Postglacial depositional environments and sedimentation rates in the Norwegian Channel off southern Norway

Rise, Leif; Bøe, Reidulv; Ottesen, Dag; Longva, Oddvar; Olsen, Heidi A.

doi:10.1016/j.margeo.2008.02.012

Cited by 17 publications

(15 citation statements)

References 47 publications

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“…years) (Rise et al . ). The outer part of the Norwegian Channel has, on the other hand, also been a depositional area for the last 1.1 million years, allowing for a 300–400 m thick Quaternary unit to accumulate (Fig.…”

Section: Discussionmentioning

confidence: 97%

Quaternary denudation of southern Fennoscandia – evidence from the marine realm

Hjelstuen

Nygård

Sejrup

et al. 2012

Boreas

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Throughout the last 1.1 million years repeated glaciations have modified the southern Fennoscandian landscape and the neighbouring continental shelf into their present form. The glacigenic erosion products derived from the Fennoscandian landmasses were transported to the northern North Sea and the SE Nordic Seas continental margin. The prominent sub‐marine Norwegian Channel trough, along the south coast of Norway, was the main transport route for the erosion products between 1.1 and 0.0 Ma. Most of these erosion products were deposited in the North Sea Fan, which reaches a maximum thickness of 1500 m and has nearly 40 000 km3 of sediments. About 90% of the North Sea Fan sediments have been deposited during the last 500 000 years, in a time period when fast‐moving ice streams occupied the Norwegian Channel during each glacial stage. Back‐stripping the sediment volumes in the northern North Sea and SE Nordic Seas sink areas, including the North Sea Fan, to their assumed Fennoscandian source area gives an average vertical erosion of 164 m for the 1.1–0.0 Ma time period. The average 1.1–0.0 Ma erosion rate in the Fennoscandian source area is estimated to be 0.15 mm a−1. We suggest, however, that large variations in erosion rates have existed through time and that the most intense Fennoscandian landscape denudation occurred during the time period of repeated shelf edge ice advances, namely from Marine Isotope Stage 12 (c. 0.5 Ma) onwards.

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Section: Discussionmentioning

confidence: 97%

Quaternary denudation of southern Fennoscandia – evidence from the marine realm

Hjelstuen

Nygård

Sejrup

et al. 2012

Boreas

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“…Holocene sedimentation is low to absent in BGS 04/01 and in other Witch Ground cores (cf. Rise et al 2008). This observation suggests a shut‐off in sediment transport to the central North Sea basin, with the last c .…”

Section: Discussionmentioning

confidence: 99%

Depositional environments and chronology of Late Weichselian glaciation and deglaciation in the central North Sea

Graham¹,

Lonergan²,

Stoker³

2010

Boreas

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Geological constraints on ice-sheet deglaciation are essential for improving the modelling of ice masses and understanding their potential for future change. Here, we present a detailed interpretation of depositional environments from a new 30-m-long borehole in the central North Sea, with the aim of improving constraints on the history of the marine Late Pleistocene British-Fennoscandian Ice Sheet. Seven units characterize a sequence of compacted and distorted glaciomarine diamictons, which are overlain by interbedded glaciomarine diamictons and soft, bedded to homogeneous marine muds. Through correlation of borehole and 2D/3D seismic observations, we identify three palaeoregimes. These are: a period of advance and ice-sheet overriding; a phase of deglaciation; and a phase of postglacial glaciomarine-to-marine sedimentation. Deformed subglacial sediments correlate with a buried suite of streamlined subglacial bedforms, and indicate overriding by the SE-NW-flowing Witch Ground ice stream. AMS 14 C dating confirms ice-stream activity and extensive glaciation of the North Sea during the Last Glacial Maximum, between c. 30 and 16.2 14 C ka BP. Sediments overlying the ice-compacted deposits have been reworked, but can be used to constrain initial deglaciation to no later than 16.2 14 C ka BP. A re-advance of British ice during the last deglaciation, dated at 13.9 14 C ka BP, delivered ice-proximal deposits to the core site and deposited glaciomarine sediments rapidly during the subsequent retreat. A transition to more temperate marine conditions is clear in lithostratigraphic and seismic records, marked by a regionally pervasive iceberg-ploughmarked erosion surface. The iceberg discharges that formed this horizon are dated to between 13.9 and 12 14 C ka BP, and may correspond to oscillating ice-sheet margins during final, dynamic ice-sheet decay.

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“…1 and 2). The shelfcrossing channel is eroded into relatively soft Mesozoic sedimentary strata that verge onto crystalline rocks near the landward margin (Rise et al, 2008). The frequent occurrence of glacial striae on land show that ice flow was directed almost due west during the maximum ice sheet extent (e.g., Aarseth and Mangerud, 1974;Holtedahl, 1975), but lineations that are recorded on the adjacent sea floor show that the ice flow turned northward and merged with the NCIS a short distance beyond the coastline .…”

Section: Glacial Geologic Setting and Sample Locationsmentioning

confidence: 99%