SVALBARD. Environmental changes in Svalbard since the last glacial maximum THE ROLE OF PERMAFROST

Transcription

1 SVALBARD Environmental changes in Svalbard since the last glacial maximum THE ROLE OF PERMAFROST Bernd Etzelmüller, Oslo, Norway With contribution by Hanne H. Christiansen, UNIS, Svalbard

2 Discussion points Thermal regime monitoring and modelling, and periglacial geomorphology on Svalbard Cryo-conditioning and glacier-permafrost relation Some remarks on sediment delivery to sinks under conditions of permafrost Planned activities

3 Mean annual ground temperature (MAGT) snapshot Romanovsky, Smith & Christiansen, 2010: Permafrost Thermal State in the Polar Northern Hemisphere during the International Polar Year : a Synthesis. Permafrost and Periglacial Processes, 21,

4 Permafrost Observatory Project (IPY): Kistefjellet Trolltinden Lavkavagge Abojavri Guolasjavri Iskoras A Contribution to the Thermal State of Permafrost in Norway and Svalbard (TSP NORWAY) Et prosjekt koordinert fra UNIS, Svalbard

5 50 m a.sl. Sediment (diamicton, slope) Wet (>10%) 250 m a.sl. Bedrock Dry (< 3%) 25 m a.sl. Bedrock Dry (< 3%) 465 m a.sl. Bedrock Ice-rich (> 8 %)

6 Janssonhaugen, Svalbard 15 m depth, C Isaksen et al. 2007, updated

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10 Permafrost research in Svalbard modern day processes and palaeoenvironmental reconstructions Hanne H. Christiansen The University Centre in Svalbard Arctic Geology Department & TSP team partners

11 Direct use of ice-wedge top morphology as palaeoenvironmental indicator

12 Holocene syngenetic ice-wedges during loess sedimentation OSL and/or 14 C AMS yr BP Active layer moving upwards when sedimentation is going on and stopped as the site starts being laterally eroded yr BP yr BP yr BP

13 Discussion points Thermal regime monitoring and modelling, and periglacial geomorphology on Svalbard Cryo-conditioning and glacier-permafrost relation Some remarks on sediment delivery to sinks under conditions of permafrost Planned activities

14 Permafrost and ground thermal regime are major factors in landscape development Cryo-conditioning over-arching concept for landscape evolution in cold climate Bridge between site-specific process monitoring and modelling to better understand large-scale process inter-action and landform development

15 Glacial land systems Spatial scale Process interactions in time and space Landscapes Individual processes Landscape preservation and block fields Temporal scale Paraglacial Slope channel coupling from debris flows triggered by thaw consolidation

16 CRYOSPHERIC SYSTEM Glacier realm Thermal regime Mass balance Water drainage Creep/sliding/subgl. Deformation Snow Tallik/Aggredation Pingo Icing Glacier erosion Landforms/Marginal zone Sediment budget Temperature Ice content Creep Snow Hydrology Permafrost/ periglacial realm

17 (a) (b) ELA ELA? MPA?? MPA Temperate glacier ice ELA MPA / ELA Cold glacier ice MPA (c) (e) Permafrost ELA (d) Permafrost in the glacier margins enhance MPA Basal marginal on-freezing of debris (basal MPA freezing conditions) (f) ELA Enhanced transport and accumulation of debris on the glaciers surface Development of stable ice-cored moraine land system (if debris cover is thicker than AL) No Base of permafrost/ permafrost cold ice layer Thermally unstable Etzelmüller & Hagen 2005

18 Flow till areas underlain by glacier ice Ice-cored moraines (2/3) Composite ridges Ice-cored moraines Svalbard (2) Svalbard Zone of dominating entire cold glaciers (limited glacial erosion, block-rich and stable ice-cored moraines) Zone of cold glacier margins (Ice-cored moraines, thermokarst, extensive flow till areas) 1 2 Zone of marginal onfreezing (seasonal) Small-scale ice-cores, summer melt-out Zone of marginal basal melting Continuous, stable permafrost Discontinuous and sporadic permafrost No or patchy permafrost MAAT ( C) No or only limited deformation due to high permafrost strength Zone of composite ridges (large-scale deformation and thrusting) Push moraines and melt-out of debris Zone of push moraines (small scale deformation, bulldozing) Jostedalen/Norway Finse/Norway (4) (5)

19 Discussion points Thermal regime monitoring and modelling, and periglacial geomorphology on Svalbard Cryo-conditioning and glacier-permafrost relation Some remarks on sediment delivery to sinks under conditions of permafrost Planned activities

20 Paraglacial concept Enhanced sediment yield due to availability of glacier-related deposits Church & Ryder, Slaymaker, Ballantyne (a) Temperate valley glacial system External material input (e.g. rockfall, avalanches (b) Cold or poly-thermal valley glacier system External material input (e.g. rockfall, avalanches) Subglacial material input (e.g. abrasion) Subglacial material input (e.g. abrasion) Lateral/frontal moraines Glacier bed Lateral/frontal moraines Glacier bed Faculty of mathematics Material evacuation and natural by sciences glacial melt water Material evacuation by glacial melt water

21 S(T) = e κ(t) t Stable permafrost conditions and/or permafrost aggregation bonding of sediments Temperate conditions fast removal, then surface stabilisation Degrading permafrost conditions accelerated removal

22 Sygneskardvatna, Jostedalsbreen, western Norway Nesje et al. 2000

23 Discussion points Thermal regime monitoring and modelling, and periglacial geomorphology on Svalbard Cryo-conditioning and glacier-permafrost relation Some remarks on sediment delivery to sinks under conditions of permafrost Planned activities

24 Potential high N 2 O production rate from thawing permafrost Site 1: Disko Island, West Greenland, N, W, Fen - grass dominated site. Site 2: Baffin Island, Canada, N, W, Fen - grass dominated site. Site 3: Citronen Fiord, North Greenland, N, W, Salix - grass dominated site. Site 4: Zackenberg, East Greenland, N, W Fen - grass dominated site. Site 5: Adventdalen, Svalbard, N, E, Fen - grass dominated site. Site 6: Kapp Linné, Svalbard, N, E, Fen cotton grass dominated site Elberling, B.; Christiansen, H.H. & Hansen, B.U. (2010) High nitrous oxide production from thawing permafrost.

25 Planning permafrost tunnel for improved access to ice-wedges as palaeoclimatic archieves - Perma-Lab (Infrastructure application)

26 The TTOP-model (Smith and Riseborough, 1996) Nt-factors Degree days TDD MAGST FDD Nf-factors 0 Two established models: Atmospheric lapse rate Surface offset Buffer layer: vegetation + snow Active layer Thermal offset Modified Kudryavtsev s approch (mka) (Sazonova et al., 2003) MAAT/air amplitude Vegetation model (ΔTv) Snow model (ΔTsn). MAGST Thermal conductivity ratio (Kt/Kf = rk) MAGT Kt = thawed ground thermal conductivity Kf = frozen ground thermal conductivity Depth - Height Geothermal gradient MAT Permafrost Modified from Smith & Riseborough (2002) Thermal conductivity in frozen and thawed ground (Kt and Kf) MAGT MAGT = MAAT + Surface Offset + Thermal Offset

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28 Southern Norway Northern Norway Lilleøren & Etzelmüller in review

29 BH 1 5 m BH 3 BH 4 10 m BH 5 5 m BH 6 10 m 5 m 10 m 15 m 10 m Lilleøren & Etzelmüller in prep Holocene landscape elements

30 5 m 10 m BH 1 Permafrost survived Holocene (Pleistocene/Early Holocene age) Permafrost not present during climate optimum, re-appeared after and under degradation today (Late Holocene age) Shallow permafrost probably present through LIA, disappeared early 19 th century BH 3 BH 4 5 m Permafrost patchy during climate optimum depending on site conditions, stable since (partly Pleistocene/Early Holocene age) BH 5 BH 6 Permafrost never present during Holocene 10 m 10 m 5 m 15 m 10 m

31 Lilleøren et al, in prep.

32 This we also would like to do in Svalbard (and in Iceland.. )

33 CryoMET

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