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Bakke, J., S. Olaf Dahl, O. Paasche, R. Lovlie, A. Nesje. 2005. Glacier fluctuations, equilibrium-line altitudes and palaeoclimate
in Lyngen, northern Norway, during the Lateglacial and Holocene. The Holocene Vol. 15, No. 4, pp. 518-540
| Data Coverage |
North: 69.73 * South: 69.73 |
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West: 19.98 * East: 19.98 |
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Altitude: 35 m |
Start Year: 20000 cal yr BP * End Year: 0 cal yr BP
Data: Please Cite Data Contributors!
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Summary: Based on lacustrine and morpho-stratigraphical evidence from Lyngen in Troms, northern Norway, 13 marginal moraines have
been mapped in front of Lenangsbreene in Strupskardet. Moraines M1-M13 are inferred to represent glacier halts or advance/readvance
taking place during the Lateglacial and Holocene. The presence of collapse depressions suggests that some of them were ice
cored (M1-M3). A chronological framework, taking into account a combination of former shorelines and related glacier-meltwater
channels, lichenometry and AMS radiocarbon-dated lacustrine sediments spanning the last 20,000 cal. yr BP, has been established.
The distal glacier-fed lake Aspvatnet was isolated from the sea c.10,300 cal. yr BP, and the lacustrine sediments have been
investigated by use of loss-on-ignition (LOI) magnetic susceptibility, water content, wet and dry bulk density (DBD), and
the magnetic parameters anhysteretic remanent magnetization (ARM) and saturation remanent magnetization (SIRM). There is,
in general, good agreement between physical sediment parameters and magnetic parameters. DBD, a combination of medium and
fine silt and the two statistical parameters 'sorting' and 'mean' have been used to construct a high-resolution glacier-fluctuation
curve for the last 3800 cal. yr BP. Based on an accumulation-area ratio (AAR) of 0.6 and an ablation-accumulation balance
ratio (ABR) approach, a continuous temperature-precipitation- wind equilibrium-line altitude (TPW-ELA) curve for the last
20,000 cal. yr BP has been constructed. Using an established exponential relationship between mean ablation-season temperature
and mean annual solid precipitation at the ELA of Norwegian glaciers, variations in mean winter precipitation (snow) are
quantified using an independent proxy for summer temperature. Mean annual winter precipitation varied from 500 to 5000 mm
water equivalent, and on average, Holocene estimates are c. 50% higher than similar figures from the Lateglacial. The two
driest periods occurred during Heinrich events 1 (H1) (17,500-16,500) and 0 (H0) (13,000-12,200), whereas freshwater pulses
to the North Atlantic had apparently no systematic impact on mean winter precipitation. Based on the winter precipitation
curve from Lyngen, the atmospheric circulation responded to the sea surface temperature (SST) lowering associated with H1
and H0. The dry and cold climate during the events led to formation of talus-derived rock glaciers at sea level.
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