Polish Polar Research

Attempt of correlation of raised marine beaches and glacial episodes in West Spitsbergen is presented for the Middle and the Late Quaternary. A model of predominating Barents Sea shelf ice sheet during the Saalian and of co-existing distinct local ice domes during the Vistulian is postulated on the basis of varying land uplift. Glacial episodes in Spitsbergen are referred to the ones in continental Europe and North America. Rough prognosis of climatic trends is introduced.

Geological and geomorphological studies in Kaffiöyra and Hermansenöya (Oscar II Land, northwestern Spitsbergen), completed with radiocarbon datings, indicated that the Early Vistulian (Weichselian) Glaciation of presumable regional significance, occupied the whole area. Marine transgression during and after deglaciation reached at least to 65 m a.s.l. Glacioisostatic uplift and marine regression in Kaffiöyra resulted in development of older raised beaches at 52-65 m a.s.l. During the Late Vistulian, Kaffiöyra was occupied partly by outlet glaciers (Aavatsmark, Elise and Andreas), while the Dahl Glacier covered Hermansenöya. Extents of these glaciers were much greater than during the Little Ice Age. Marine transgression during deglaciation reached to 46-48 m a.s.l. at about 12-11.5 ka B.P. During glacioisostatic emergence at 11.5-9 ka B.P., ten younger raised marine beaches were formed in Kaffiöyra. Traces of a probable glacial episode at 3-2.5 ka B.P. were noted in forefields of the Aavatsmark and the Elise glaciers only. In forefields of all glaciers in Kaffiöyra there are deposits and landforms formed during glacial advances of the Little Ice Age and the following continuous retreat. The Aavatsmark Glacier was the only one to indicate surge type readvances at that time.

Relief of Svalbard is an effect of varied morphogenetic, exogenic and endogenic processes. Tectonic and glacioisostatic movements of the Earth crust have occurred many a time in this region. Glacial, marine and periglacial features are particularly common. During the Late Quaternary the western Nordenskiöld Land underwent several sea transgressions, followed by glacier advances. Basing on erratics of crystalline rocks transported by sea ice, past sea levels have been established up to 250 m a.s.l. Marine terraces above 60 m a.s.l. date back to the Late Pleistocene, the lower ones are of the Holocene age.

Studies of the Quaternary evolution of the Hornsund Region in Spitsbergen focused in nine key areas, in which detailed fieldworks with mapping and sampling to radiocarbon and thermoluminescence analyses have been done. Glacial history of the Hornsund Region is known from the Torellkjegla (Holsteinian) Interglacial up to the recent times. The Wedel Jarlsberg Land (Saalian) Glaciation was the most widespread in this part of Spitsbergen and consisted of two stades(?). It was followed by considerable glacier retreat during the Bogstranda (Eemian) Interglacial, the latter being represented by development of soils. Four glacier advances (the two younger ones are the Lisbetdalen and the Slaklidalen stages) occurred during the Sörkapp Land (Vistulian) Glaciation. Three glacier advances (Gronfjorden and Revdalen stages, followed by the Little Ice Age) were recognized for the Holocene. The oldest and highest (although somewhat questionable) raised marine beaches come presumably from the Wedel Jarlsberg Land Glaciation. The beaches 80-100 m a.s.l. were formed during the Bogstranda (Eemian) Interglacial. The beaches 20-60 m a.s.l. are correlated with the Sórkapp Land Glaciation. All the lower marine beaches were formed during the Holocene.

Marine rock-accumulative terraces at 2-230 m a.s.l. in the southern Sörkapp Land are typical for glacioisostaticly uplifted areas. The Holocene terraces reach up to 19 m a.s.l. An outstanding coastal ridge at 9-10 m a.s.l. was radiocarbon-dated at 6580±160 years B.P. No marine transgression during the Holocene on higher and older terraces was noted, what is also confirmed by well preserved raised storm ridges. Any of glacial advances during the Holocene were more extensive than the one of the Little Ice Age. However the Pleistocene glaciations were more extensive. Among glacial landforms in the area there are: ice-cored frontal and lateral moraines up to 70 m high, plains of ground, ablation and fluted moraines, complexes of glaciofluvial fans. The glaciers retreated 0.3-2 km since 1936 i.e. ca 10 m a year on the average. There are large consequent structural landslides on eastern slopes of Keilhaufjellet.

Reduced ice thickness made the glaciers of the northeastern Sörkapp Land occupy considerably smaller area in 1971 than in 1961. Glacial retreat was however more limited in this area than in a remaining part of the Sörkapp Land. Melting of firn intensified processes on mountain slopes.