The Last Glaciation and Geomorphology

2005 ◽  
Author(s):  
Margot Böse
Keyword(s):  
Boreal Forests ◽  
Ice Sheet ◽  
Drainage System ◽  
Middle Part ◽  
Middle Pleistocene ◽  
Last Interglacial ◽  
The North ◽  
Last Glaciation ◽  
The North Sea ◽  
Late Weichselian

The Weichselian ice sheets were smaller than those of the preceding Middle Pleistocene and covered only the north-eastern part of the German lowland, as well as the eastern and northern parts of the Jutland peninsula. The Late Weichselian (Late Devensian) ice sheet also covered the northern part of the North Sea Basin (Ehlers and Wingfield 1991). The young morainic landscape still has distinct morphological features distinguishing it from the old morainic areas with relief shaped by the long-lasting periglacial processes during the Weichselian. The area of the last glaciation is easily recognizable on topographical maps owing to the irregular relief and the numerous lakes that are still preserved today. This scenic landscape also features end moraines and kames, till plains, and huge meltwater valleys (pradolinas or Urstromtäler), as well as a complex drainage system. The general climatic development of the last interglacial- glacial-Holocene cycle can be interpreted from curves showing the ratio of the oxygen isotopes 18O and 16O in deep-sea sediments, which is indirectly indicative of the growth of ice masses worldwide. The different OIS (Oxygen Isotope Stages) are numbered, with uneven numbers representing the relatively warmer phases. OIS 5e corresponds to the Eemian Interglacial. The stages 5d–5a represent the Early Weichselian, which is colder than the preceding interglacial but is subdivided into stadials and interstadials. The Brørup interstadial s.l., including both the Amersfoort (5c) and the Odderade interstadial (5a), is characterized by boreal forests in this part of Europe. OIS 4 marks the onset of the Middle Weichselian or Pleniglacial, and is the first stage involving much lower temperatures and the growth of considerable ice masses. This is probably the time when a real inland ice sheet started to grow in Fennoscandia. OIS 3, the middle part of the Pleniglacial, is represented by several climatic changes. The interstadials—or intervals, as they are also called—such as Oerel, Glinde, Moershoofd, Hengelo, and Denekamp—are well documented by terrestrial palynological records of a herb and shrub bush vegetation (van der Hammen et al. 1967; Behre 1989; Caspers and Freund 2001).

The Impact of Global Ice Sheet Evolution on North Sea Glacial Isostatic Adjustment during the Last Interglacial

2021 ◽  
Author(s):  
Oliver Pollard ◽  
Natasha Barlow ◽  
Lauren Gregoire ◽  
Natalya Gomez ◽  
Víctor Cartelle
Keyword(s):  
Sea Level ◽  
North Sea ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Glacial Maximum ◽  
Last Interglacial ◽  
Isostatic Adjustment ◽  
The North ◽  
The North Sea ◽  
The Impact

<p>The Last Interglacial (LIG) period (130 - 115 ka) was the last time in Earth’s history that the Greenland and Antarctic ice sheets were smaller than those of today due, in part, to polar temperatures reaching 3 - 5 °C above pre-industrial values. Similar polar temperature increases are predicted in the coming decades and the LIG period could therefore help to shed light on ice sheet and sea level mechanisms in a warming world.</p><p>The North Sea region is a promising study site for the reconstruction of both the magnitude and rate of LIG sea-level change as well as the identification of relative, individual ice sheet contributions to sea level. The impact of glacial isostatic adjustment (GIA) is particularly significant for the North Sea region due to its proximity to the former Eurasian ice sheet, which deglaciated during the penultimate deglaciation leading into the LIG. The evolution of the local Eurasian and global ice sheets during the penultimate glacial cycle has left a complex spatio-temporal pattern of GIA during the LIG, both regionally and globally. In addition, interpretation of the LIG record is further complicated by uncertainties in ongoing earth deformation and sea level evolution since the LIG. However, there are large uncertainties in the geometry and evolution of global ice sheets before the Last Glacial Maximum and, in particular, a major source of uncertainty for North Sea LIG records is the geometry and evolution of the Eurasian ice sheet during the Penultimate Glacial Maximum (PGM).</p><p>We produce a range of plausible global ice sheet histories spanning the last 400 thousand years that vary in penultimate deglaciation characteristics including glacial maximum ice sheet volume, deglaciation timing, and the ice volume distribution of the Eurasian ice sheet. This novel PGM Eurasian component is constructed with the use of a simple ice sheet model (Gowan et al. 2016) enabling systematic variation in the thickness of each ice sheet region within known uncertainty ranges. We then employ a gravitationally consistent sea level model (Kendall et al. 2005) with a range of viscoelastic Earth structure models to calculate the global GIA response to each ice history and to infer which input parameters the North Sea LIG signal is most sensitive to. This work will improve our understanding of the GIA effects on near field relative sea level during previous interglacials and will enable a systematic quantification of uncertainties in LIG sea level in the North Sea.</p>

Geochronology and palaeoenvironment of marine Quaternary deposits in Denmark: new evidence from northern Jutland

1999 ◽  
Vol 136 (5) ◽  
pp. 561-578 ◽  
Author(s):  
H. P. SEJRUP ◽  
K. L. KNUDSEN
Keyword(s):  
North Sea ◽  
Atlantic Water ◽  
Marine Isotope Stage ◽  
Last Interglacial ◽  
The Holocene ◽  
The North ◽  
Hole Area ◽  
Northwest Europe ◽  
The North Sea ◽  
Late Weichselian

The degree of isoleucine epimerization in the benthic foraminiferal species Elphidium excavatum and Bulimina marginata have been measured in four boreholes, penetrating marine interglacial beds, from northern Jutland. The results of these analyses are compiled with results obtained from other sites in Denmark and the North Sea region, and four aminozones (AZs) have been erected. AZ1 (aIle/Ile < 0.05) include the Late Weichselian and the Holocene part of the record. AZ2 (0.08–0.12) includes samples of last interglacial age. AZ3 (0.14–0.16) includes samples from sites that have been previously correlated with the Holsteinian, and marine isotope stage 7 age for this zone is suggested. An age close to 400±100 ka is assigned to AZ4 (0.21–0.26). AZ4 is recorded in corings at Skagen and Nørre Lyngby, and includes the here defined Skagerrak Interglacial, which is tentatively correlated with marine isotope stage 11.The Skagerrak Interglacial sediments are characterized by boreal lusitanian benthic foraminiferal faunas evidencing strong input of Atlantic water to the North Sea. These faunas are replaced by assemblages indicating cooler conditions at least twice during this period. The sedimentation pattern in northern Jutland during this interglacial seems to be different from the sedimentation regimes in the same area at the classical Eemian sites and during the Holocene, which were characterized by large sediment input from the Jutland Current. This difference may be attributed to a change in the geometry of the sedimentary basin through the later part of the Quaternary, which is a result of repeated periods of intense erosion in the confluence area of the Norwegian Channel ice stream. A strong influx of Atlantic water to the North Sea during stage 11 has been suggested earlier, based on records from the Devil's Hole area. However, the correlation of this event to the classic biostratigraphic based schemes of northwest Europe is still problematic.

scholarly journals North Sea palaeogeographical reconstructions for the last 1 Ma

2014 ◽  
Vol 93 (1-2) ◽  
pp. 7-29 ◽  
Author(s):  
K.M. Cohen ◽  
P.L. Gibbard ◽  
H.J.T. Weerts
Keyword(s):  
North Sea ◽  
Large Scale ◽  
Middle Pleistocene ◽  
Glacial Cycle ◽  
Last Interglacial ◽  
Sedimentary Environments ◽  
The North ◽  
Basin Scale ◽  
The North Sea ◽  
Cyclic Changes

AbstractThe landscape evolution of the southern North Sea basin is complex and has left a geographically varying record of marine, lacustrine, fluvial and glacial sedimentation and erosion. Quaternary climatic history, which importantly included glaciation, combined with tectonics gave rise to cyclic and non-cyclic changes of sedimentation and erosion patterns. Large-scale landscape reorganisations left strong imprints in the preserved record, and are important for the detail that palaeogeographical reconstructions for the North Sea area can achieve. In the spirit of the North Sea Prehistory Research and Management Framework (NSPRMF; Peeters et al., 2009), this paper provides background geological information regarding the North Sea. It summarises current stratigraphical and chronological frameworks and provides an overview of sedimentary environments. As we go back in time, the understanding of Quaternary palaeo-environmental evolution in the North Sea basin during the last 1 million years becomes decreasingly accurate, with degree of preservation and accuracy of age control equally important controls. Comparing palaeogeographical reconstructions for the Middle Pleistocene, the last interglacial-glacial cycle and the period following the Last Glacial Maximum illustrates this. More importantly, a series of palaeogeographical maps provide an account of basin-scale landscape change, which provides an overall framework for comparing landscape situations through time.

scholarly journals The North Sea Ice Sheet

Nature ◽  
1894 ◽  
Vol 50 (1282) ◽  
pp. 79-79
Author(s):  
HENRY H. HOWORTH
Keyword(s):  
Sea Ice ◽  
North Sea ◽  
Ice Sheet ◽  
The North ◽  
The North Sea

V.—Mr. Harkee and Mr. Debley on the Scandinavian Ice-Sheet

1894 ◽  
Vol 1 (11) ◽  
pp. 496-499
Author(s):  
Henry H. Howorth
Keyword(s):  
Ice Sheet ◽  
Good Effect ◽  
The North ◽  
The Matrix ◽  
Glacier Ice ◽  
Inductive Methods ◽  
The North Sea ◽  
Antarctic Continent ◽  
The Alps ◽  
The Difference

Mr. Deeley tells your readers that he has recently been to the summit of Mont Blanc, and has been studying the difference between névé and glacier ice. This is interesting; but we thought that a great many people had done the same thing during the last hundred years, and we thought that one of them, Forbes, had studied the famous Mountain and the phenomenoninquestion to good effect, not in a casual visit to the Alps, but in the course of many years of patient labour. Among other things we also thought he had shown that in a viscous body like ice, the slope of the upper surface necessary to make it begin to move is the same as the slope which, would be required to induce motion in the ice if its bed were inclined at an angle. He further collected considerable evidence to show what the least angle is upon which ice will begin to move. This is the slope, the least slope, available. It is nothing less than astounding to me that anyone should venture to postulate a Scand in avian ice-sheet in the North Sea until he had considered this necessary factor, and how it would operate.The Scand in avian ice-sheet was, I believe, the invention of Croll, who, sittinginhis arm-chair and endowed with a brilliant imagination, imposed upon sober science this extraordinary postulate. He did not dream of testing it by an examination of the coasts of Norway, or even of Britain, but put it forward apparently as a magnificent deduction. All deductions untested by experiment are dangerous. Thus it came about that the great monster which is said to have come from Norway, goodness knows by what mechanical process, speedily dissolved away on the application of inductive methods. Of course it still maintained its hold upon that section, of geologists who dogmatiseinprint a great deal about the Glacial period before they have ever seen a glacier at work at all; but I am speaking of those who have studied the problem inductively. First Mr. James Geikie, a disciple of Croll, was obliged to confess that this ice-sheet, which is actually said to have advanced as far as the hundred-fathom line in the Atlantic, and there presented a cliff of ice like the Antarctic continent, never can have reached the Faroes, which had an ice-sheet of their own. Next Messrs. Peach and Home were constrained to admit that no traces of it of any kind occur in the Orkneys, or in Eastern Scotland. They still maintained its presence in the Shetlands; however, this was upon evidence which is somewhat extraordinary. I do not mean the evidence as to the direction of the striation, which was so roughly handled by Mr. Milne-Home, but I mean the evidence they adduce that the boulders found on the islands are apparently all local ones, and that, contrary to the deposits of glaciers, they diminish in number as we recede from the matrix whence they were derived.

VII.—Glacier Lake Channels

1916 ◽  
Vol 3 (1) ◽  
pp. 26-29
Author(s):  
Percy Fry Kendall
Keyword(s):  
North Sea ◽  
Ice Sheet ◽  
Glacial Deposits ◽  
Marine Origin ◽  
The North ◽  
The North Sea

In 1902 I published a paper, the outcome of several years' observation, on certain phenomena associated with the glacial deposits of the Cleveland area, which I attributed to the former presence of a series of temporary lakes and lakelets upheld in the recesses of the hills by the margin of a great ice-sheet occupying the greater part of the North Sea. This interpretation met with so wide an acceptance, even by those geologists familiar with the district who had previously attributed the glacial deposits to a marine origin, that during the succeeding thirteen years I have steadfastly refrained from replying to criticism, hoping by this abstention to keep the issues unclouded by a controversy that might at any stage develop an acerbity not always lacking in earlier discussions.

New results on the dynamics of the NW part of the Svalbard Ice Sheet during the deglaciation of the Woodfjorden Trough

2020 ◽  
Author(s):  
Tom Arne Rydningen ◽  
Amando Lasabuda ◽  
Jan Sverre Laberg ◽  
Christine Tømmervik Kollsgård ◽  
Stine Bjordal Olsen ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Ice Sheet ◽  
Outer Part ◽  
Middle Part ◽  
The Arctic ◽  
Quality Data ◽  
Glacier Front ◽  
Ice Retreat ◽  
Late Weichselian ◽  
Glacial Landforms

&lt;p&gt;Present-day warming is most pronounced at high latitudes, raising concern for the stability of modern ice caps such as the ones overlying the Svalbard archipelago. Palaeo-records give us opportunity to understand past behavior of these systems, including the ice retreat from the continental shelf at the end of the last glaciation. In order to evaluate and reconstruct this in a robust way, it is essential that we acquire high-quality data sets covering key areas in the Arctic.&lt;/p&gt;&lt;p&gt;New multi-beam bathymetric data was acquired in July 2019 from the Woodfjorden Trough; an up to 60 km long and 40 km wide transverse trough on the northwestern part of the Svalbard continental shelf. Previous investigations have shown that this trough was occupied by a major ice stream draining the Svalbard Ice Sheet during the last glacial, but the deglacial dynamics of this sector of the Svalbard Ice Sheet are presently not well constrained.&lt;/p&gt;&lt;p&gt;The new data reveal a complex seabed morphology including larger (2 km wide, 50 m high) and smaller (100 m wide, 3 m high) ridges, as well as sediment wedges (1 to 2 km wide, 30 m high), partly showing crosscutting relationships. These ridges and wedges are discontinuous in the outer part of the trough, where they are partly superposed by glacial lineations and small- to larger sized iceberg ploughmarks (up to 1500 m wide and 30 m deep). In the middle part of the trough, more continuous ridges dominate.&lt;/p&gt;&lt;p&gt;The ridges and wedges are interpreted to be glacial landforms formed by grounded ice within the Woodfjorden Trough. Their crosscutting relationships testify to a complex deglaciation, including several advances and still stands of the ice front during overall ice retreat, and their size could indicate that the glacier front was stable for some time. Smaller ridges may be retreat moraines formed during shorter (annual?) still stands of the glacier front. Based on their discontinuous characteristics, the ridges and wedges in the outer part of the trough may pre-date the final Late Weichselian deglaciation, i.e. they may have been overridden by a grounded glacier. The more continuous character of the ridges in the middle part of the trough indicate that these likely date from the Late Weichselian deglaciation.&lt;/p&gt;&lt;p&gt;The glacial landforms identified here are rather atypical for glacial troughs, commonly dominated by mega-scale glacial lineations superposed by one or a few grounding zone wedges and/or smaller retreat moraines. The abundant morainal systems and glacial lineations of the Woodfjorden Trough, instead, testify to highly dynamic grounded ice occupying the trough, and a retreat which was characterized by several periods of ice margin stability, interrupted by readvances. This fits with recent studies from onshore areas, showing that the deglaciation of northern Svalbard was at least partly characterized by glacial readvances during the overall ice retreat.&lt;/p&gt;

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.

scholarly journals Quaternary palaeoceanography and palaeogeography in northern Denmark: a review of results from the Skagen cores

1996 ◽  
Vol 43 ◽  
pp. 22-31
Author(s):  
Karen Luise Knudsen ◽  
Keld Conradsen ◽  
, Susanne Heier Nielsen ◽  
Marit-Solveig Seidenkrantz
Keyword(s):  
North Atlantic ◽  
Late Quaternary ◽  
Climatic Changes ◽  
Last Interglacial ◽  
North Atlantic Region ◽  
Atlantic Region ◽  
Radiocarbon Dates ◽  
Marine Deposits ◽  
The North ◽  
Late Weichselian

Palaeoenvironmental reconstructions from the Skagen record contribute to the understanding of Late Quatemary climatic changes and variations in the oceanographic circulation pattem in the entire North Atlantic region. The Skagen cores penetrated c. 192 m of Quatemary sediments comprising two marine Late Quaternary records: A 7 m marine unit (185.3-178.3 m) comprised the entire last interglacial, including its lower and upper transitions (Late Saalian-Eemian-Early Weichselian), while the upper 132 m of marine deposits covered the last about 15,000 years from the Late Weichselian through the Holocene, including the Pleistocene-Holocene transition. Results from the study of lithology, foraminifera, stable isotope measurements and radiocarbon dates are reviewed while emphasizing the most important contributions to the general understanding of the North Atlantic Quatemary history

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