scholarly journals Isostatic uplift in the late Weichselian Barents Sea: implications for ice-sheet growth

1996 ◽  
Vol 23 ◽  
pp. 352-358 ◽  
Author(s):  
M. J. Siegert ◽  
W. Fjeldskaar
Keyword(s):  
Barents Sea ◽  
Ice Sheet ◽  
Time Dependent ◽  
Earth Model ◽  
Novaya Zemlya ◽  
Isostatic Uplift ◽  
Franz Josef Land ◽  
Geological Information ◽  
Ice Loads ◽  
Late Weichselian

Results from a recent time-dependent ice-sheet modelling study of the late Weichselian Svalbard—Barents Sea ice sheet suggest that, under environmental conditions representative of those during the late Weichselian, ice derived solely from Svalbard may have occupied only the relatively shallow (<300 m water depth) northwestern Barents Sea, with other deeper regions remaining free of grounded ice (Siegert and Dowdeswell, 1995a). However, late Weichselian geological information from the 400 m deep Bjørnøyrenna (southern Barents Sea) indicates that grounded ice was present in an area modelled by Siegert and Dowdeswell (1995a) as free of ice (e.g. Laberg and Vorren, in press a). Isostatic uplift of the central Barents Sea may have reduced the relative sea level and hence provided a mechanism by which grounded ice could have migrated from relatively shallow regions of the Barents Sea into, previous to uplift, deeper water. We have used an isostatic Earth model to determine the geometry of an isostatic forebulge within the late Weichselian Barents Sea, caused by ice loads over Svalbard, Franz Josef Land, Novaya Zemlya and Fennoscandia. These data were then used as input to a time-dependent glaciological model, in order to predict further information about the magnitude of bedrock uplift required to allow grounded ice to flow from Svalbard into the central and southern Barents Sea. Our experiments suggest that grounded ice, originating from Svalbard, is able to form over Sentralbanken, providing that at least 60 m of uplift is achieved in the central Barents Sea. Grounded ice within Bjørnøyrenna was only predicted when the amplitude of the local forebulge exceeded 250 m.

scholarly journals Isostatic uplift in the late Weichselian Barents Sea: implications for ice-sheet growth

1996 ◽  
Vol 23 ◽  
pp. 352-358
Author(s):  
M. J. Siegert ◽  
W. Fjeldskaar
Keyword(s):  
Barents Sea ◽  
Ice Sheet ◽  
Time Dependent ◽  
Earth Model ◽  
Novaya Zemlya ◽  
Isostatic Uplift ◽  
Franz Josef Land ◽  
Geological Information ◽  
Ice Loads ◽  
Late Weichselian

Results from a recent time-dependent ice-sheet modelling study of the late Weichselian Svalbard—Barents Sea ice sheet suggest that, under environmental conditions representative of those during the late Weichselian, ice derived solely from Svalbard may have occupied only the relatively shallow (<300 m water depth) northwestern Barents Sea, with other deeper regions remaining free of grounded ice (Siegert and Dowdeswell, 1995a). However, late Weichselian geological information from the 400 m deep Bjørnøyrenna (southern Barents Sea) indicates that grounded ice was present in an area modelled by Siegert and Dowdeswell (1995a) as free of ice (e.g. Laberg and Vorren, in press a). Isostatic uplift of the central Barents Sea may have reduced the relative sea level and hence provided a mechanism by which grounded ice could have migrated from relatively shallow regions of the Barents Sea into, previous to uplift, deeper water. We have used an isostatic Earth model to determine the geometry of an isostatic forebulge within the late Weichselian Barents Sea, caused by ice loads over Svalbard, Franz Josef Land, Novaya Zemlya and Fennoscandia. These data were then used as input to a time-dependent glaciological model, in order to predict further information about the magnitude of bedrock uplift required to allow grounded ice to flow from Svalbard into the central and southern Barents Sea. Our experiments suggest that grounded ice, originating from Svalbard, is able to form over Sentralbanken, providing that at least 60 m of uplift is achieved in the central Barents Sea. Grounded ice within Bjørnøyrenna was only predicted when the amplitude of the local forebulge exceeded 250 m.

Late Weichselian Glaciation of the Russian High Arctic

1999 ◽  
Vol 52 (3) ◽  
pp. 273-285 ◽  
Author(s):  
Martin J. Siegert ◽  
Julian A. Dowdeswell ◽  
Martin Melles
Keyword(s):  
Barents Sea ◽  
Ice Sheet ◽  
High Arctic ◽  
The North ◽  
The Barents Sea ◽  
Geological Information ◽  
Late Weichselian ◽  
Barents And Kara Seas ◽  
Severnaya Zemlya ◽  
Weichselian Glaciation

A numerical ice-sheet model was used to reconstruct the Late Weichselian glaciation of the Eurasian High Arctic, between Franz Josef Land and Severnaya Zemlya. An ice sheet was developed over the entire Eurasian High Arctic so that ice flow from the central Barents and Kara seas toward the northern Russian Arctic could be accounted for. An inverse approach to modeling was utilized, where ice-sheet results were forced to be compatible with geological information indicating ice-free conditions over the Taymyr Peninsula during the Late Weichselian. The model indicates complete glaciation of the Barents and Kara seas and predicts a “maximum-sized” ice sheet for the Late Weichselian Russian High Arctic. In this scenario, full-glacial conditions are characterized by a 1500-m-thick ice mass over the Barents Sea, from which ice flowed to the north and west within several bathymetric troughs as large ice streams. In contrast to this reconstruction, a “minimum” model of glaciation involves restricted glaciation in the Kara Sea, where the ice thickness is only 300 m in the south and which is free of ice in the north across Severnaya Zemlya. Our maximum reconstruction is compatible with geological information that indicates complete glaciation of the Barents Sea. However, geological data from Severnaya Zemlya suggest our minimum model is more relevant further east. This, in turn, implies a strong paleoclimatic gradient to colder and drier conditions eastward across the Eurasian Arctic during the Late Weichselian.

Late Weichselian ice-sheet flow directions in the Russian northern Barents Sea from high-resolution imagery of submarine glacial landforms

Geology ◽  
2021 ◽  
Author(s):  
Julian A. Dowdeswell ◽  
Aleksandr Montelli ◽  
Grigorii Akhmanov ◽  
Marina Solovyeva ◽  
Yana Terekhina ◽  
...  
Keyword(s):  
Barents Sea ◽  
Late Quaternary ◽  
Ice Flow ◽  
Novaya Zemlya ◽  
Franz Josef Land ◽  
High Resolution Imagery ◽  
Anna Trough ◽  
Flow Convergence ◽  
Late Weichselian ◽  
Glacial Landforms

The locations and orientations of more than 1000 late Quaternary subglacial and ice-marginal landforms, including streamlined sedimentary bed forms, glacitectonic hill-hole pairs, meltwater channels, and eskers, were mapped from blocks of multibeam data (area of 4861 km2) in the little-known Russian Barents Sea. Between Sentralbanken and Admiralty Bank, at ~75°N, there is evidence for southward ice flow. Ice-flow indicators between Franz Josef Land and Novaya Zemlya show northeast flow into the head of St. Anna Trough. There is also evidence of southeast flow off the bank to the south of Franz Josef Land, and of flow convergence with northeast-flowing ice in Sedov Trough. Northeast flow of ice between Novaya Zemlya and Franz Josef Land suggests that the latter archipelago was not overrun by ice flowing north from the Barents Sea and, therefore, that a subsidiary ice dome was likely on Franz Josef Land. A major ice divide was also present at ~76°N –77°N in the Russian Barents Sea.

Numerical Modeling of the Late Weichselian Svalbard-Barents Sea Ice Sheet

1995 ◽  
Vol 43 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Martin J. Siegert ◽  
Julian A. Dowdeswell
Keyword(s):  
Numerical Model ◽  
Sea Ice ◽  
Barents Sea ◽  
Ice Sheet ◽  
Ice Cover ◽  
Time Dependent ◽  
Southern Limit ◽  
Geological Evidence ◽  
Iceberg Calving ◽  
Late Weichselian

AbstractPrevious reconstructions of the ice cover of the Svalbard-Barents Sea region during the late Weichselian have ranged from small ice masses on Svalbard to complete inundation of the Barents Shelf region by an ice sheet several kilometers thick. We have used a time-dependent finite-difference numerical model to undertake a new glaciological reconstruction for the Svalbard-Barents Sea Ice Sheet over the last 30,000 yr. The numerical model requires environmental forcing functions in the form of air temperature and precipitation and their behavior with respect to altitude, together with sea-level change and an iceberg calving relation. Ice buildup on Svalbard is calculated to have begun 28,000 yr ago, and maximum dimensions were reached by 20,000 yr ago, covering Svalbard and the northwestern Barents Sea with a center of mass (1.3 km thick) around eastern Svalbard. Decay was complete by about 10,000 yr ago. The margin of the modeled ice sheet at its maximum is in good agreement with observed sea-floor morphological features, but there are discrepancies in timing between the modeled ice sheet decay and (i) a dated meltwater spike in Fram Strait and (ii) the observed rebound curves for Svalbard. An inverse approach was used to predict ice sheet decay, and it was found that increasing the rate of iceberg calving within the model produces a deglaciation some 2000 yr earlier, which is compatible with these two independent datasets. The reconstruction is also compatible with geological evidence on the isostatic response of Bjørnøya, close to the southern limit of the ice sheet, and seismically observed deposits, interpreted to be ice. proximal facies, located in the northwestern Barents Sea. Our time-dependent model reconstructions of the Svalbard-Barents Sea Ice Sheet indicate ice cover over only the northwestern Barents Sea during the late Weichselian, but this does not preclude the presence of ice derived from Fennoscandia and the Kara Sea region elsewhere in the Barents Sea.

scholarly journals Asymmetric ice-sheet retreat pattern around northern Scotland revealed by marine geophysical surveys

2014 ◽  
Vol 105 (4) ◽  
pp. 297-322 ◽  
Author(s):  
Tom Bradwell ◽  
Martyn Stoker
Keyword(s):  
Continental Shelf ◽  
Ice Sheet ◽  
Large Area ◽  
Ice Dynamics ◽  
Single Beam ◽  
Orkney Islands ◽  
Bed Topography ◽  
Geophysical Surveys ◽  
Geological Information ◽  
Late Weichselian

ABSTRACTThis study uses marine geophysical data, principally single-beam and high-resolution multibeam echo sounder bathymetry, combined with seismic sub-bottom profiles, and existing Quaternary geological information, to map the glacial geomorphology of a large area of seafloor (∼50,000 km2) on the continental shelf around northern Scotland, from west of Lewis to north of the Orkney Islands. Our new mapping reveals the detailed pattern of submarine glacial landforms, predominantly moraines, relating to ice sheets that covered Scotland and much of the continental shelf during the Late Weichselian glaciation and earlier in the Mid to Late Pleistocene. The reconstructed retreat pattern based on geomorphological evidence highlights the large number of different retreat stages and the asymmetric, non-uniform evolution of this ice sheet sector during Late Weichselian deglaciation. Time-equivalent ice-front reconstructions show that marine sectors of the ice sheet, such as the Minch, changed their geometry significantly, perhaps rapidly; whilst other sectors remained relatively unchanged and stable. We suggest that this behaviour, governed principally by bed topography/bathymetry and ice dynamics, led to reorganisation of the Late Weichselian ice sheet as it retreated back to two main ice centres: one in Western Scotland and the other over Orkney and Shetland. This retreat pattern suggests relatively early deglaciation of NW Lewis (ca. 25 ka BP) and the mountains of far NW Scotland – the latter possibly forming a substantial ice-free land corridor. Our reconstructions differ from most previous syntheses, but are strongly supported by the independently-mapped offshore Quaternary succession and key onshore dating constraints.

Co, Hf, Ce, Cr, Th, and REE systematics of modern bottom sediments of the Barents sea

2019 ◽  
Vol 485 (2) ◽  
pp. 207-211
Author(s):  
A. V. Maslov ◽  
N. V. Politova ◽  
V. P. Shevchenko ◽  
N. V. Kozina ◽  
A. N. Novigatsk ◽  
...  
Keyword(s):  
Bottom Sediments ◽  
Barents Sea ◽  
Western Coast ◽  
Novaya Zemlya ◽  
The North ◽  
The Barents Sea ◽  
Franz Josef Land ◽  
Pechora River ◽  
Marine Areas ◽  
Bottom Grab

The Co, Hf, Ce, Cr, Th, and REE systematics are analyzed for modern sediments collected by a bottom grab during the 67th and 68th cruises of R/V “Akademik Mstislav Keldysh” and samples taken in the Barents Sea bays and inlets. Our results indicate that most modern bottom sediments are composed of fine silicoclastic material enhanced with a suspended matter of the North Cape current, which erodes the western coast of Scandinavia, and due to bottom erosion of some marine areas, as well as erosion of rock complexes of the Kola Peninsula, Novaya Zemlya, and Franz Josef Land (local provenances). Material from Spitsbergen also probably played a certain role. In the southern part of the Barents Sea, clastic material is supplied by the Pechora River.

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