Distribution of Glacial Landforms in Southern Norway in Relation to the Thermal Regime of the Last Continental Ice Sheet

Sollid, Johan Ludvig; Sørbel, Leif

doi:10.2307/521317

Cited by 60 publications

(42 citation statements)

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“…Ribbed moraines have also been postulated to form during a gradual transition from warm‐based to cold‐based conditions during a growth phase or maximum stage of glaciation in isolated patches of trapped water bodies located in an otherwise frozen bed. In this model, drumlin formation was placed prior to ribbed moraine formation and the preservation of drumlins was due to a ‘fossilization’ of the landforms by the freezing glacier (Sollid & Sørbel 1994). The subglacial meltwater flooding theory for drumlin formation was similarly applied to ribbed moraines, where they are envisaged as forming from ripple‐like cavity fills during the floods (Fisher & Shaw 1992).…”

Section: Previous Workmentioning

confidence: 99%

Seafloor evidence for palaeo‐ice streaming and calving of the grounded Irish Sea Ice Stream: Implications for the interpretation of its final deglaciation phase

Landeghem¹,

Wheeler²,

Mitchell³

2009

Boreas

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High resolution swath bathymetry data reveal a previously glaciated submarine terrain 20 km offshore Anglesey, north Wales, UK. The detailed documentation of remarkably well‐preserved subglacial and ice‐marginal bedforms provides evidence for a grounded part of the Irish Sea Ice Stream in a phase of deglaciation. The observed ribbed moraines, drumlins, flutes and eskers indicate a converging ice flow to the west, which then turns south into the deeper central Irish Sea Basin. Using the relative position of the bedforms, their spatial distribution and the morphological resemblance with bedforms described in the literature, this subglacial terrain is interpreted as representing a transition zone of frozen to thawed bed conditions during deglaciation, with an eastwards migrating thawing front that partly altered the edge of the surveyed ribbed moraine field by drumlinization. The abundant De Geer moraines and iceberg scour marks superimposed on drumlins and flutes reveal that the final retreat of the grounded ice margin in the surveyed area terminated into a water‐mass with extensive iceberg calving. As the glacial terrain is well preserved, no significant burial has taken place, either by glacially or terrestrially derived sediment. The strong tidal currents at present keep the submarine terrain swept clean of contemporary sediment cover.

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Section: Previous Workmentioning

confidence: 99%

Seafloor evidence for palaeo‐ice streaming and calving of the grounded Irish Sea Ice Stream: Implications for the interpretation of its final deglaciation phase

Landeghem¹,

Wheeler²,

Mitchell³

2009

Boreas

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“…The core area in central Fennoscandia has experienced cold-based conditions and little glacial erosion during the last glacial period (Sollid and Sørbel, 1994;Kleman et al, 1997;Kleman and Hättestrand, 1999;Stroeven et al, 2002a). Thus, we assume that the late Weichselian subglacial sediments isopached in Vestfjorden originated from erosion of the tributary fjords (including Ofoten and Tysfjorden) and the strandfl at area (Fig.…”

Section: Volume Of Late Weichselian Sediments and Average Rates Of Glmentioning

confidence: 99%

The paleo–ice stream in Vestfjorden, north Norway, over the last 35 k.y.: Glacial erosion and sediment yield

Laberg¹,

Eilertsen²,

Vorren³

2009

Geological Society of America Bulletin

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The basal erosion rate and sediment yield of the Vestfjorden paleo-ice stream, a marine-based part of the northwestern Fenno scandian Ice Sheet, were elucidated during a complete advance-retreat cycle using high-resolution seismic data and multibeam bathymetry. In most of the area, there is a semitransparent, continuous upper seismic unit showing a southwestward (downfjord) progradational pattern with megascale glacial lineations on top, interpreted to represent a subglacial deformable till. The till formed a continuous bed beneath most of the Vestfjorden paleo-ice stream, except for the upstream parts, where ice streaming is inferred to have occurred above bedrock. The till thickness is up to an order of magnitude larger than those reported from modern ice streams due to a more effi cient transfer of material from the source area to the ice streambed. The till is draped by glaciomarine and marine sediments. The average sedimentation rate in the paleo-ice stream drainage route during the period from ca. 35 to 11 ka was ~2.6 m/k.y. This equals an average sediment discharge of 35 × 10 6 t/yr and an average sediment yield of 6.4 × 10 3 t km -2 yr -1 . From this, we estimate an average erosion depth of ~40 m or rate of ~1.7 mm/yr in the sediment source area, the encircling fjord, and valley landscape. These values are in agreement with the results reported from similar settings in southern Norway, but they are nearly twice the fi gures reported for arctic ice-stream erosion. They are also signifi cantly higher than the rates estimated from the British Ice Sheet. In conclusion, glacial erosion beneath paleo-ice streams seems to have been more effi cient in subarctic regions.

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“…For example, moraine features, drumlinizations, till ridges, boulder fields and fluvial patterns of a pre-Late Weichselian age have been reported from Scandinavia (Lagerbäck, 1988;Rhode, 1988;Kleman, 1992;Sollid and Sørbel, 1994) and from North America and Canada (England, 1986;Dyke and Morris, 1988;Boulton and Clark, 1990;. Preserved deep weathering remnants have been reported from East Greenland (Funder, 1972), North America (Sugden, 1978) and Scotland (Hall and Sugden, 1987).…”

Section: Preservation In Previously Glaciated Areasmentioning

confidence: 99%

Subglacial Preservation of Valley Morphology at Amundsenisen, Western Dronning Maud Land, Antarctica

Näslund

1997

Earth Surf. Process. Landforms

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Figure 4 did not reproduce well in the final printing, for which the publishers apologise. Figure 4. The subglacial valley system at Amundsenisen which was mapped in more detail, shown with a 2× vertical exaggeration and contour interval of 25 m. The bed surface has been corrected for the ice surface topography. Data on bed and ice sheet topography were collected with a spacing of 500 m or less along the profiles, shown by the dotted lines on the upper ice surface. The general valley morphology indicates that the valley was formed by erosion by a wet-based local mountain glacier. This site is used for a comparative calculation of basal temperature for discussing where, on a local scale, preservation of landforms may occur

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Distribution of Glacial Landforms in Southern Norway in Relation to the Thermal Regime of the Last Continental Ice Sheet

Cited by 60 publications

References 0 publications

Seafloor evidence for palaeo‐ice streaming and calving of the grounded Irish Sea Ice Stream: Implications for the interpretation of its final deglaciation phase

Seafloor evidence for palaeo‐ice streaming and calving of the grounded Irish Sea Ice Stream: Implications for the interpretation of its final deglaciation phase

The paleo–ice stream in Vestfjorden, north Norway, over the last 35 k.y.: Glacial erosion and sediment yield

Subglacial Preservation of Valley Morphology at Amundsenisen, Western Dronning Maud Land, Antarctica

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