scholarly journals Distribution and glaciological implications of relict surfaces on the Ultevis plateau, northwestern Sweden

1999 ◽  
Vol 28 ◽  
pp. 202-208 ◽  
Author(s):  
Anders Clarhäll ◽  
Johan Kleman
Keyword(s):  
Transition Zone ◽  
Marginal Zone ◽  
Ice Sheet ◽  
Ice Cover ◽  
The Other ◽  
Thermal Transition ◽  
Scandinavian Ice Sheet ◽  
Base Boundary ◽  
Landscape Types ◽  
Late Weichselian

AbstractThe Ultevis plateau, northwestern Sweden, has a relief of less than 200 m, yet bears three different kinds of landscape, classified according to the degree of glacial erosion. The first type is restricted mainly to topographic highs and has almost entirely escaped erosion, despite complete and prolonged ice cover during the late Weichselian. The other two landscape types are distinguished depending on whether older land- forms have been completely erased or not. The latter two appear to have undergone erosion only briefly. The transitions between landscape zones are usually sharp, and specific boundary landforms occur. The Scandinavian ice sheet was cold-based in its central areas during its maximum. During the deglaciation, both the dry/wet-base boundary and ice margin migrated inwards, at different speeds. When the ice front retreated faster than the thermal transition zone, the wet-base marginal zone shrank and erosion was reduced or avoided. Where the wet-base zone was of limited longitudinal extent, as on the Ultevis plateau, conversion from a frozen to a thawed bed was incomplete, leaving a patchwork of preserved glacial and non-glacial morphologies.

scholarly journals Late Weichselian thermal state at the base of the Scandinavian Ice Sheet

2019 ◽  
Author(s):  
Dmitry Y. Demezhko ◽  
Anastasia A. Gornostaeva ◽  
Alexander N. Antipin
Keyword(s):  
Thermal State ◽  
Ice Sheet ◽  
Ground Surface ◽  
Substantial Part ◽  
Temperature Pattern ◽  
Glacial Cycle ◽  
Surface Temperatures ◽  
Scandinavian Ice Sheet ◽  
Late Weichselian ◽  
The Last Glacial

Abstract. Geothermal estimates of the ground surface temperatures for the last glacial cycle in Northern Europe has been analyzed. During the Middle and Late Weichselian (55–12 kyr BP) a substantial part of this area was covered by the Scandinavian Ice Sheet. The analysis of geothermal data has allowed reconstructing limits of the ice sheet extension and its basal thermal state in the Late Weichselian. Ground surface temperatures outside the ice sheet were extremely low (from −8 to −18 °C). Within the ice sheet, there were both thawed and frozen zones. The revealed temperature pattern is generally consistent with the modern one for the ground surface temperatures in Greenland that makes it possible to consider these ice sheets as analogues. The anomalous climatically induced surface heat flux and orbital insolation of the Earth varied consistently outside the glaciation and independently within the limits of the ice sheet.

Extent and Dynamics of the Scandinavian Ice Sheet during Oxygen Isotope Stage 3 (65,000–25,000 yr B.P.)

2002 ◽  
Vol 57 (1) ◽  
pp. 38-48 ◽  
Author(s):  
Neil S. Arnold ◽  
Tjeerd H. van Andel ◽  
Vidar Valen
Keyword(s):  
Sea Ice ◽  
Oxygen Isotope ◽  
Ice Sheet ◽  
Ice Cover ◽  
Glacial Maximum ◽  
Oxygen Isotope Stage ◽  
Free Interval ◽  
Scandinavian Ice Sheet ◽  
Weichselian Glaciation ◽  
Low Precipitation

AbstractThe climate of the middle Weichselian Glaciation, Marine Oxygen Isotope Stage 3 (OIS-3), a relatively mild period compared to the glacial maxima of OIS-4 and OIS-2, consisted of long warm interstades punctuated by brief cold excursions that grew colder and more frequent with time. The OIS-4 ice sheet is generally thought to have persisted throughout OIS-3, but evidence from dated OIS-3 interstadial deposits suggests that it was swiftly reduced to small remnants which only briefly expanded and retreated. Only 30,000 years ago the deteriorating climate initiated a sustained ice advance leading toward the final glacial maximum of OIS-2. Dynamic ice-sheet models support the existence of a prolonged ice-free interval during OIS-3 induced, perhaps, by low precipitation due to extensive sea-ice cover offshore.

scholarly journals Genesis of the glaciotectonic thrust-fault complex at Halk Hoved, southern Denmark.

2012 ◽  
Vol 60 ◽  
pp. 61-80
Author(s):  
Tillie M. Madsen
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Ice Sheet ◽  
Thrust Fault ◽  
Complex Deformation ◽  
North East ◽  
Macro Scale ◽  
Scandinavian Ice Sheet ◽  
Late Weichselian ◽  
Southern Fringe

The coastal cliff of Halk Hoved, southern Jutland, Denmark, is a major glaciotectonic complex formed by proglacial deformation of the North-East (NE) advance from the Scandinavian Ice Sheet in Late Weichselian. We describe and interpret the pre-, syn- and post-tectonic sedimentary successions and macro-scale architecture of this complex. Initially, the Lillebælt Till Formation (unit 1) and the overlying glaciofluvial sediments (unit 2) were deposited during the Warthe glaciation in Late Saalian. During the NE advance towards the Main Stationary Line (MSL) in Late Weichselian, these sediments were pushed along a décollement surface whereby a thrust-fault complex was formed. In a cross section the complex extends for more than 900 m and consists of eighteen c. 15–20 m thick thrust sheets stacked by piggyback thrusting. Accumulated displacement amounts to at least 235 m along thrust faults dipping at 30–40° towards N-NE, resulting in at least 24% glaciotectonic shortening of the complex. Deformation was presumably facilitated by elevated pore-water pressure in the Lillebælt Till Formation. As the compressive stress exceeded the shear strength of the weakened till, failure occurred, and a décollement horizon formed along the lithological boundary between the Lillebælt Till Formation and the underlying aquifer. During deformation, piggyback basins formed wherein sediments of hyperconcentrated flow (unit 3) and glaciolacustrine diamicton (unit 4) were deposited. The whole thrust-fault complex and the intervening sediments were truncated subglacially as the NE advance finally overrode the complex. Following the retreat of the NE advance, a succession of glaciofluvial sediments (unit 5) and finally the East Jylland Till Formation (unit 6) were deposited during the advance of the Young Baltic Ice Sheet. The Halk Hoved thrust-fault complex is a prominent example of glaciotectonism at the southern fringe of the Scandinavian Ice Sheet.

scholarly journals Thickness evolution of the Scandinavian Ice Sheet during the Late Weichselian in Nordfjord, western Norway: evidence from ice-flow modeling

Boreas ◽  
2005 ◽  
Vol 34 (2) ◽  
pp. 176-185 ◽  
Author(s):  
Cornelia Winguth ◽  
David Mickelson ◽  
Eiliv Larsen ◽  
Jessica Darter ◽  
Carolyn Moeller ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Flow Modeling ◽  
Ice Flow ◽  
Western Norway ◽  
Scandinavian Ice Sheet ◽  
Late Weichselian

Numerical Modeling of the Late Weichselian Svalbard-Barents Sea Ice Sheet

1995 ◽  
Vol 43 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Martin J. Siegert ◽  
Julian A. Dowdeswell
Keyword(s):  
Numerical Model ◽  
Sea Ice ◽  
Barents Sea ◽  
Ice Sheet ◽  
Ice Cover ◽  
Time Dependent ◽  
Southern Limit ◽  
Geological Evidence ◽  
Iceberg Calving ◽  
Late Weichselian

AbstractPrevious reconstructions of the ice cover of the Svalbard-Barents Sea region during the late Weichselian have ranged from small ice masses on Svalbard to complete inundation of the Barents Shelf region by an ice sheet several kilometers thick. We have used a time-dependent finite-difference numerical model to undertake a new glaciological reconstruction for the Svalbard-Barents Sea Ice Sheet over the last 30,000 yr. The numerical model requires environmental forcing functions in the form of air temperature and precipitation and their behavior with respect to altitude, together with sea-level change and an iceberg calving relation. Ice buildup on Svalbard is calculated to have begun 28,000 yr ago, and maximum dimensions were reached by 20,000 yr ago, covering Svalbard and the northwestern Barents Sea with a center of mass (1.3 km thick) around eastern Svalbard. Decay was complete by about 10,000 yr ago. The margin of the modeled ice sheet at its maximum is in good agreement with observed sea-floor morphological features, but there are discrepancies in timing between the modeled ice sheet decay and (i) a dated meltwater spike in Fram Strait and (ii) the observed rebound curves for Svalbard. An inverse approach was used to predict ice sheet decay, and it was found that increasing the rate of iceberg calving within the model produces a deglaciation some 2000 yr earlier, which is compatible with these two independent datasets. The reconstruction is also compatible with geological evidence on the isostatic response of Bjørnøya, close to the southern limit of the ice sheet, and seismically observed deposits, interpreted to be ice. proximal facies, located in the northwestern Barents Sea. Our time-dependent model reconstructions of the Svalbard-Barents Sea Ice Sheet indicate ice cover over only the northwestern Barents Sea during the late Weichselian, but this does not preclude the presence of ice derived from Fennoscandia and the Kara Sea region elsewhere in the Barents Sea.

scholarly journals Modelling Late Weichselian evolution of the Eurasian ice sheets forced by surface meltwater-enhanced basal sliding

2014 ◽  
Vol 60 (219) ◽  
pp. 29-40 ◽  
Author(s):  
C.C. Clason ◽  
P.J. Applegate ◽  
P. Holmlund
Keyword(s):  
Ice Sheets ◽  
Ice Sheet ◽  
Ice Streams ◽  
Ice Volume ◽  
Ice Surface ◽  
Scandinavian Ice Sheet ◽  
Basal Sliding ◽  
Late Weichselian ◽  
The Baltic ◽  
Fast Flow

AbstractWe simulated the Late Weichselian extent and dynamics of the Eurasian ice sheets using the shallow-ice approximation ice-sheet model SICOPOLIS. Our simulated Last Glacial Maximum ice-sheet extents closely resemble geomorphological reconstructions, and areas of modelled fast flow are consistent with the known locations of palaeo-ice streams. Motivated by documented velocity response to increased meltwater inputs on Greenland, we tested the sensitivity of the simulated ice sheet to the surface meltwater effect (SME) through a simple parameterization relating basal sliding to local surface melt rate and ice thickness. Model runs including the SME produce significantly reduced ice volume during deglaciation, with maximum ice surface velocities much greater than in similar runs that neglect the SME. We find that the simple treatment of the SME is not applicable across the whole ice sheet; however, our results highlight the importance of the SME for dynamic response to increased melting. The southwest sector of the Scandinavian ice sheet is most sensitive to the SME, with fast flow in the Baltic ice stream region shutting off by 15 ka BP when the SME is turned on, coincident with a retreat of the ice-margin position into the Gulf of Bothnia.

scholarly journals Thickness evolution of the Scandinavian Ice Sheet during the Late Weichselian in Nordfjord, western Norway: evidence from ice-flow modeling

Boreas ◽  
2008 ◽  
Vol 34 (2) ◽  
pp. 176-185 ◽  
Author(s):  
CORNELIA WINGUTH ◽  
DAVID M. MICKELSON ◽  
EILIV LARSEN ◽  
JESSICA R. DARTER ◽  
CAROLYN A. MOELLER ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Flow Modeling ◽  
Ice Flow ◽  
Western Norway ◽  
Scandinavian Ice Sheet ◽  
Late Weichselian
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