GIS dataset: geomorphological record of terrestrial-terminating ice streams,  southern sector of the Baltic Ice Stream  Complex, last Scandinavian Ice Sheet, Poland

Abstract. Here we present a comprehensive dataset of glacial geomorphological features covering an area of 65 000 km2 in central west Poland, located along the southern sector of the last Scandinavian Ice Sheet, within the limits of the Baltic Ice Stream Complex. The GIS dataset is based on mapping from a 0.4 m high-resolution digital elevation model derived from airborne light detection and ranging data. Ten landform types have been mapped: mega-scale glacial lineations, drumlins, marginal features (moraine chains, abrupt margins, edges of ice-contact fans), ribbed moraines, tunnel valleys, eskers, geometrical ridge networks, and hill–hole pairs. The map comprises 5461 individual landforms or landform parts, which are available as vector layers in GeoPackage format at https://doi.org/10.5281/zenodo.4570570 (Szuman et al., 2021a). These features constitute a valuable data source for reconstructing and modelling the last Scandinavian Ice Sheet extent and dynamics from the Middle Weichselian Scandinavian Ice Sheet advance, 50–30 ka, through the Last Glacial Maximum, 25–21 ka, and Young Baltic advances, 18–15 ka. The presented data are particularly useful for modellers, geomorphologists, and glaciologists.

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GIS dataset: geomorphological record of terrestrial-terminating ice streams, southern sector of Baltic Ice Stream Complex, last Scandinavian Ice Sheet, Poland

10.5194/essd-2021-59 ◽

2021 ◽

Author(s):

Izabela Szuman ◽

Jakub Z. Kalita ◽

Marek W. Ewertowski ◽

Chris D. Clark ◽

Stephen J. Livingstone ◽

...

Keyword(s):

Ice Sheet ◽

Ice Streams ◽

Southern Sector ◽

Ice Stream ◽

Digital Elevation ◽

Scandinavian Ice Sheet ◽

Data Source ◽

Elevation Model ◽

The Baltic ◽

The Last Glacial

Abstract. Here we present a comprehensive dataset of glacial geomorphological features covering an area of 65 000 km2 in central west Poland, located along the southern sector of the last Scandinavian Ice Sheet, within the limits of the Baltic Ice Stream Complex. The GIS dataset is based on mapping from a 0.4 m high-resolution Digital Elevation Model derived from airborne Light Detection and Ranging data. Ten landform types have been mapped: Mega-Scale Glacial Lineations, drumlins, marginal features (moraine chains, abrupt margins, edges of ice-contact fans), ribbed moraines, tunnel valleys, eskers, geometrical ridge networks and hill-hole pairs. The map comprises 5461 individual landforms or landform parts, which are available as vector layers in GeoPackage format at http://doi.org/10.5281/zenodo.4570570 (Szuman et al., 2021a). These features constitute a valuable data source for reconstructing and modelling the last Scandinavian Ice Sheet extent and dynamics from the Middle Weichselian Scandinavian Ice Sheet advance, 50–30 ka BP, through the Last Glacial Maximum, 25–21 ka BP and Young Baltic Advances, 18–15 ka BP. The presented data are particularly useful for modellers, geomorphologists and glaciologists.

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Dynamics of the last Scandinavian Ice Sheet’s southernmost sector revealed by the pattern of ice streams

10.5194/egusphere-egu21-975 ◽

2021 ◽

Author(s):

Izabela Szuman ◽

Jakub Z. Kalita ◽

Marek W. Ewertowski ◽

Chris D. Clark ◽

Stephen J. Livingstone

Keyword(s):

Ice Sheet ◽

Ice Streams ◽

Climatic Forcing ◽

Ice Dynamics ◽

Geomorphological Mapping ◽

Ice Stream ◽

Digital Elevation ◽

Scandinavian Ice Sheet ◽

Ice Sheet Dynamics ◽

Elevation Model

The Polish sector of the last Scandinavian Ice Sheet is a key area for studying ice sheet drainage and decay from its local Last Glacial Maximum (LGM) extent, as it is located at the terrestrial terminus of the large and dynamic Baltic Ice Stream Complex. Geomorphological mapping, based on a 0.4 m LIDAR digital elevation model, revealed about 940 streamlined bedforms, many of which are shown for the first time and consisting of mega-scale glacial lineations and drumlins. The lineation flow-sets together with associated landforms were used to identify seventeen ice streams, occupying 80% of the study area. We demonstrated that subtle topographic variations played an important role in influencing ice sheet dynamics. Variations in ice dynamics were a response to external climatic forcing that controlled deglaciation at the ice sheet scale as well as internal reorganisation due to the influence of topography, subglacial hydrology and glacier thermal regime. During the local LGM, the southern sector of the Scandinavian Ice Sheet in Poland was dominated by four simultaneously operating ice streams, likely active for several millennia, followed by fast active recession interrupted by three main periods of ice stream stagnation. Increased ice flowdynamics during the period of the Young Baltic advances is suggested to be caused by variations in subglacial hydrology and the polythermal structure of the ice sheet.&#160;

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Thermomechanical modelling of the Scandinavian ice sheet: implications for ice-stream formation

Annals of Glaciology ◽

10.3189/172756499781821733 ◽

1999 ◽

Vol 28 ◽

pp. 83-89 ◽

Cited By ~ 28

Author(s):

A. J. Payne ◽

D.J. Baldwin

Keyword(s):

Three Dimensional ◽

Ice Sheet ◽

Ice Streams ◽

Ice Flow ◽

Low Viscosity ◽

Ice Stream ◽

Scandinavian Ice Sheet ◽

The Baltic ◽

Stream Formation ◽

Initial Results

AbstractThis work attempts to explain the fan-like landform assemblages observed in satellite images of the area covered by the former Scandinavian ice sheet (SIS). These assemblages have been interpreted as evidence of large ice streams within the SIS. If this interpretation is correct, then it calls into doubt current theories on the formation of ice streams. These theories regard soft sediment and topographic troughs as being the key determinants of ice-stream location. Neither can be used to explain the existence of ice streams on the flat, hard-rock area of the Baltic Shield. Initial results from a three-dimensional, thermomechanical ice-sheet model indicate that interactions between ice flow, form and temperature can create patterns similar to those mentioned above. The model uses a realistic, 20 km resolution gridded topography and a simple parameterization of accumulation and ablation. It produces patterns of maximum ice-sheet extent, which are similar to those reconstructed from the area’s glacial geomorphology. Flow in the maximum, equilibrium ice sheet is dominated by wedges of warm, low-viscosity, fast-flowing ice. These are separated by areas of cold, slow-flowing ice. This patterning appears to develop spontaneously as the modelled ice sheet grows.

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Asynchronous instability of NE ice streams of the Laurentide Ice Sheet recorded in the marine sediments of Labrador Sea during the last glacial cycle

10.5194/egusphere-egu2020-6774 ◽

2020 ◽

Author(s):

Harunur Rashid ◽

Mary Smith ◽

Min Zeng ◽

Yang Wang ◽

Julie Drapeau ◽

...

Keyword(s):

Ice Sheet ◽

Laurentide Ice Sheet ◽

Labrador Sea ◽

Glacial Cycle ◽

Ice Streams ◽

Last Glacial ◽

Ice Stream ◽

Cumberland Sound ◽

Detrital Carbonate ◽

The Last Glacial

Hughes et al. (1977) hypothesized of a pan-Arctic Ice Sheet that behaved as a single dynamic system during the Last Glacial Maximum. Moreover, the authors suggested a nearly grounded ice shelf in Davis Strait implying that little or no exchange between Baffin Island and the Labrador Sea. Here we present data at 1-cm (<100 years) resolution between ~12 ka and 45 ka that shed light on the discharge from Hudson Strait and Lancaster Sound ice streams of the Late Pleistocene Laurentide Ice Sheet. A reference sediment core at 938 m water depth on the SE Baffin Slope was investigated with new oxygen isotope stratigraphy, X-ray fluorescence geochemistry, and 18 14C-AMS dates and correlated to 14 regional deep-water cores. Detrital carbonate-rich sediment layers H0-H4 were derived principally from Hudson Strait. Shortly after H2 and H3, the shelf-crossing Cumberland Sound ice stream supplied dark brown ice-proximal stratified sediments but no glacigenic debris-flow deposits. The counterparts of H3, H4, and (?)H5 events in the deep Labrador basin are 4&#8211;10 m thick units of thin-bedded carbonate-rich mud turbidites from glacigenic debris flows on the Hudson Strait slope. The behavior of the Hudson Strait ice stream changed through the last glacial cycle. The Hudson Strait ice stream remained at the shelf break in H3-H5 but retreated rapidly across the shelf in H0-H2 and did not deglaciate Hudson Bay. During this time, Cumberland Sound ice twice reached the shelf edge. In H3&#8211;H5, it remained at the shelf break long enough to supply thick turbidites. Minor supply of carbonate-rich sediment from Baffin Bay allows chronologic integration of the Baffin Bay and Labrador Sea detrital carbonate records, which is diachronous with respect to Heinrich events. The asynchrony of the carbonate events implies an open seaway through Davis Strait. Our data suggest that the maximum extent of ice streams in Hudson Strait, Cumberland Sound, and Lancaster Sound was neither synchronous.

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Signature and timing of the Kattegat Ice Stream: onset of the Last Glacial Maximum sequence at the southwestern margin of the Scandinavian Ice Sheet

Boreas ◽

10.1111/j.1502-3885.2003.tb01439.x ◽

2003 ◽

Vol 32 (1) ◽

pp. 227-241 ◽

Cited By ~ 36

Author(s):

MICHAEL HOUMARK-NIELSEN

Keyword(s):

Last Glacial Maximum ◽

Ice Sheet ◽

Glacial Maximum ◽

Last Glacial ◽

Ice Stream ◽

Scandinavian Ice Sheet ◽

Southwestern Margin ◽

Maximum Sequence ◽

The Last Glacial Maximum ◽

The Last Glacial

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

Journal of Glaciology ◽

10.3189/2014jog13j037 ◽

2014 ◽

Vol 60 (219) ◽

pp. 29-40 ◽

Cited By ~ 17

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.

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Ice-flow patterns and dispersal of erratics at the southwestern margin of the last Scandinavian Ice Sheet: signature of palaeo-ice streams

Boreas ◽

10.1080/03009480310001074 ◽

2003 ◽

Vol 32 (1) ◽

pp. 130-148 ◽

Cited By ~ 1

Author(s):

KURT H. KJÆR ◽

MICHAEL HOUMARK-NIELSEN ◽

NIELS RICHARDT

Keyword(s):

Ice Sheet ◽

Flow Patterns ◽

Ice Streams ◽

Ice Flow ◽

Scandinavian Ice Sheet ◽

Southwestern Margin

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Drivers of abrupt Holocene shifts in West Antarctic ice stream direction determined from combined ice sheet modelling and geologic signatures

Antarctic Science ◽

10.1017/s0954102014000613 ◽

2014 ◽

Vol 26 (6) ◽

pp. 674-686 ◽

Cited By ~ 16

Author(s):

C.J. Fogwill ◽

C.S.M. Turney ◽

N.R. Golledge ◽

D.H. Rood ◽

K. Hippe ◽

...

Keyword(s):

Flow Direction ◽

Ice Sheet ◽

Weddell Sea ◽

Last Deglaciation ◽

Ice Streams ◽

Antarctic Ice Sheet ◽

West Antarctic Ice Sheet ◽

West Antarctic ◽

Ice Stream ◽

Ice Sheet Modelling

AbstractDetermining the millennial-scale behaviour of marine-based sectors of the West Antarctic Ice Sheet (WAIS) is critical to improve predictions of the future contribution of Antarctica to sea level rise. Here high-resolution ice sheet modelling was combined with new terrestrial geological constraints (in situ14C and 10Be analysis) to reconstruct the evolution of two major ice streams entering the Weddell Sea over 20 000 years. The results demonstrate how marked differences in ice flux at the marine margin of the expanded Antarctic ice sheet led to a major reorganization of ice streams in the Weddell Sea during the last deglaciation, resulting in the eastward migration of the Institute Ice Stream, triggering a significant regional change in ice sheet mass balance during the early to mid Holocene. The findings highlight how spatial variability in ice flow can cause marked changes in the pattern, flux and flow direction of ice streams on millennial timescales in this marine ice sheet setting. Given that this sector of the WAIS is assumed to be sensitive to ocean-forced instability and may be influenced by predicted twenty-first century ocean warming, our ability to model and predict abrupt and extensive ice stream diversions is key to a realistic assessment of future ice sheet sensitivity.

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Of isbræ and ice streams

Annals of Glaciology ◽

10.3189/172756403781816347 ◽

2003 ◽

Vol 36 ◽

pp. 66-72 ◽

Cited By ~ 88

Author(s):

Martin Truffer ◽

Keith A. Echelmeyer

Keyword(s):

Ice Sheet ◽

Shear Zones ◽

West Antarctica ◽

Ice Streams ◽

Ice Flow ◽

Bed Topography ◽

Ice Stream ◽

Fast Ice ◽

Fast Flow ◽

End Members

AbstractFast-flowing ice streams and outlet glaciers provide the major avenues for ice flow from past and present ice sheets. These ice streams move faster than the surrounding ice sheet by a factor of 100 or more. Several mechanisms for fast ice-stream flow have been identified, leading to a spectrum of different ice-stream types. In this paper we discuss the two end members of this spectrum, which we term the “ice-stream” type (represented by the Siple Coast ice streams in West Antarctica) and the “isbræ” type (represented by Jakobshavn Isbræ in Greenland). The typical ice stream is wide, relatively shallow (∼1000 m), has a low surface slope and driving stress (∼10 kPa), and ice-stream location is not strongly controlled by bed topography. Fast flow is possible because the ice stream has a slippery bed, possibly underlain by weak, actively deforming sediments. The marginal shear zones are narrow and support most of the driving stress, and the ice deforms almost exclusively by transverse shear. The margins seem to be inherently unstable; they migrate, and there are plausible mechanisms for such ice streams to shut down. The isbræ type of ice stream is characterized by very high driving stresses, often exceeding 200 kPa. They flow through deep bedrock channels that are significantly deeper than the surrounding ice, and have steep surface slopes. Ice deformation includes vertical as well as lateral shear, and basal motion need not contribute significantly to the overall motion. The marginal shear zone stend to be wide relative to the isbræ width, and the location of isbræ and its margins is strongly controlled by bedrock topography. They are stable features, and can only shut down if the high ice flux cannot be supplied from the adjacent ice sheet. Isbræs occur in Greenland and East Antarctica, and possibly parts of Pine Island and Thwaites Glaciers, West Antarctica. In this paper, we compare and contrast the two types of ice streams, addressing questions such as ice deformation, basal motion, subglacial hydrology, seasonality of ice flow, and stability of the ice streams.

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