On the suitability of partially clathrated ice for analysis
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TitleOn the suitability of partially clathrated ice for analysis of concentration and δ13C of palaeo-atmospheric CO2AbstractThe stable carbon isotopic signature of carbon dioxide (Î´13CO2) measured in the air occlusions of polar ice provides important constraints on the carbon cycle in past climates. In order to exploit this information for previous glacial periods, one must use deep, clathrated ice, where the occluded air is preserved not in bubbles but in the form of air hydrates. Therefore, it must be established whether the original atmospheric Î´13CO2 signature can be reconstructed from clathrated ice. We present a comparative study using coeval bubbly ice from Berkner Island and ice from the bubble-clathrate transformation zone (BCTZ) of EPICA Dome C (EDC). In the EDC samples the gas is partitioned into clathrates and remaining bubbles as shown by erroneously low and scattered CO2 concentration values, presenting a worst-case test for Î´13CO2 reconstructions. Even so, the reconstructed atmospheric Î´13CO2 values show only slightly larger scatter. The difference to data from coeval bubbly ice is statistically significant. However, the 0.16â€ Degrees magnitude of the offset is small for practical purposes, especially in light of uncertainty from non-uniform corrections for diffusion related fractionation that could contribute to the discrepancy. Our results are promising for palaeo-atmospheric studies of Î´13CO2 using a ball mill dry extraction technique below the BCTZ of ice cores, where gas is not subject to fractionation into microfractures and between clathrate and bubble reservoirs. â"' 2011 Elsevier B.V.AcknowledgementsThis project could not have been conducted without the development work of J. Lavriv c, who set up the IRMS system at LGGE.We thank M. Le Floch for conducting the GC measurements at LGGE.We are grateful to M. Francis and G. Dreyfus for sharing nitrogen isotope information. We thank S. Mikaloff-Fletcher and J. Deslippe for their support with the statistical analysis. This work is a contribution to the European Project for Ice Coring in Antarctica (EPICA), a joint ESF (European Science Foundation)/European Comission scientific programme, funded by the European Union and by national contributions from Belgium, Denmark, France, Germany, Italy, the Netherlands, Norway, Sweden, Switzerland and the United Kingdom. The main logistic support was provided by the Institut Polaire FranÂ¸ cais - Paul Emile Victor (IPEV) and PNRA (at Dome C). This is EPICA publication no 277. The Berkner Island project was financed by the British Antarctic Survey and Natural Environment Research Council of the UK, and IPEV of France. Additional funding was provided by the QUEST-INSU project DESIRE, the European Research Training and Mobility Network GREENCYCLES (A.L.) and the French ANR Dome A (ANR-07-BLAN-0125). This work was also supported by the Past4Future project from the European CommissionÅ› 7th Framework Programme under grant agreement no 243908 (J.C.), and is Past4Future contribution number 7. Additional support comes from New Zealand Foundation for Research, Science and Technology contract C01X0703 (H.S.). Long-term support for the mass spectrometry work at LGGE was provided by the Fondation de France and the Balzan Prize.
1st AuthorSchaefer, H.AuthorSchaefer, H.Lourantou, A.Chappellaz, J.Lüthi, D.Bereiter, B.Barnola, J.-M.Year2011JournalEarth and Planetary Science LettersVolume307Number3/04/2017Pages334-340DOI10.1016/j.epsl.2011.05.007URLhttps://www.scopus.com/inward/recor.....ddd573fea486334d5cf7d8862KeywordsBerkner IslandBubble clathrate transformationEPICA Dome CIce coreStable carbon isotope ratio, Atmospheric compositionBall millsCarbon dioxideDomesIsotopes, Ice, atmospheric chemistrycarbon cyclecarbon dioxidecarbon isotope ratioice corestable isotope, rank1Author KeywordsBerkner IslandBubble clathrate transformationCarbon dioxideEPICA Dome CIce coreStable carbon isotope ratio
TypeArticleCitationSchaefer, H., Lourantou, A., Chappellaz, J., Lüthi, D., Bereiter, B. and Barnola, J.-M. (2011) On the suitability of partially clathrated ice for analysis of concentration and δ13C of palaeo-atmospheric CO2. Earth and Planetary Science Letters, 307(3-4): 334-340 doi:10.1016/j.epsl.2011.05.007
Antarctica NZ (26th Nov 2018). On the suitability of partially clathrated ice for analysis . In Website Antarctica NZ. Retrieved 21st Oct 2021 14:15, from https://adam.antarcticanz.govt.nz/nodes/view/63756