724 m deep ice core from Akademii Nauk ice cap Severnaya Zemlya (Russian Arctic) - electrical conductivity measurements and isotopic record


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Diedrich.Fritzsche [ at ] awi.de

Abstract

In the Eurasian Arctic, the archipelago of Severnaya Zemlya is the most eastern one which is covered by a considerable ice cap, giving the opportunity to study regional climate signals from the Holocene period. The Academii Nauk ice cap (Komsomolets Island) was chosen for drilling a deep ice core because it is the thickest and coldest ice cap on Severnaya Zemlya. A suitable drilling site was found at 80°31'N 94°49'E by the help of airborne radio-echo sounding data and SAR interferometry. The ice thickness was 724 m at this location. Drilling was carried out between 1999 and 2001 reaching bedrock. It was a joint project of the Alfred Wegener Institute (Germany), the Arctic and Antarctic Research Institute, and the Mining Institute (Russia, St.Petersburg both). An electromechanical ice core drill (KEMS-112M) was used, the same type as at Vostok Station, Antarctica. The paper presents the results of electrical conductivity measurements (DEP) of the whole ice core. Several zones with high conductivity were assumed to be caused by major volcanic eruptions. By help of catalogues of historical volcanic events we used these signals for core dating of the upper 245 meters. The time scale developed this way is in good agreement with horizons of enriched radioactivity caused by nuclear weapon tests in the early 1960's and by the Chernobyl accident. The d180 record fits almost perfectly to values published earlier by Klementev et al. for Akademii Nauk, however, we have no evidence for the age model used in this Russian paper. We found annual accumulation rates in the isotope record and in the electrical data indicating none-steady state conditions of this glacier in the past. Hence, the core ages are overestimated by flow models. There seems to be an age discordance in the deepest part of the core. For Akademii Nauk ice cap the isotope data indicate a climate warming since app. 1860 which is much higher than found at central Greenland (GRIP/GISP2), Devon lsland or Hans Tausen ice cap. REFERENCE Klementev, O.L.; Potapenko, V. Yu.; Savatyugin, L.M. & Nikolaev, V.l.: Studies of the intemal structure and thennal-hydrodynarnic state of Vavilov Glacier, Archipelago Sevemaya Zernlya. IAHS Publ. 208, 1991, p.49-59



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Conference (Invited talk)
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Not peer-reviewed
Publication Status
Published
Event Details
10th Seoul International Symposium on Polar Sciences, Recent Approaches in Polar Earth Sciences, 21 Oct 2003 - 23 Oct 2003, Incheon, Korea.
Eprint ID
9568
Cite as
Fritzsche, D. , Schütt, R. , Meyer, H. , Miller, H. and Wilhelms, F. (2003): 724 m deep ice core from Akademii Nauk ice cap Severnaya Zemlya (Russian Arctic) - electrical conductivity measurements and isotopic record , 10th Seoul International Symposium on Polar Sciences, Recent Approaches in Polar Earth Sciences, Incheon, Korea, 21 October 2003 - 23 October 2003 .


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