, Bernhard Bereiter6, Casey Armanetti7,d, Isaac Vimont8,e, Sylvia Englund Michel8, Edward Brook7, Jeffrey Severinghaus6, Ray Weiss6, and Joseph McConnell9 Michael Dyonisius et al.
  • 1Department of Earth and Environmental Sciences, University of Rochester, NY 14627, USA
  • 2Physics of Ice, Climate and Earth, Niels Bohr Institute, University of Copenhagen, Copenhagen 2200, Denmark
  • 3Centre for Accelerator Science (CAS), Australian Nuclear Science and Technology Organization (ANSTO), Lucas Heights, NSW 2234, Australia
  • 4Department of Soil, Water, and Climate, University of Minnesota, Saint Paul, MN 55108, USA
  • 5Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, CH-3012 Bern, Switzerland
  • 6Scripps Institution of Oceanography (SIO), University of California, San Diego, La Jolla, CA 92037, USA
  • 7College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
  • 8Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO 80303, USA
  • 9Desert Research Institute, Reno, NV 89512, USA
  • apresent address: Environmental Defense Fund, Austin, TX, USA
  • bpresent address: Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
  • cpresent address: School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, USA
  • dpresent address: Graduate School of Design, Harvard University
  • epresent address: National Oceanic and Atmospheric Administration, Global Monitoring Division, Boulder, CO, USA

Abstract. Cosmic rays entering the Earth’s atmosphere produce showers of secondary particles such as neutrons and muons. The interaction of these neutrons and muons with oxygen-16 (16O) in minerals such as ice and quartz can produce carbon-14 (14C). Analyses of in situ produced cosmogenic 14C in quartz are commonly used to investigate the Earth’s landscape evolution. In glacial ice, 14C is also incorporated through trapping of 14C-containing atmospheric gases (14CO2, 14CO, and 14CH4). Understanding the production rates of in situ cosmogenic 14C is important to deconvolve the in situ cosmogenic and atmospheric 14C signals in ice, both of which contain valuable paleoenvironmental information. Unfortunately, the in situ 14C production rates by muons (which are the dominant production mechanism at depths of > 6 m solid ice equivalent) are uncertain. In this study, we use measurements of in situ 14C in ancient ice (> 50 kilo-annum before present, ka BP) from the Taylor Glacier ablation site, Antarctica in combination with a 2D ice flow model to better constrain the rates of 14C production by muons. We find that the commonly used values for muogenic 14C production rates (Heisinger et al., 2002a, 2002b) in ice are too high by factors of 5.7 (3.6–13.9, 95 % confidence interval) and 3.7 (2.0–11.9 95 % confidence interval) for negative muon capture and fast muon interactions, respectively. Our constraints on muogenic 14C production rates in ice allow for future measurements of 14C in ice cores to be used for other applications and imply that muogenic 14C production rates in quartz are overestimated as well.

Michael Dyonisius et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on Dyonisius et al, in situ 14C', Anonymous Referee #1, 25 Feb 2022
  • RC2: 'Comment on tc-2021-375', Greg Balco, 05 Apr 2022
  • EC1: 'Comment on tc-2021-375', Benjamin Smith, 06 Apr 2022

Michael Dyonisius et al.

Michael Dyonisius et al.

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Short summary
Cosmic rays that enter the atmosphere produce secondary particles. These particles react with surface minerals to produce radioactive nuclides. Cosmogenic nuclides are often used to constrain Earth's surface processes. However, the production rates from muons are not well constrained. We measured 14C in ice with well-constrained exposure history to quantitatively constrain the production rates from muons. We find that the commonly used 14C production rates are overestimated.