WAIS Divide Deep Ice Core 0-68ka WD2014 Chronology Buizert, C.; Sigl, M.; Adolphi, F.; Baggenstos, D.; Bisiaux, M.; Brook, E.J.; Caffee, M.W.; Cheng, H.; Clow, G.D.; Cole-Dai, J.; Cuffey, K.M.; Dunbar, N.W.; Edwards, R.L.; Edwards, R.; Ferris, D.; Fudge, T.J.; Geng, L.; Iverson, N.; Koffman, B.; Layman, L.; Markle, B.R.; Maselli, O.J.; McConnell, J.R.; McGwire, K.; Muscheler, R.; Nishiizumi, K.; Pasteris, D.R.; Rhodes, R.H.; Severinghaus, J.; Sowers, T.; Steig, E.J.; Taylor, K.C.; Welten, K.C.; Winstrup, M.; Woodruff, T.E. Buizert, C. Sigl, M. Adolphi, F. Baggenstos, D. Bisiaux, M. Brook, E.J. Caffee, M.W. Cheng, H. Clow, G.D. Cole-Dai, J. Cuffey, K.M. Dunbar, N.W. Edwards, R.L. Edwards, R. Ferris, D. Fudge, T.J. Geng, L. Iverson, N. Koffman, B. Layman, L. Markle, B.R. Maselli, O.J. McConnell, J.R. McGwire, K. Muscheler, R. Nishiizumi, K. Pasteris, D.R. Rhodes, R.H. Severinghaus, J. Sowers, T. Steig, E.J. Taylor, K.C. Welten, K.C. Winstrup, M. Woodruff, T.E. earth science/paleoclimate/ice cores (age,null,two standard deviations,year,null,ice cores,null,null,N,gas age-ice age difference (delta age)) earth science/paleoclimate/ice cores (ice age,null,null,calendar year before present,null,ice cores,null,null,N,null) earth science/paleoclimate/ice cores (ice age,null,two standard deviations,year,null,ice cores,null,null,N,ice age uncertainty due to CH4 synchronization) earth science/paleoclimate/ice cores (age,null,null,year,null,ice cores,null,null,N,gas age-ice age difference (delta age)) earth science/paleoclimate/ice cores (depth,null,null,meter,null,ice cores,null,null,N,null) earth science/paleoclimate/ice cores (ice age,null,two standard deviations,year,null,ice cores,null,null,N,ice age uncertainty due to annual layer count) earth science/paleoclimate/ice cores (gas age,null,null,calendar year before present,null,ice cores,null,null,N,null) earth science/paleoclimate/ice cores (gas age,null,two standard deviations,year,null,ice cores,null,null,N,null) earth science/paleoclimate/ice core (WAIS Divide WDC06A>LATITUDE -79.4676>LONGITUDE -112.0865) The West Antarctic Ice Sheet Divide (WAIS Divide, WD) ice core is a newly drilled, high-accumulation deep ice core that provides Antarctic climate records of the past ~68 ka at unprecedented temporal resolution. The upper 2850 m (back to 31.2 ka BP) have been dated using annual-layer counting. Here we present a chronology for the deep part of the core (67.8-31.2 ka BP), which is based on stratigraphic matching to annual-layer-counted Greenland ice cores using globally well-mixed atmospheric methane. We calculate the WD gas age-ice age difference (Delta age) using a combination of firn densification modeling, ice-flow modeling, and a data set of d15N-N2, a proxy for past firn column thickness. The largest Delta age at WD occurs during the Last Glacial Maximum, and is 525 +/- 120 years. Internally consistent solutions can be found only when assuming little to no influence of impurity content on densification rates, contrary to a recently proposed hypothesis. We synchronize the WD chronology to a linearly scaled version of the layer-counted Greenland Ice Core Chronology (GICC05), which brings the age of Dansgaard-Oeschger (DO) events into agreement with the U/Th absolutely dated Hulu Cave speleothem record. The small Delta age at WD provides valuable opportunities to investigate the timing of atmospheric greenhouse gas variations relative to Antarctic climate, as well as the interhemispheric phasing of the "bipolar seesaw". STUDY NOTES: The West Antarctic Ice Sheet (WAIS) Divide deep ice core WD2014 chronology, consisting of ice age, gas age, delta-age and uncertainties therein. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Buizert, C. Investigator : Sigl, M. Investigator : Adolphi, F. Investigator : Baggenstos, D. Investigator : Bisiaux, M. Investigator : Brook, E.J. Investigator : Caffee, M.W. Investigator : Cheng, H. Investigator : Clow, G.D. Investigator : Cole-Dai, J. Investigator : Cuffey, K.M. Investigator : Dunbar, N.W. Investigator : Edwards, R.L. Investigator : Edwards, R. Investigator : Ferris, D. Investigator : Fudge, T.J. Investigator : Geng, L. Investigator : Iverson, N. Investigator : Koffman, B. Investigator : Layman, L. Investigator : Markle, B.R. Investigator : Maselli, O.J. Investigator : McConnell, J.R. Investigator : McGwire, K. Investigator : Muscheler, R. Investigator : Nishiizumi, K. Investigator : Pasteris, D.R. Investigator : Rhodes, R.H. Investigator : Severinghaus, J. Investigator : Sowers, T. Investigator : Steig, E.J. Investigator : Taylor, K.C. Investigator : Welten, K.C. Investigator : Winstrup, M. Investigator : Woodruff, T.E. 2016-06-06 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/20246 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais-wd2014agemodel.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais-wd2014agemodel.txt English https://www.ncdc.noaa.gov/paleo/study/20246 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais-wd2014agemodel.txt 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.2016The WAIS Divide deep ice core WD2014 chronology - Part 2: Annual-layer counting (0-31 ka BP)Climate of the Past123769-78610.5194/cp-12-769-2016http://www.clim-past.net/12/769/2016/ C. Buizert, K. M. Cuffey, J. P. Severinghaus, D. Baggenstos, T. J. Fudge, E. J. Steig, B. R. Markle, M. Winstrup, R. H. Rhodes, E. J. Brook, T. A. Sowers, G. D. Clow, H. Cheng, R. L. Edwards, M. Sigl, J. R. McConnell, and K. C. Taylor2015The WAIS Divide deep ice core WD2014 chronology - Part 1: Methane synchronization (68-31 ka BP) and the gas age-ice age differenceClimate of the Past112153-17310.5194/cp-11-153-2015http://www.clim-past.net/11/153/2015/cp-11-153-2015.html START YEAR: 67748 cal yr BP * END YEAR: -56 cal yr BP -112.0865 -79.4676 -112.0865 -79.4676