The Terminations 1 and 2 as Revealed by the Record of Stable Isotopes from the EDML Ice Core

• Main Authors: Oerter, Hans, Meyer, Hanno, Miller, Heinrich, Johnsen, S., Jouzel, J., Masson-Delmotte, V., Stenni, B.
• Format: Conference Object
• Language: unknown
• Published: 2009
• Subjects: Antarc*; Antarctic; Antarctica; DML; Dronning Maud Land; EPICA; ice core
• Online Access: https://epic.awi.de/id/eprint/20102/; https://epic.awi.de/id/eprint/20102/1/Oer2009d.pdf; https://hdl.handle.net/10013/epic.32070; https://hdl.handle.net/10013/epic.32070.d001

Within the European Project for Ice Coring in Antarctica (EPICA) two deep ice cores were recovered. The second one (labelled EDML, total depth 2774m) was drilled in Dronning Maud Land (DML) in the Atlantic sector of Antarctica [1]. It is well dated down to the depth of 2416m with an age of 150 kyrs BP [2]. Stable isotopes (18O, D) have been measured with depth resolutions of 0.5m and 0.05m, and the deuterium excess values were calculated [3]. The stable isotope records for terminations 1 and 2 (T1, T2) were resampled on common time steps of 50 years. Corrections to the 18O and D values had to be added to account for surface elevation changes and changing 18O content of the sea water in the past.The most prominent difference between T1 and T2 is that the Antarctic Cold Reversal (ACR) of T1 has no analogue in T2. With the elevation corrections used in [1| T2 shows a steady increase from -51.5 to -40 over a time span of 9 kyrs, whereas T1 displays an increase from -52.5 to -44 over 8 kyrs. The influence of the elevation corrections will be discussed, which increase δ18O during MIS5.5 and lower it during the glacials. The deuterium excess shows differences towards the end of the terminations, with lower values in and after the ACR during T1. The main driver of these differences lie in the conditions prevailing in the evaporative source areas and of the subsequent transport of the moisture providing snow at the site. We infer that the atmospheric transport and the source area of precipitation or the source temperature were different for T1 and T2.[1] EPICA community members (2006) Nature 444, 195-198. [2] Ruth et al. (2007) Clim. Past 3, 475-484. [3] Stenni et al. Quatern. Sci. Rev., subm.