Abstract
Quaternary glacial stratigraphy and relative sea-level changes reveal at least four expansions of the Kara Sea ice sheet over the Severnaya Zemlya Archipelago at 79°N in the Russian Arctic, as indicated from tills interbedded with marine sediments, exposed in stratigraphic superposition, and from raised-beach sequences that occur at altitudes up to 140 m a.s.l. Chronologic control is provided by AMS 14C, electron-spin resonance, green-stimulated luminescence, and aspartic-acid geochronology. Major glaciations followed by deglaciation and marine inundation occurred during MIS 10-9, MIS 8-7, MIS 6-5e and MIS 5d-3. The MIS 6-5e event, associated with the high marine limit, implies ice-sheet thickness of >2000 m only 200 km from the deep Arctic Ocean, consistent with published evidence of ice grounding at ∼1000 m water depth in the central Arctic Ocean. Till fabrics and glacial tectonics record repeated expansions of local ice caps exclusively, suggesting wet-based ice cap advance followed by cold-based regional ice-sheet expansion. Local ice caps over highland sites along the perimeter of the shallow Kara Sea, including the Byrranga Mountains, appear to have repeatedly fostered initiation of a large Kara Sea ice sheet, with exception of the Last Glacial Maximum (MIS 2), when Kara Sea ice did not impact Severnaya Zemlya and barely graced northernmost Taymyr Peninsula.
| Original language | English |
|---|---|
| Pages (from-to) | 2894-2936 |
| Number of pages | 43 |
| Journal | Quaternary Science Reviews |
| Volume | 25 |
| Issue number | 21-22 |
| DOIs | |
| Publication status | Published - Nov 2006 |
Bibliographical note
Funding Information:The Swedish part of this work has been financially supported by a grant from the Swedish Research Council (VR), given to Ó. Ingólfsson and P. Möller (Contract No. G-5103-20005347/2000) and is a contribution to the EU and ESF-supported project “Quaternary Environments of the Eurasian North” (QUEEN). The American contribution was supported by US National Science Foundation collaborative grants NSF OPP 0196182 and NSF OPP 0001885 to D. Lubinski and S. Forman, respectively. This project is a contribution to the NSF RAISE program sponsored by the Office of Polar Programs and ARCSS. The logistics for the 2002 and 2003 expeditions were planned and financed by the Swedish Polar Research Secretariat and the US National Science Foundation. Logistics was provided through subcontracts to INTAARI and CERPOLEX. Svend Funder, Geological Museum, Copenhagen, Denmark determined mollusc species. Anatoly Molodkov, Tallin Technical University, Estonia, performed ESR datings and provided background information on ESR dating. Darrell Kaufman, Department of Geology, Northern Arizona University provided amino acid geochronology on shell samples. Henning Lorenz, Department of Earth Sciences, Uppsala, Sweden, collaborated on satellite and aerial imagery and assisted with logistics in 2003. Svend Meldgaard Christiansen and Jette Gissel Nielsen, Department of Earth Sciences, University of Aarhus, Denmark, carried out the laboratory treatment of most samples for foraminiferal analyses. Tatiana Dmitrieva at the “All Russian oil geology Institute”, St. Petersburg, Russia, carried out foraminiferal analyses of sections Oz 1y and 1z. Skilled helicopter crews from Khatanga safely transported us sometimes in trying conditions. QSR reviewers Kurt Kjær, Copenhagen University, Denmark, and Jan Mangerud, University of Bergen, Norway, gave positive and valuable suggestion for improving this work. To all these organizations and persons we proffer our sincere gratitude.