Ground ice types and amounts in permafrost on Svalbard: Overcoming the challenge of coarse-grained sediment
Abstract
Knowledge of ground ice in permafrost are important to assess the potential geomorphic response of different periglacial landform to climate change. To measure ground-ice content typically core drilling is used to retrieve frozen core samples. Quantifications of ground ice have so far focused on fine-grained sediments, with only few results from coarse-grained sediments. This is because a large proportion of the circum-Arctic permafrost area is in low-relief landscapes dominated by fine-grained sediments, and retrieval of undisturbed core samples from coarse-grained sediments is difficult due to thaw during drilling. Since 2012, field campaigns in the high-relief landscape of the Svalbard archipelago have provided ca. 25 drill cores between 3 m and 25 m in length, using a medium sized drill rig and hand drilling, mainly from silty and sandy sediments in the large fjord-valleys, but also from different lower slope landforms. Cryostratigraphical and sedimentological analyses on these cores show that ground ice type and amount are linked to the landform and sediment type, but also that there can be locally large scale variability in the ground ice amount. However, the ground-ice content particularly in hillslope colluvium remains largely unknown due to inadequate drilling techniques and equipment. Recent observations from Svalbard indicate that landslides, increase in frequency and magnitude during prolonged thawing seasons, which might be due to degradation of ground ice. It is impossible to predict the response of these sensitive portions of the landscape without knowledge of the ground-ice conditions. This presentation will summarize recent quantifications of the ground-ice content in different landform on Svalbard and present future steps to improve frozen sample retrieval from coarse-grained sediments. These results will be applicable to mountainous permafrost environments including the widespread coarse-grained periglacial landforms with permafrost such as rock glaciers, talus, blockfields and weathered bedrock. This is necessary to be able to better understand how entire periglacial landscapes will react to changing climates.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.C54A..01C
- Keywords:
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- 0702 Permafrost;
- CRYOSPHEREDE: 1621 Cryospheric change;
- GLOBAL CHANGEDE: 1625 Geomorphology and weathering;
- GLOBAL CHANGEDE: 1807 Climate impacts;
- HYDROLOGY