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GLACIER MAXIMA, MINIMA AND CLIMATE IN TRöLLASKAGI, NORTHERN ICELAND
CASELY, ANDREW F Institute of Geography, University of Edinburgh.
Glacier fluctuations are commonly used as a proxy for climatic changes. This is achieved primarily through the mapping and investigation of moraines as indicators of glacier highstands. Consequently, the record is frequently incomplete due to censorship of the record by subsequent advances (Kirkbride and Brazier, 1998), and there is rarely evidence of glacier retreat. In the Tröllaskagi region of northern Iceland, there are landforms linked to present activity of ice, including corrie and small valley glaciers, as well as rock glaciers. Vatnsdalur contains six small corrie glaciers of c.0.9km - 2km length, c.0.1 - 1km2 area, situated between 900m and 1200m altitude (Fig. 1). There is also considerable geomorphological evidence of past glacier highstands, including moraines dated to c.6000BP - 4700±205 14C BP and <3470±160 14C BP by Stötter (1991), as well as several Little Ice Age highstands. Advance and retreat of glaciers in this region has been linked to climatic variables by Caseldine (1987; 1991) showing sensitivity to precipitation as well as rapid response, and they are thus potentially important in understanding Late Holocene climatic change in Iceland. These glaciers have retreated up to 1.7km from their maximum Holocene extents.
A 2.5m long core, Skeiðsvatn III, was extracted from the lake Skeiðsvatn (Fig. 2) in Vatnsdalur, containing sediments dating to at least 1380±45 14C BP (between 636 and 686 cal. AD to 1σ). Results from the anaysis of sediments in this core are presented. The sediments contain evidence that the catchment may have been ice-free prior to c.650AD, or that the ice masses in the catchment were sufficiently small so as to be inactive. Using geomorphology and tephrochronology as well as the lake sediments, this paper explores the significance of glacier retreat in the catchment, as well as the influence of other geomorphic activity (including rock glaciers, landslides and periglaciation) on both the lake sediments and the geomorphic record of glacier extent.
Caseldine, C. J., 1987, Neoglacial Glacier Variations in Northern Iceland - Examples from the Eyjafjordur Area: Arctic and Alpine Research,v. 19(3), p. 296-304.
Caseldine, C. J., 1991, Lichenometric dating, lichen population studies and Holocene glacial history of the Tröllaskagi, Northern Iceland. In: Maizels, J. K. and Caseldine, C. (Eds.) Environmental Change in Iceland: Past and Present Dordrecht, Kluwer Academic Publishers. p. 219-223.
Kirkbride, M. P. and Brazier, V., 1998, A critical evaluation of the use of glacier chronologies in climatic reconstruction, with reference to New Zealand.: Quaternary Proceedings,v. 6, p. 55-64.
Stötter, J., 1991, New observations on the postglacial glacial history of Tröllaskagi, Northern Iceland. In: Maizels, J. K. and Caseldine, C. (Eds.) Environmental Change in Iceland: Past and Present Dordrecht, Kluwer Academic Publishers. p. 181-192.
Figure 1. Perspective view of Vatnsdalur, showing the context of Skeiðsvatn and the six corrie glaciers. Image created from a preliminary DEM.
Figure 2. Looking south towards Vatnsdalsjökull from Skeiðsvatn
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