Paleofluvial landscape inheritance for Jakobshavn Isbræ catchment, Greenland

Subglacial topography exerts strong controls on glacier dynamics, influencing the orientation and velocity of ice flow, as well as modulating the distribution of basal waters and sediment. Bed geometry can also provide a long‐term record of geomorphic processes, allowing insight into landscape evolu...

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Bibliographic Details
Published in:Geophysical research letters 2016-06, Vol.43 (12), p.6350-6357
Main Authors: Cooper, M. A., Michaelides, K., Siegert, M. J., Bamber, J. L.
Format: Article
Language:English
Subjects:
Banks (topography)
Basins
Bedrock
Catchment area
Catchments
Drainage
Drainage basins
Drainage network
Drainage patterns
Dynamics
Evolution
fluvial erosion
Geomorphology
Geophysics
Glacial dynamics
glacial erosion
Glaciation
Glacier size
Glaciers
Glaciohydrology
Greenland ice sheet
Heredity
Ice
Ice formation
Ice sheets
Landscape
landscape inheritance
Landscapes
Morphometry
Orientation
Origins
Outlets
paleofluvial origin
Radar
Radar data
Sea level
Slope
Subglacial topography
Topography
Topography (geology)
Velocity
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Summary:Subglacial topography exerts strong controls on glacier dynamics, influencing the orientation and velocity of ice flow, as well as modulating the distribution of basal waters and sediment. Bed geometry can also provide a long‐term record of geomorphic processes, allowing insight into landscape evolution, the origin of which may predate ice sheet inception. Here we present evidence from ice‐penetrating radar data for a large dendritic drainage network, radiating inland from Jakobshavn Isbræ, Greenland's largest outlet glacier. The size of the drainage basin is ∼450,000 km2 and accounts for about 20% of the total land area of Greenland. Topographic and basin morphometric analyses of an isostatically uplifted (ice‐free) bedrock topography suggests that this catchment predates ice sheet initiation and has likely been instrumental in controlling the location and form of the Jakobshavn ice stream, and ice flow from the deep interior to the margin, now and over several glacial cycles. Key Points Evidence for an extensive dendritic basin beneath the Greenland ice sheet's largest outlet glacier Analysis suggests a paleofluvial landscape origin, predating ice sheet inception The ancient landscape retains an influence on contemporary glacial processes
ISSN:0094-8276
1944-8007
DOI:10.1002/2016GL069458