Holocene glacier variations in central Jotunheimen, southern Norway based on distal glaciolacustrine sediment cores

Sediment cores from two glacier-fed lakes are used to reconstruct a continu ous record of glacier variations since about 10,000 cal. BP in the Smorstab btinden massif of central Jotunheinnen, southern Norway. Particular attenti on is paid to the century- to millennial-scale, pre-little Ice Age glacial signal based on an estimated temporal resolution of less than or equal to 5 5 and less than or equal to 25 yr cm(-1) for Bovertunsvatnet and Dalsvatnet , respectively. Visible lithostratigraphic variations, organic content/loss -on-ignition, calcium carbonate content, magnetic susceptibility and grain- size fractions (especially the fine silt) are used as proxy indicators of g lacier presence and extent in the lake catchments. Following deglaciation, the early Holocene was characterized by generally s mall glaciers until a major advance (the Finse Event) peaking at approximat ely 8200 cal. BP. From 7900 to at least 5300 cal. BP glaciers appear to hav e been absent from central Jotunheimen. There is evidence of glacier expans ion between about 2400 and 1600 cal. BP (the Bovertun I Event) and between about 1400 and 800 cal. BP (the Bovertun II Event) before reduced glacier e xtent during the Mediaeval Warm Period. Finally, the most extensive Neoglac ial maximum occurred during the Little Ice Age after 500 cal. BP. In additi on to providing a record of the broad pattern of climatically forced Holoce ne glacier variations, periodicities at 110-140, 200-285 and about 500 yr h ave been identified. Uncertainties remain concerning the precise timing of events, glacierization and deglacierization detection thresholds, a possibl e mid-to late-Holocene (5300-2500 cal. BP) Neoglacial build-up of small gla ciers, and shorter-term; decadal- to century-scale variations in glacier si ze, for which more proximal sites are required. (C) 2000 Elsevier Science L td. All rights reserved.