Late Glacial and Holocene Glacier Fluctuations and Climatic Variations in Southern Norway

Abstract

Deglaciation chronologies for the Trondheimsfjord region, Nordfjord area, Bergen district, Sunnhordland/Ryfylke, and the Oslofjord/Romerike area are reviewed. Holocene glacier and climate variations in southern Norway have been reconstructed by using evidence from historical data, lichenometry, rock-surface weathering from Schmidt-hammer rebound values, palaeosols, palynology, and stratigraphic evidence from distal sites characterised by glaciofluvial and glaciolacustrine sediments. Due to extensive glaciers during the “Little Ice Age”, almost all evidence from the period subsequent to the deglaciation was erased by the recent Neoglacial activity in the vicinity of the present glaciers. Records from continuous lacustrine sediment sequences downstream from glaciers are, however, considered to produce continuous, high-resolution evidence about Holocene glacier activity. The most significant climatic changes took place around the Younger Dryas/Holocene transition around 11,500 cal. yr BP (10,000 ¹⁴C yr BP), at 10,300–9900 cal. yr BP (9100 ± 200¹⁴C yr BP; the Erdalen event), around 8200 cal. yr BP (7600 ¹⁴C yr BP; the Finse event), approximately 4200 cal. yr BP (3800 ¹⁴C yr BP), and during the “Little Ice Age” (AD 1650–1930). The Holocene glacier and climate development in southern Norway is presented from sites in Sunnmøre, at Ålfotbreen, Jostedalsbreen area, Hardangerjokulen area, Jotunheimen, and Dovre. Lithostratigraphic and palaeobotanical studies suggest that most of the south Norwegian glaciers disappeared periodically during the early and mid Holocene. The glacial activity increased significantly from about 4000 cal. yr BP and the glaciers in southern Norway reached their maximum Neoglacial extent during the “Little Ice Age”, when the equilibrium-line altitude (ELA) was 100–150 m lower than at present.