Abstract Glacial landforms, in particular flutes and associated transverse ridges, have been identified in an area of roughly 4000 km 2 and between approximately 150 and 340 m water depth in the north-central Barents Sea. The transverse ridges are interpreted to be analogous to De Geer moraines and are observed only in the southern part of the fluted area. The flutes, trending roughly north-south, have a relief of less than one metre, widths on the order of 4–8 m and lengths usually 100–500 m. Although the present data do not allow firm conclusions on the exact genesis of these features, they are compared to analogous terrestrial features. The existence of these glacigenic morphological features has major implications concerning the late glacial history of the Barents Sea. They give the first direct evidence of a grounded ice sheet in the northern Barents Sea. Ice flow directions during the latest phase before final recession were mainly southwards, but a partly topographically influenced flow pattern indicates that the main banks may have acted as local ice centres. The ice sheet was relatively thin and rested on a deformable bed. It retreated rapidly from the fluted area, as evidenced by the lack of sediment masking the low-relief flutes. The general retreat from the region took place in a stepwise manner, apparently without surging and with deposition of locally thicker glacier-proximal deposits during halts in the recession.
The seabed morphology beneath the ice shelf is dominated by a slope down towards the interior of the continent. Deep troughs, possibly glacially deepened, run beneath the eastern and weatern sides of the ice shelf and cross the continental shelf. An area of small water column thickness to the north-west of Berkner Island suggests that extensive grounding could occur after a relatively small change in the ice shelf
Site 986 was drilled to 965 meters below seafloor (mbsf) on the western Svalbard margin to record the onset of glaciations and to date and document the glacial evolution in the Svalbard‐Barents Sea region during the Pliocene‐Pleistocene. In this paper, results of sedimentological analyses are discussed in light of seismic stratigraphy and new age determinations. The latt er were difficult to obtain in the glacial deposits, and datums are sparse. Through combined paleomagnetic data, biostratigraphy, and Sr isotopes, however, an overall chronology for the main evolutionary steps is suggested. The cored sequence at Site 986 is younger than 2.6 Ma, and the lower 60 m of the section contains no evidence of a major glacial influence. An initial glaciation is interpreted to have occurred at ~2.3 Ma, resulting in increased sand deposition from debris flows at Site 986 and forming a prominent seismic reflector, R7. However, glaciers probably did not reach the shelf break until ~1.6‐1.7 Ma (Reflector R6), after which the depositional environment was dominated by diamictic debris flows. A gradual change in source area from the Barents Sea to Svalbard is recorded primarily by changes in carbonate and smectite content, ~355 mbsf (Reflector R5), at an interpolated age of 1.4‐1.5 Ma. During the last ~1 m.y., Site 986 has undergone more distal deposition as the main depocenters have shifted laterally. This has resulted in less frequent debris flows and more turbidites and hemipelagic deposits, with a sl ight fining upward of the cored sediments.
This paper discusses the influence of sedimentary environment and geological setting on geotechnical and physical properties of resulting sedimentary deposits. For this study, two different geological settings were considered, one is a river-fed and the other is a glacier-fed sedimentary environment. For both sedimentary environments, various geotechnical properties were considered and compared. These include plasticity, activity, compressibility, undrained shear strength and sensitivity. Results indicate that physical and geotechnical properties of sediments deposited in these two settings are significantly different. These differences are then interpreted in terms of the various mechanisms involved in submarine slope failure initiation in river-fed versus glacier-fed sedimentary environments.
Geology and Seismic Stratigraphy of the Antarctic MarginEdited by Alan K. Cooper, Peter F. Barker and Giuliano Brancolini Volume 68, Antarctic Research Series. American Geophysical Union, Washington (1995). 301 pages, atlas (22 plates), 2 CD-ROMs. 45.50). ISBN 0 87590 884 5. - Volume 9 Issue 3
