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

Boreas - Tập 42 Số 1 - Trang 84-107 - 2013
Lilja Rún Bjarnadóttir1, Denise Christina Rüther1, Monica Winsborrow1, Karin Andreassen1
1Department of Geology University of Tromsø Dramsveien 201 N‐9037 Tromsø Norway

Tóm tắt

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 fine‐grained 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.

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Boreas

Tập 42 Số 1

84-107

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