Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
Clim. Past, 12, 769-786, 2016
http://www.clim-past.net/12/769/2016/
doi:10.5194/cp-12-769-2016
© Author(s) 2016. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
30 Mar 2016
The WAIS Divide deep ice core WD2014 chronology – Part 2: Annual-layer counting (0–31 ka BP)
Michael Sigl1,2, Tyler J. Fudge3, Mai Winstrup3,a, Jihong Cole-Dai4, David Ferris5, Joseph R. McConnell1, Ken C. Taylor1, Kees C. Welten6, Thomas E. Woodruff7, Florian Adolphi8, Marion Bisiaux1, Edward J. Brook9, Christo Buizert9, Marc W. Caffee7,10, Nelia W. Dunbar11, Ross Edwards1,b, Lei Geng4,5,12,d, Nels Iverson11, Bess Koffman13, Lawrence Layman1, Olivia J. Maselli1, Kenneth McGwire1, Raimund Muscheler8, Kunihiko Nishiizumi6, Daniel R. Pasteris1, Rachael H. Rhodes9,c, and Todd A. Sowers14 1Desert Research Institute, Nevada System of Higher Education, Reno, NV 89512, USA
2Laboratory for Radiochemistry and Environmental Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
3Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195, USA
4Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007, USA
5Dartmouth College Department of Earth Sciences, Hanover, NH 03755, USA
6Space Science Laboratory, University of California, Berkeley, Berkeley, CA 94720, USA
7Department of Physics and Astronomy, PRIME Laboratory, Purdue University, West Lafayette, IN 47907, USA
8Department of Geology, Lund University, 223 62 Lund, Sweden
9College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
10Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN 47907, USA
11New Mexico Bureau of Geology & Mineral Resources Earth and Environmental Science Department, New Mexico Tech, Socorro, NM 87801, USA
12Department of Atmospheric Sciences, University of Washington, Seattle, WA 98195, USA
13Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA
14Department of Geosciences and Earth and Environmental Systems Institute, Pennsylvania State University, University Park, PA 16802, USA
anow at: Centre for Ice and Climate, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen, Denmark
bnow at: Department of Physics, Curtin University, Perth, Western Australia 6845, Australia
cnow at: Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ, UK
dnow at: Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE), Université Grenoble Alpes, 3800 Grenoble, France
Abstract. We present the WD2014 chronology for the upper part (0–2850 m; 31.2 ka BP) of the West Antarctic Ice Sheet (WAIS) Divide (WD) ice core. The chronology is based on counting of annual layers observed in the chemical, dust and electrical conductivity records. These layers are caused by seasonal changes in the source, transport, and deposition of aerosols. The measurements were interpreted manually and with the aid of two automated methods. We validated the chronology by comparing to two high-accuracy, absolutely dated chronologies. For the Holocene, the cosmogenic isotope records of 10Be from WAIS Divide and 14C for IntCal13 demonstrated that WD2014 was consistently accurate to better than 0.5 % of the age. For the glacial period, comparisons to the Hulu Cave chronology demonstrated that WD2014 had an accuracy of better than 1 % of the age at three abrupt climate change events between 27 and 31 ka. WD2014 has consistently younger ages than Greenland ice core chronologies during most of the Holocene. For the Younger Dryas–Preboreal transition (11.595 ka; 24 years younger) and the Bølling–Allerød Warming (14.621 ka; 7 years younger), WD2014 ages are within the combined uncertainties of the timescales. Given its high accuracy, WD2014 can become a reference chronology for the Southern Hemisphere, with synchronization to other chronologies feasible using high-quality proxies of volcanism, solar activity, atmospheric mineral dust, and atmospheric methane concentrations.

Citation: Sigl, M., Fudge, T. J., Winstrup, M., Cole-Dai, J., Ferris, D., McConnell, J. R., Taylor, K. C., Welten, K. C., Woodruff, T. E., Adolphi, F., Bisiaux, M., Brook, E. J., Buizert, C., Caffee, M. W., Dunbar, N. W., Edwards, R., Geng, L., Iverson, N., Koffman, B., Layman, L., Maselli, O. J., McGwire, K., Muscheler, R., Nishiizumi, K., Pasteris, D. R., Rhodes, R. H., and Sowers, T. A.: The WAIS Divide deep ice core WD2014 chronology – Part 2: Annual-layer counting (0–31 ka BP), Clim. Past, 12, 769-786, doi:10.5194/cp-12-769-2016, 2016.
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Short summary
Here we present a chronology (WD2014) for the upper part (0–2850 m; 31.2 ka BP) of the West Antarctic Ice Sheet (WAIS) Divide ice core, which is based on layer counting of distinctive annual cycles preserved in the elemental, chemical and electrical conductivity records. We validated the chronology by comparing it to independent high-accuracy, absolutely dated chronologies. Given its demonstrated high accuracy, WD2014 can become a reference chronology for the Southern Hemisphere.
Here we present a chronology (WD2014) for the upper part (0–2850 m; 31.2 ka BP) of the West...
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