Early Pleistocene interglacial-glacial deposits in Denmark linked to the Matuyama Chron and MIS 22–21

Middle Jutland, Denmark, holds some of the oldest Pleistocene deposits in northern Europe, both interglacial and glacial deposits are present. The interglacial deposits, recognized as the Harreskovian Interglacial, have traditionally been referred to the Cromerian Complex, but the reason for this assignment is unclear. It is, however, evident that the deposits are connected to the early expansion of the Scandinavian ice sheet onto the North European lowland. The scope of this paper is to examine and hopefully clarify some of these issues. The critical geological unit in the study is the Harreskovian Interglacial gyttja. This gyttja is overlain by two interstadial units, Ølgod I and Ølgod II, and underlain by totally 54 m of glacial deposits comprising five tills alternating with beds of meltwater sand. A closely related succession appears at Starup 45 km south of Harreskov, but here the glacial deposits below the interglacial sediments consist entirely of glacial lake clay. The glacial succession rests directly on Neogene sand. We have analysed 112 samples for palaeomagnetic polarity. The samples gave all reverse polarity except for the lowermost four samples at Starup, which showed normal polarity. Correlating our results with the Global Magnetic Polarity Time Scale (GMPTS) and the benthic Marine Isotope Stages (MIS), we assign the sedimentary successions as a whole to the reverse Matuyama Chron. The Harreskovian Interglacial and the two overlying interstadials are correlated to MIS 21, whereas the tills and meltwater sand are referred to MIS 22. The normal polarity samples at the base of the lacustrine clay at Starup are referred to the Kamikatsura normal excursion. We suggest that the tills represent the first advances of the Scandinavian Ice Sheet into Denmark. The advance probably stopped in the southern part of Jutland, as indicated by the lack of evidence for ice in Schleswig-Holstein and northern Germany.