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Abstract
Stötter, J., Wastl, M. and Venzke, J.-F. (2000). The local glaciation of central Northern Iceland during the late Weichselian/early Holocene transition. In: Russell, A.J. and Marren, P.M. (eds.), Iceland 2000: Modern Processes and Past Environments, Keele University, Department of Geography Occasional Papers Series, 21, 106-108.


While the Late Weichselian/early Holocene retreat of the South Icelandic ice cap has been in the focus of many researchers (e.g. Kjartansson, 1939, 1943; Þórarinsson, 1951; Einarsson, 1960, 1961, 1963, 1968; Kaldal, 1978; Norðdahl, 1983; Ingólfsson, 1985, 1987, 1988; Pétursson, 1986; Hjartarson and Ingólfsson, 1988; Hjartarson, 1989; Geirsdóttir et al., 1997), research activities and knowledge of the extent of the local glaciation in Northern Iceland have been very limited (see Hjartarson, 1973; Müller et al., 1984, 1986; Meyer and Venzke, 1985; Venzke and Meyer, 1986; Kugelmann, 1989).
On the basis of glacial geomorphological and stratigraphical investigations a rather different pattern can be revealed for the behaviour of the outlet glacier of the South Icelandic ice cap in Eyjafjörður on the one hand and the local glaciers in the surrounding mountains of the Tröllaskagi and Flateyjarskagi peninsulas on the other hand. At a time when the outlet glacier in Eyjafjörður reached far out into the fjord, the local corrie and valley glaciers were of a very limited extent. Häberle (1991) and Stötter (1991) showed that during the Younger Dryas the glaciers in the main valleys on Tröllaskagi (e.g. Hörgárdalur, Svarfaðardalur) did not reach coastal areas, as had originally been assumed by Hjartarson (1973) or Venzke and Meyer (1986).
Based on the reconstruction of equilibrium line altitude (= ELA) depressions relative to the maximum glacier extent during the Little Ice Age (see Gross et al., 1976), present evidence allows to distinguish two stages of the local glaciation in central Northern Iceland during the Late Weichselian/early Holocene transition. The moraines left by these advances can be connected with the glacial deposits of the corresponding extents of the Eyjafjörður outlet glacier by means of marine terraces as chronoforms, tephras as chronohorizons and absolute age determinations (14C, tephrochronology).
During stage 1 the glaciers on Tröllaskagi and Flateyjarskagi showed an ELA depression of about 500 m. At the same time the outlet glacier of the South Icelandic ice cap terminated around Grenivík in the middle part of Eyjafjörður (Grenivík I and II stages corresponding to the Fornhólar and Belgsá stages of Norðdahl, 1983). Stage 1 is of Younger Dryas or later age.
During stage 2 the reconstructed ELA depressions for the local glaciers are around 200 m. The glacier in Eyjafjörður terminated near Hólar, ca. 35 km inside the present coastline. Based on tephrochronological evidence (Saksunarvatn tephra inside the moraines) stage 2 has at least Preboreal age.
Tephrochronological findings further show that since ca. 9000 BP the local glaciers in central Northern Iceland have never been much larger than during the Little Ice Age (Stötter and Wastl, 1999).
Glacier behaviour and resulting glacier extents are controlled by climate through the accumulation - ablation relation of the mass balance (see Meier, 1965). Present climate conditions in Iceland show a marked contrast between wet oceanic conditions in the south and dry more continental conditions in the north (Eyþórsson and Sigtryggsson, 1971), which are caused by different prevailing wind directions due to the position of the polar front (Glawion, 1986). This uneven distribution of preciptation is reflected in the glaciation. While Southern and Central Iceland is characterized by large ice caps the mountains of Northern Iceland carry only small corrie and valley glaciers.
Assuming that temperature variations during the Late Weichselian/early Holocene transition were more or less the same around Iceland, the different dimensions of the outlet glacier of the South Icelandic ice cap and the local glaciation in central Northern Iceland may provide an indication that the precipitation gradient between Southern and Northern Iceland was even more pronounced under colder Late Glacial conditions. This, in turn, allows conclusions about prevailing wind directions and the position of the polar front at that time.

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