Numerical modelling provides evidence of a Baltic Ice Stream during the Younger Dryas

AbstractA network of relatively fast-flowing tributaries in the catchment basins of the West Antarctic ice streams transport ice from the inland reservoir to the heads of the ice streams. Branches of the network follow valleys in basal topography but not all valleys contain tributaries. We investigate the circumstances favoring tributary flow upstream of Ice Streams D and E, using a combination of observation and numerical modelling. No consistent pattern emerges. The transition from tributary to ice-stream flow occurs smoothly along the main tributary feeding into the onset of Ice Stream D, with ice thickness being relatively more important upstream, and sliding being relatively more important downstream. Elsewhere, the downstream pattern of flow is more complicated, with local increases and decreases in the contribution of sliding to ice speed. Those changes may be due to variations in basal water storage, subglacial geologic properties or a combination of the two.

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Hudson Strait ice dam collapse: An explanation for the onset of the Younger Dryas cold climate in Europe in only one year

JOURNAL OF ADVANCES IN NATURAL SCIENCES ◽

10.24297/jns.v18i.8961 ◽

2021 ◽

Vol 18 ◽

pp. 1-11

Author(s):

Robert Glenn Johnson

Keyword(s):

Stream Flow ◽

Younger Dryas ◽

Cold Climate ◽

Hudson Bay ◽

Glacial Ice ◽

Ice Stream ◽

Climate Event ◽

Southern Half ◽

East End ◽

One Year

The Younger Dryas cold climate event in Europe began abruptly at about 12,679 years BP. The abruptness of the onset was caused by the rapid collapse of a dynamic ice dam that had existed because of ice stream flow across the east end of Hudson Strait in northern Canada. The resulting flood of icebergs into the southern half of the Northern Gyre adjacent to the Gulf Stream converted western Europe’s mild climate to an arctic climate. The collapse event was caused by the last large accumulation of glacial ice in the thick ice dome of Hudson Bay. The accumulation created a pressure gradient that forced an ice stream flow eastward in Hudson Strait. A highly saline sub-glacial lake had formed earlier in the western part of the strait. The ice stream flow entrained saline lake water in a network of channels at the seabed between the lake and the ice dam, melting and extending the network eventually to and beneath the ice dam. This detached much of the ice dam from its frozen bed and caused its catastrophic collapse and the onset of the Younger Dryas in only one year.

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A combined numerical modelling and mapping approach to the reconstructing of Younger Dryas Stadial glaciers in the South-West English Lake District

Quaternary International ◽

10.1016/j.quaint.2012.08.1807 ◽

2012 ◽

Vol 279-280 ◽

pp. 521

Author(s):

Andreas Vieli

Keyword(s):

Numerical Modelling ◽

Younger Dryas ◽

Lake District ◽

The South ◽

South West ◽

Mapping Approach ◽

English Lake District

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The role of ice thickness and bed properties on the dynamics of the enhanced-flow tributaries of Bailey Ice Stream and Slessor Glacier, East Antarctica

Annals of Glaciology ◽

10.3189/172756404781814375 ◽

2004 ◽

Vol 39 ◽

pp. 366-372 ◽

Cited By ~ 15

Author(s):

David M. Rippin ◽

Jonathan L. Bamber ◽

Martin J. Siegert ◽

David G. Vaughan ◽

Hugh F. J. Corr

Keyword(s):

Numerical Modelling ◽

Significant Proportion ◽

East Antarctica ◽

Ice Thickness ◽

Ice Stream ◽

Radio Echo Sounding ◽

Basal Reflection ◽

Echo Sounding ◽

Modelling Study

AbstractAirborne radio-echo sounding investigations in the upper reaches of Bailey Ice Stream and Slessor Glacier, Coats Land, East Antarctica, have shown that enhanced-flow tributaries are associated with well-defined areas of relatively thicker ice, and are separated from each other by areas of relatively thinner ice. A numerical modelling study has revealed that while internal ice deformation might account for all the observed flow in inter-tributary areas and the majority in the Slessor tributaries, a significant proportion of the flow of Bailey tributary is attributable to basal motion. Further, investigations of depth-corrected basal reflection power indicate that the bed underlying both Bailey and Slessor enhanced-flow tributaries is significantly smoother than in the slower-moving inter-tributary areas. It is thus proposed that enhanced motion within Bailey tributary (and also perhaps Slessor) may be facilitated by a reduction in basal roughness, caused by the accumulation of water and/or sediments within subglacial valleys, or by the erosion and smoothing of bed obstacles.

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