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Author Bazin, L., Landais, A., Lemieux-Dudon, B., Toyé Mahamadou Kele, H., Veres, D., Parrenin, F., Martinerie, P., Ritz, C., Capron, E., Lipenkov, V., Loutre, M.-F., Raynaud, D., Vinther, B., Svensson, A., Rasmussen, S. O., Severi, M., Blunier, T., Leuenberger, M., Fischer, H., Masson-Delmotte, V., Chappellaz, J., and Wolff, E.
Title An optimized multi-proxy, multi-site Antarctic ice and gas orbital chronology (AICC2012): 120–800 ka Type Journal Article
Year 2013 Publication Clim. Past Abbreviated Journal Clim. Past
Volume 9 Issue Pages 1715-1731
Keywords
Abstract An accurate and coherent chronological framework is essential for the interpretation of climatic and environmental records obtained from deep polar ice cores. Until now, one common ice core age scale had been developed based on an inverse dating method (Datice), combining glaciological modelling with absolute and stratigraphic markers between 4 ice cores covering the last 50 ka (thousands of years before present) (Lemieux-Dudon et al., 2010).
In this paper, together with the companion paper of Veres et al. (2013), we present an extension of this work back to 800 ka for the NGRIP, TALDICE, EDML, Vostok and EDC ice cores using an improved version of the Datice tool. The AICC2012 (Antarctic Ice Core Chronology 2012) chronology includes numerous new gas and ice stratigraphiclinks as well as improved evaluation of background and associated variance scenarios. This paper concentrates on the long timescales between 120–800 ka.In this framework,new measurements ofδ18O atm over Marine Isotope Stage (MIS) 11–12 on EDC and a complete δ18O atm record of the TALDICE ice cores permit us to derive additional orbital gas age constraints. The coherency of the different orbitally deduced ages (from δ18O atm,δO2/N2 and air content has been verified before implementation in AICC2012.
The new chronology is now independent of other archives and shows only small differences, most of the time within the original uncertainty range calculated by Datice, when compared with the previous ice core reference age scale EDC3, the Dome F chronology, or using a comparison between speleothems and methane. For instance, the largest deviation between AICC2012 and EDC3 (5.4 ka) is obtained around MIS 12. Despite significant modifications of the chronological constraints around MIS 5, now independent of speleothem records in AICC2012, the date of Termination II is very close to the EDC3 one
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1814-9324 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 4534
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Author Luca Vittuari, Catherine Ritz and Hugh Corr
Title Studying ice-flows around Dome C (Antarctica): an old history of global climate Type Conference - National - Communication
Year 2014 Publication Abbreviated Journal
Volume Issue Pages
Keywords
Abstract 59° CONVEGNO NAZIONALE SIFET Tecniche Geomatiche per il Monitoraggio
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Call Number Serial 5221
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Author Fischer H, Severinghaus J, Brook E, Wolff E, Albert M, Alemany O, Arthern R, Bentley C, Blankenship D, Chappellaz J, Creyts T, Dahl-Jensen D, Dinn M, Frezzotti M, Fujita S, Gallee H, Hindmarsh R, Hudspeth D, Jugie G, Kawamura K, Lipenkov V, Miller H, Mulvaney R, Parrenin F, Pattyn F, Ritz C, Schwander J, Steinhage D, van Ommen T, Wilhelms F,
Title Where to find 1.5 million yr old ice for the IPICS “Oldest-Ice” ice core Type Journal Article
Year 2013 Publication Climate of the Past Abbreviated Journal 1814-9324
Volume 9 Issue 6 Pages 2489-2505
Keywords
Abstract The recovery of a 1.5 million yr long ice core from Antarctica represents a keystone of our understanding of Quaternary climate, the progression of glaciation over this time period and the role of greenhouse gas cycles in this progression. Here we tackle the question of where such ice may still be found in the Antarctic ice sheet. We can show that such old ice is most likely to exist in the plateau area of the East Antarctic ice sheet (EAIS) without stratigraphic disturbance and should be able to be recovered after careful pre-site selection studies. Based on a simple ice and heat flow model and glaciological observations, we conclude that positions in the vicinity of major domes and saddle position on the East Antarctic Plateau will most likely have such old ice in store and represent the best study areas for dedicated reconnaissance studies in the near future. In contrast to previous ice core drill site selections, however, we strongly suggest significantly reduced ice thickness to avoid bottom melting. For example for the geothermal heat flux and accumulation conditions at Dome C, an ice thickness lower than but close to about 2500 m would be required to find 1.5 Myr old ice (i.e., more than 700 m less than at the current EPICA Dome C drill site). Within this constraint, the resolution of an Oldest-Ice record and the distance of such old ice to the bedrock should be maximized to avoid ice flow disturbances for example, by finding locations with minimum geothermal heat flux. As the geothermal heat flux is largely unknown for the EAIS, this parameter has to be carefully determined beforehand. In addition, detailed bedrock topography and ice flow history has to be reconstructed for candidates of an Oldest-Ice ice coring site. Finally, we argue strongly for rapid access drilling before any full, deep ice coring activity commences to bring datable samples to the surface and to allow an age check of the oldest ice.
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Publisher Copernicus GmbH Place of Publication Editor
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1814-9324 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 5727
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Author Bazin L, Landais A, Masson-Delmotte V, Ritz C, Picard G, Capron E, Jouzel J, Dumont M, Leuenberger M, Prié F,
Title Phase relationships between orbital forcing and the composition of air trapped in Antarctic ice cores Type Journal Article
Year 2015 Publication Climate of the Past Discussions Abbreviated Journal
Volume 11 Issue 2 Pages 1437-1477
Keywords
Abstract Orbital tuning is central for ice core chronologies beyond annual layer counting, available back to 60 ka (i.e. thousand of years before 1950) for Greenland ice cores.
While several complementary orbital tuning tools have recently been developed using delta 18O atm,delta O2/N2, and air content with different orbital targets, quantifying their uncertainties remains a challenge. Indeed, the exact processes linking variations of these parameters, measured in the air trapped in ice, to their orbital targets are not yet fully nderstood. Here, we provide new series of delta O2/N2 and delta 18O atm data encompassing Marine Isotopic Stage (MIS) 5 (between 100–160 ka) and the oldest part(380–800 ka) of the East Antarctic EPICA Dome C (EDC) ice core. For the first time, the measurements over MIS 5 allow an inter-comparison of delta O2/N2 and delta 18O atm records from three East Antarctic ice core sites (EDC, Vostok and Dome F). This comparison highlights a site-specific relationship between delta O2/N2 and its local summer solstice insolation. Such a relationship increases the uncertainty associated with the use of delta O2/N2 as a tool for orbital tuning. Combining records of delta 18O atm and delta O2/N2 from Vostok and EDC, we evidence a loss of orbital signature for these two parameters during periods of minimum eccentricity (~400,~720–800 ka). Our dataset reveals a time-varying lag between delta O2/N2 and delta 18O atm over the last 800 ka that we interpret as variations of the lag between delta 18O atm and precession. Large lags of ~5 ka are identified during Terminations I and II, associated with strong Heinrich events. On the opposite, minimal lags (~1–2 ka) are identified during four periods characterized by high eccentricity, intermediate ice volume and no Heinrich events (MIS 6–7, the end of MIS 9, MIS 15 and MIS 17). We therefore suggest that the occurrence of Heinrich events influences the response of delta 18O atm to precession.
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Publisher Copernicus GmbH Place of Publication Editor
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1814-9359 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 6199
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Author Lucie Bazin
Title Analyse de l’air piégé dans les carottes de glace de Dôme C et Talos Dôme pour mieux contraindre le rôle du forçage orbital et des gaz à effet de serre dans les variations glaciaire-interglaciaire Type Thesis
Year 2015 Publication Abbreviated Journal
Volume Issue Pages
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Abstract Thèse soutenue le 29 janvier 2015. Université Saint Quentin.
Discipline : météorologie, océanographie physique de l'environnement
Laboratoire : LSCE
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Call Number Serial 6200
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Author Ritz Catherine, Hugh Corr, Fred Parrenin, Duncan Young, Jason Roberts, Olivier Passalacqua, Rob Mulvaney, Massimo Frezzotti, Luca Vittuari and others from the DC survey group
Title Oldest Ice reconnaissance in the vicinity of Concordia. Plans for a collaborative data-modelling approach Type Conference - International - Communication
Year 2016 Publication Abbreviated Journal
Volume Issue Pages
Keywords
Abstract Recovering a 1.5 million years record of climate and greenhouse gases from Antarctica is a major objective of the ice core community and there is an agreement that such "Oldest Ice" could be found in the plateau area of the East Antarctic Ice Sheet. The region around the permanent station of Concordia (East Antarctica) is among the few possible spots. In the framework of IPICS, it was decided to have a consortium to work on the reconnaissance for Oldest Ice in the region of Dome C. We present here the field measurements that are planned or already going on and how we plan to associate heterogenous observations and ice flow/thermal modelling to infer optimal location. The key issue for retrieving very old ice in central regions is to avoid zones with basal melting at the ice bed interface because this process removes basal layers. Modelling approach is a tool to make predictions about the thermal type of ice-bed interface as well as chronology of the deep layers, however it is limited by the badly known geothermal heat flux value and this approach has to be combined with field observations. The measurements we are considering are radar measurements (airborne, ground based, and pRES), relatively shallow drillings to measure temperature vertical profile and strain net survey.
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Call Number Serial 6503
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Author Lucie Bazin, Amaelle Landais, Emilie Capron, Valérie Masson-Delmotte, Catherine Ritz, Ghislain Picard, Jean Jouzel, Marie Dumont, Markus Leuenberger, and Frédéric Prié
Title Phase relationships between orbital forcing and the composition of air trapped in Antarctic ice cores Type Journal Article
Year 2016 Publication Climate of the past Abbreviated Journal
Volume 12 Issue 3 Pages 729-748
Keywords
Abstract Abstract. Orbital tuning is central for ice core chronologies beyond annual layer counting, available back to 60 ka (i.e. thousands of years before 1950) for Greenland ice cores. While several complementary orbital tuning tools have recently been developed using &#948;18Oatm, &#948;O2&#8260;N2 and air content with different orbital targets, quantifying their uncertainties remains a challenge. Indeed, the exact processes linking variations of these parameters, measured in the air trapped in ice, to their orbital targets are not yet fully understood. Here, we provide new series of &#948;O2&#8725;N2 and &#948;18Oatm data encompassing Marine Isotopic Stage (MIS) 5 (between 100 and 160 ka) and the oldest part (340–800 ka) of the East Antarctic EPICA Dome C (EDC) ice core. For the first time, the measurements over MIS 5 allow an inter-comparison of &#948;O2&#8725;N2 and &#948;18Oatm records from three East Antarctic ice core sites (EDC, Vostok and Dome F). This comparison highlights some site-specific &#948;O2&#8725;N2 variations. Such an observation, the evidence of a 100 ka periodicity in the &#948;O2&#8725;N2 signal and the difficulty to identify extrema and mid-slopes in &#948;O2&#8725;N2 increase the uncertainty associated with the use of &#948;O2&#8725;N2 as an orbital tuning tool, now calculated to be 3–4 ka. When combining records of &#948;18Oatm and &#948;O2&#8725;N2 from Vostok and EDC, we find a loss of orbital signature for these two parameters during periods of minimum eccentricity (&#8764; 400 ka,&#8201;&#8764; 720–800 ka). Our data set reveals a time-varying offset between &#948;O2&#8725;N2 and &#948;18Oatm records over the last 800 ka that we interpret as variations in the lagged response of &#948;18Oatm to precession. The largest offsets are identified during Terminations II, MIS 8 and MIS 16, corresponding to periods of destabilization of the Northern polar ice sheets. We therefore suggest that the occurrence of Heinrich–like events influences the response of &#948;18Oatm to precession.
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Series Volume Series Issue Edition
ISSN 1814-9324 ISBN Medium
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Notes Approved yes
Call Number Serial 6525
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Author Passalacqua, O., Gagliardini, O., Parrenin, F., Todd, J., Gillet-Chaulet, F., and Ritz, C
Title Performance and applicability of a 2.5-D ice-flow model in the vicinity of a dome Type Journal Article
Year 2016 Publication Geosci. model dev. Abbreviated Journal
Volume 9 Issue 7 Pages 2301-2313
Keywords
Abstract In ice-flow modelling, computing in 3-D requires a lot of resources, but 2-D models lack physical likelihood when the flow is diverging. That is why 2-D models accounting for the divergence, so-called 2.5-D models, are an interesting trade-off. However, the applicability of these 2.5-D models has never been systematically examined. We show that these models are ineffective in the case of highly diverging flows, but also for varying temperature, which was not suspected.
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Corporate Author Thesis Bachelor's thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1991-9603 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 6527
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Author Young, D. A., Roberts, J. L., Ritz, C., Frezzotti, M., Quartini, E., Cavitte, M. G. P., Tozer, C. R., Steinhage, D., Urbini, S., Corr, H. F. J., Van Ommen, T., and Blankenship, D. D.
Title High resolution boundary conditions of an old ice target near Dome C, Antarctica, Type Journal Article
Year 2016 Publication The cryosphere discuss. Abbreviated Journal
Volume 2016 Issue Pages 1-16
Keywords
Abstract Abstract. A high resolution (1&#8201;km line spacing) aerogeophysical survey was conducted over a region near the East Antarctic Ice Sheet's Dome C that may hold a 1.5 million year old climate record. New ice thickness data derived from an airborne coherent radar sounder was combined with unpublished data that was unavailable for earlier compilations. We find under the primary candidate region elevated rough topography, near a number of subglacial lakes, but also regions of smoother bed. The high resolution of this ice thickness dataset also allows us to explore the nature of ice thickness uncertainties in the context of radar geometry and processing.
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ISSN 1994-0440 ISBN Medium
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Notes Approved yes
Call Number Serial 6528
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Author Christo Buizert, T. J. Fudge, William H. G. Roberts, Eric J. Steig, Sam Sherriff-Tadano, Catherine Ritz, Eric Lefebvre, Jon Edwards, Kenji Kawamura, Ikumi Oyabu, Hideaki Motoyama, Emma C. Kahle, Tyler R. Jones, Ayako Abe-Ouchi, Takashi Obase, Carlos Martin, Hugh Corr, Jeffrey P. Severinghaus, Ross Beaudette, Jenna A. Epifanio, Edward J. Brook, Kaden Martin, Jérôme Chappellaz, Shuji Aoki, Takakiyo Nakazawa, Todd A. Sowers, Richard B. Alley, Jinho Ahn, Michael Sigl, Mirko Severi, Nelia W. Dunbar, Anders Svensson, John M. Fegyveresi, Chengfei He, Zhengyu Liu, Jiang Zhu, Bette L. Otto-Bliesner, Vladimir Y. Lipenkov, Masa Kageyama, Jakob Schwander
Title Antarctic surface temperature and elevation during the Last Glacial Maximum Type Journal
Year 2021 Publication Science Abbreviated Journal
Volume 372 Issue 6546 Pages 1097-1101
Keywords
Abstract Water-stable isotopes in polar ice cores are a widely used temperature proxy in paleoclimate reconstruction, yet calibration remains challenging in East Antarctica. Here, we reconstruct the magnitude and spatial pattern of Last Glacial Maximum surface cooling in Antarctica using borehole thermometry and firn properties in seven ice cores. West Antarctic sites cooled ~10°C relative to the preindustrial period. East Antarctic sites show a range from ~4° to ~7°C cooling, which is consistent with the results of global climate models when the effects of topographic changes indicated with ice core air-content data are included, but less than those indicated with the use of water-stable isotopes calibrated against modern spatial gradients. An altered Antarctic temperature inversion during the glacial reconciles our estimates with water-isotope observations.
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Notes Approved yes
Call Number Serial 8254
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