Quaternary Science Reviews 21 (2002) 111–119 The extent of the Barents–Kara ice sheet during the Last Glacial Maximum Jan Mangeruda,*, Valery Astakhovb, John-Inge Svendsenc a Department of Geology, University of Bergen, Alle!gt 41, N-5007 Bergen, Norway b Geological Faculty, Petersburg University, Universitetskaya 7/9, 199034 St. Petersburg, Russian Federation c Centre for Studies of the Environment and Resources, University of Bergen, Hyteknologisenteret, N-5020 Bergen, Norway Received 30 January 2001; accepted 18 July 2001 Abstract It has been a long-standing discussion whether the Barents–Kara Ice Sheet expanded onto mainland Russia during the Last Glacial Maximum (LGM). In this paper, we describe many well-dated (by conventional and AMS 14C methods and optically stimulated luminescence) sedimentary sequences in the controversial area of Northern Russia. The sequences discussed are not covered by till, and yet all predate the LGM. The deposits consist mostly of aeolian or lacustrine, easily deformable soft silt and fine sand. Two sites feature frozen mammoth carcasses and three sites contain Palaeolithic artefacts and mammalian bones. We emphasise that these formations show no sign of having been overridden by an ice sheet. At several sites, deposition of aeolian sediments and formation of ice wedges took place during the LGM time span. These observations present unambiguous proof that the Barents–Kara Ice Sheet did not cover mainland Russia during LGM, with a possible exception for the northern tip of the Taimyr Peninsula. r 2001 Elsevier Science Ltd. All rights reserved. 1. Introduction et al., 1995). However, the dimension of the Barents– Kara Ice Sheet during the LGM has been controversial Results of different methods of estimating the total over the last decades. Ice sheets of widely different sizes volume of glacial ice on earth during the Last Glacial have been suggested (CLIMAP, 1981; Denton and Maximum (LGM) were extensively discussed during the Hughes, 1981; Grosswald, 1993, 1998; Peltier, 1994; EPILOG symposium. The principal method is to Velichko et al., 1997; Svendsen et al., 1999; Petit-Maire calculate volumes of individual ice sheets by using their et al., 2000), although in all reconstructions the LGM mapped areas and modelled ice thicknesses. Therefore, ice sheet boundary is located well inside the maximum empirical geological evidence of the extent of the ice Quaternary drift limits. sheets is needed. In the present paper, we describe and In the reconstructions of Svendsen et al. (1999, discuss data constraining the southern extent of the submitted), which we presented at the EPILOG Barents–Kara Ice Sheet during the LGM. The time of symposium (Fig. 1), the western and northern margins the LGM is used in the sense of EPILOG; i.e. as the time of the ice sheet are localised along the edge of the slice 18–21 14C kyr or about 21–24,000 cal yr BP. continental shelf (Landvik et al., 1998), which agrees An ice sheet centred over the Barents and Kara seas well with the corresponding limits in Grosswald’s (1993) (hereafter the Barents–Kara Ice Sheet) expanded onto reconstruction. This is also the maximum feasible extent the Russian mainland several times during the Quatern- for a grounded ice sheet because beyond the shelf break ary (e.g. Astakhov, 1976). At its Quaternary maximum the water depth becomes so deep that the ice front extent, this ice sheet covered vast areas of West Siberia would float. A possible expansion of this ice sheet into and European Russia (Arkhipov et al., 1986; Arkhipov the deep sea as a floating ice shelf would not contribute to a lowering of the global sea level. Therefore, if the Barents–Kara Ice Sheet was significantly larger than *Corresponding author. Tel.: +47-55-58-35-04; fax: +47-55-58-94- that shown in Fig. 1, the additional ice must have 16. resided on mainland Russia, especially in the Pechora E-mail address: [email protected] (J. Mangerud). Lowland and the West Siberian Plain (Figs. 1 and 2). 0277-3791/02/$ - see front matter r 2001 Elsevier Science Ltd. All rights reserved. PII: S 0277-3791(01)00088-9 112 J. Mangerud et al. / Quaternary Science Reviews 21 (2002) 111–119 Fig. 1. Limits of the Barents–Kara Ice Sheet during the LGM according to Svendsen et al. (submitted), which is a slightly revised version of the map in Svendsen et al. (1999). It should be noted that except for the southern part, the precise position of the ice limit in the Kara Sea is uncertain. This has indeed been suggested in many of the earlier form, that formed the basis for the LGM reconstruction published reconstructions of the LGM ice sheets by Svendsen et al. (1999), supplemented by some results (CLIMAP, 1981; Denton and Hughes, 1981; Grosswald, obtained later. 1993, 1998; Peltier, 1994; Petit-Maire et al., 2000). We emphasise that all the stratigraphic sections and During the EPILOG symposium Grosswald again geomorphological features described below are located presented an LGM reconstruction with an ice limit within the ice limits proposed by Grosswald (Fig. 2). All located far to the south on the Russian mainland sediments and landforms predate the time of LGM but (Fig. 2), arguing that glaciological modelling supports none of the sites show any sign of glacial overriding. that alternative. Russian, Western European and Some sections also show deposition of non-glacial American field geologists who presently work in the sediments at LGM time. The observations are therefore Russian Arctic, on the other hand, maintain that the incompatible with Grosswald’s and other similar recon- existing field observations and geochronometric data structions of a large LGM ice sheet in this area. Details falsify Grosswald’s hypothesis (Astakhov et al., 1999; on the sections, methods, dating results, etc, are Forman et al., 1999; Larsen et al., 1999; Mangerud et al., contained in the referred literature. 1999; Svendsen et al., 1999; Polyak et al., 2000). However, the discussion at the EPILOG symposium shows that Grosswald’s idea is still considered as a 2. Pechora Lowland and Pechora Sea viable alternative among researchers from other dis- ciplines of Quaternary science, or by those who have not The Pechora River runs from the large lowland in the studied this region themselves. Therefore, we will here NE corner of Europe into the SE part of the Barents present a few selected key observations, in a simplified Sea, sometimes named the Pechora Sea (Figs. 1 and 2). J. Mangerud et al. / Quaternary Science Reviews 21 (2002) 111–119 113 Fig. 2. Map of Northern Russia showing the proposed limits for the Barents–Kara Ice Sheet during the LGM according to Grosswald (1993, 1998) and Svendsen et al. (submitted). Sites described in the text and for which obtained dates and the stratigraphy or morphology demonstrates that they have not been overrun by a LGM glacier are marked. Grosswald (1993, 1998) placed the LGM glacial limit in moth, and a few artefacts were found in a cross-bedded the southern part of the Pechora Lowland (Fig. 2). gravel, interpreted as river-channel deposits (Mangerud et al., 1999; Pavlov et al., 2001). The 14C dates from the 2.1. Palaeolithic sites bones yielded ages of 35–37 ka (Fig. 3). The gravel is covered by alluvial sand, interpreted as a point-bar The Byzovaya Palaeolithic site (Locality no. 1, Fig. 2) sequence. A series of AMS 14C dates on terrestrial plant has been known for decades. Recently, we have made remains (leaves, mosses, etc.) from these alluvial large excavations in order to improve our knowledge sediments yielded ages in the range 31–24 ka. The about the archaeological remains and the sediments sequence is capped by undisturbed aeolian fine sand/ (Mangerud et al., 1999; Heggen, 2000). We have coarse silt OSL-dated to 20–14 ka (Fig. 3). Just like the obtained 25 radiocarbon dates on bones and mammoth Byzovaya site wind-blown sediments accumulated here tusks from the cultural layer, which all yielded ages in during the LGM. the range 25.5–30.0 ka, except for one date that yielded At the Pymva Shor site (no. 3, Fig. 2), several shallow 3372 ka. Only some of the dates are plotted in Fig. 3. pits have been excavated (Mangerud et al., 1999). Here, The layer with bones and artefacts is blanketed by a animal bones have yielded radiocarbon dates traversing 10 m thick sequence of unconsolidated aeolian sand and the LGM time slice: 26.2, 21.9, 20.0, 16.9, 16.5, 16.5 and silt, in places intercalated with beds deposited by 15.8 ka. solifluction or debris flows from the valley slopes. A series of optically stimulated luminescence (OSL) dates 2.2. Early Weichselian shorelines from the aeolian sediments have yielded ages in the range 32–18 ka, indicating that wind-blown sand, Shorelines of the large, pro-glacial, ice-dammed Lake intercalated with solifluction deposits, accumulated here Komi mapped by aerial photography are morphologi- during the LGM (Fig. 3). cally expressed as many kilometre long knicklines or At the Mamontavaya Kurya Palaeolithic site (no. 2, sand bars following the 100 m altitude contour across Fig. 2), many bones of large mammals, mostly mam- most of the Pechora Lowland (Fig. 2) (Astakhov et al., 114 J. Man g erud et al. / Quaternary Science Re v iews 21 (2002) 111–119 Fig. 3. Simplified logs from sites described in the text plotted in an N–S profile from the Pechora Sea to the southern Pechora Lowland. Locations on the map in Fig. 2 are given as site nos. (in parentheses) above each log. For Byzovaya the log gives a synthesis of the excavations and is based on Mangerud et al.