Holocene development and geomorphic processes at Omnsbreen, southern Norway: Evidence for glacier-permafrost interactions

被引:7
|
作者
Lilleoren, Karianne S. [1 ]
Humlum, Ole [1 ,2 ]
Nesje, Atle [3 ,4 ]
Etzelmuller, Bernd [1 ]
机构
[1] Univ Oslo, N-0316 Oslo, Norway
[2] Univ Ctr Svalbard, Svalbard, Norway
[3] Univ Bergen, N-5020 Bergen, Norway
[4] Uni Bjerknes Ctr Climate Res, Bergen, Norway
来源
HOLOCENE | 2013年 / 23卷 / 06期
关键词
geomorphology; glacier; glacier-permafrost interactions; 'Little Ice Age'; Omnsbreen; permafrost; WINTER-PRECIPITATION; ICE-AGE; THERMAL REGIME; MASS-BALANCE; CLIMATE; MOUNTAIN; FLUCTUATIONS; FENNOSCANDIA; CIRCULATION; JOTUNHEIMEN;
D O I
10.1177/0959683612471984
中图分类号
P9 [自然地理学];
学科分类号
0705 ; 070501 ;
摘要
Omnsbreen is a small (<0.5 km(2)) and degrading glacier situated at the regional lower limit of present-day permafrost distribution and glaciation. At present, the existence of Omnsbreen is mainly dependent on wind-borne snow redistributed by the prevailing westerly winter-wind, and lies in an area of marginal permafrost occurrence. During the 'Little Ice Age' (LIA) both the glacier and the distribution of permafrost in the area reached their maximum late-Holocene areal extents. The first occurrence of Omnsbreen is recorded in sediment cores retrieved from a proglacial lake and dated at AD 1425, and marks the onset of the local LIA. Reconstruction of the maximum LIA extent by means of geomorphic indicators revealed a size of 7.1 km(2), a volume of more than 0.25 km(3) and a maximum glacier thickness of 110 m. Since the LIA Omnsbreen has been reduced by more than 90% in area. Omnsbreen retreated rapidly from its LIA maximum, which we suggest was determined by the shape of the glacier, filling up the valley, and hence being unable to accumulate wind-borne snow. Prominent glacier marginal landforms are absent along the maximum LIA extent of Omnsbreen. We propose that the lack of glacier marginal landforms in this case is indicative of a cold glacier margin, and that the landscape evolution in maritime and marginal permafrost regions is characterised as being closely connected with glacial activity.
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页码:796 / 809
页数:14
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