Deglaciation history and age estimate of the Younger Dryas end moraines in the Kalevala region, NW Russia Niko Putkinen a, * , J.P. Lunkka b , A.E.K. Ojala c , E. Kosonen c a Geological Survey of Finland, Western Finland Office, P.O. Box 97, FIN-67101 Kokkola, Finland b Institute of Geosciences, The University of Oulu, P.O. Box 3000, FIN-90014 University of Oulu, Finland c Geological Survey of Finland, Southern Finland Office, P.O. Box 96, FIN-02151 Espoo, Finland article info Article history: Received 28 January 2011 Received in revised form 23 September 2011 Accepted 26 September 2011 Available online 27 October 2011 Keywords: Glacial geology Younger Dryas end moraines Scandinavian Ice Sheet Chronology Paleomagnetic dating abstract Three lake basins were cored in the Kalevala area, northwestern Russia in order to determine the Weichselian deglaciation history of the eastern flank of the Scandinavian Ice Sheet and to date the Kalevala and Pääjärvi end moraines adjacent to these basins. Two of the lake basins, Ala-Kuittijärvi and Keski-Kuittijärvi, are situated on the proximal side of the Kalevala end moraine while the third lake basin, Tuoppajärvi, is located on the distal side of the Pääjärvi end moraine. One site from each lake basin was chosen for sedimentological and chronological study. The chronology presented in this paper is based on palaeomagnetic measurements and counting of varved clays and the results are compared to the Finnish palaeomagnetic master curve. The results indicate that the deglaciation sediments in the Ala-Kuittijärvi and Keski-Kuittijärvi lakes were deposited mainly by extra-marginal rivers, while those in Tuoppajärvi were deposited in an ice- contact setting. After the glacial meltwater input ceased, typical large lake gyttja clay/clay gyttja sedi- ment accumulated in all three basins. The palaeomagnetic record obtained from the Ala-Kuittijärvi sediment sequence extends back to 10,900 cal. BP, while that of Keski-Kuittijärvi and Tuoppajärvi dates back to 9800 cal. BP. The palaeomagnetic record, together with 450 counted varves in Ala-Kuittijärvi, indicates that the basin was deglaciated at around 11,350  300 cal. BP. Based on palaeomagnetic results, geomorphological considerations and ice retreat rates, it is estimated that the Kalevala end moraine was formed prior to 11,450  350 cal. BP, while the Pääjärvi end moraine, west of Tuoppajärvi, was formed at prior to 11,000  250 cal. BP. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction During the local last glacial maximum (LGM: ca. 20e17 ka) northwestern Russia was covered by the Scandinavian Ice Sheet (SIS) (cf. Demidov et al., 2004; Svendsen et al., 2004; Larsen et al., 2006)(Fig. 1). The SIS retreated from its maximum extent in northwestern Russia to the Scandinavian mountains between 17 and 10 ka (cf. Lunkka et al., 2001; Svendsen et al., 2004; Larsen et al., 2006). During the course of the deglaciation prominent end moraine chains were deposited in front of the ice margin all around the SIS. These end moraines were formed during minor standstills and advances of the SIS. The formation of the end moraines was ultimately related to climate changes and their effect on the behaviour of the SIS dynamics. One of the most continuous end moraine belts in the world, which can be traced over a distance of more than 2500 km, around Fennoscandia, Russian Karelia and the Kola Peninsula, was depos- ited at the margin of the SIS (cf. Andersen et al., 1995). On the eastern flank of the SIS, end moraines that belong to this contin- uous end moraine belt are the Salpausselkä I, II and III, together with the Pielisjärvi end moraines in Finland, and the Rukajärvi, Kalevala and Pääjärvi end moraines in Russian Karelia. It is gener- ally accepted that these end moraines were deposited during the Younger Dryas Stadial (YD) (12.8e11.5 ka) (Muscheler et al., 2008). The existing chronology of the Salpausselkä and Pielinen end moraines is based on varved clay chronology and biostratigraphical evidence supported by radiocarbon age determination. It is only recently that the surface exposure dating (SED) method and the palaeomagnetic method, combined with radiocarbon dating on lake sediments, have been applied to date the Salpausselkä I and II * Corresponding author. E-mail addresses: niko.putkinen@gtk.fi (N. Putkinen), juha.pekka.lunkka@oulu.fi (J.P. Lunkka), antti.ojala@gtk.fi (A.E.K. Ojala), emilia.kosonen@gtk.fi (E. Kosonen). Contents lists available at SciVerse ScienceDirect Quaternary Science Reviews journal homepage: www.elsevier.com/locate/quascirev 0277-3791/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.quascirev.2011.09.023 Quaternary Science Reviews 30 (2011) 3812e3822