Grounding‐line dynamics during the last deglaciation of Kveithola, W Barents Sea, as revealed by seabed geomorphology and shallow seismic stratigraphy

Abstract

Andreassen, K. 2013 (January): Grounding-line dynamics during the last deglaciation of Kveithola, W Barents Sea, as revealed by seabed geomorphology and shallow seismic stratigraphy.A marine geophysical study reveals a complex deglaciation pattern in the Kveithola trough, W Barents Sea. The data set includes multibeam swath bathymetry and sub-bottom sediment profiler (chirp) data acquired for the whole extent of a palaeo, marine-terminating ice stream, along with high-resolution single-channel seismic data from chosen profiles. The multibeam data show a geomorphic landform assemblage characteristic of ice streams. The results of a combination of seismic and chirp unit stratigraphy reveal that the seabed geomorphology is governed by a deeper-lying reflector. The reflector dominates surface expressions of several subglacial and ice-marginal units, each connected to a separate episode of ice-margin stillstand/advance. Analysis of the combined data set has resulted in a conceptual model of the ice-stream retreat. The model depicts complex deglaciation of a small, confined ice-stream system through episodic retreat. It describes the formation of several generations of grounding-zone systems, characterized by high meltwater discharges and the deposition of finegrained grounding-line fans. The inferred style of grounding-zone deposition in Kveithola deviates from that of other accounts, and is suggested to be intermediate in the previously described continuum between morainal banks and grounding-line wedges. The results of this paper have implications for grounding-zone theory and should be of interest to modellers of grounding-line dynamics and ice-stream retreat.

Geophysical constraints on the dynamics and retreat of the Barents Sea ice sheet as a paleobenchmark for models of marine ice sheet deglaciation

“…Glacial geomorphology of the seabed reveals that many of the sediments, IRD, and meltwater discharged at the shelf breaks were delivered by ice streams, occupying cross‐shelf troughs [ Batchelor and Dowdeswell , ], that were active during the glacial maximum and deglaciation of the ice sheet [ Ottesen et al ., ; Andreassen et al ., ]. The retreat of these ice streams has since left a complex palimpsest of glacial landforms and sediments, characterized by patterns of nonlinear retreat, switching ice flow, and major readvances [ Ottesen et al ., ; Dowdeswell et al ., ; Winsborrow et al ., , ; Rüther et al ., ; Bjarnadóttir et al ., , ].…”

Glacial landforms and their implications for glacier dynamics in Rijpfjorden and Duvefjorden, northern Nordaustlandet, Svalbard

“…The drainage patterns and deglaciation history in cross‐shelf troughs along the western margin of the former SBIS are relatively well established due to numerous expeditions there (e.g. Andreassen et al ., , ; Landvik et al ., ; Ottesen et al ., , ; Winsborrow et al ., ; Rüther et al ., ; Bjarnadóttir et al ., ; Rebesco et al ., ). Off eastern and northern Svalbard, the drainage patterns and deglaciation history are known only in general terms (e.g.…”

Paleomagnetism and rock magnetism from sediments along a continental shelf-to-slope transect in the NW Barents Sea: Implications for geomagnetic and depositional changes during the past 15 thousand years

“…Caricchi et al Global and Planetary Change 160 (2018) [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] (LGM) (Pedrosa et al, 2011;Rebesco et al, 2011;Rüther et al, 2012;Bjarnadóttir et al, 2013). The E-W trough is relatively small with a length of 90 km from the shelf edge to the eastwards termination, and < 15 km wide.…”