scholarly journals The Last Scottish Ice Sheet

2018 ◽  
Vol 110 (1-2) ◽  
pp. 93-131 ◽  
Author(s):  
Colin K. BALLANTYNE ◽  
David SMALL
Keyword(s):  
North Sea ◽  
Ice Sheet ◽  
Irish Sea ◽  
Ice Streams ◽  
East Anglia ◽  
Ice Cap ◽  
The North ◽  
Outer Hebrides ◽  
Moray Firth ◽  
The North Sea

ABSTRACTThe last Scottish Ice Sheet (SIS) expanded from a pre-existing ice cap after ∼35 ka. Highland ice dominated, with subsequent build-up of a Southern Uplands ice mass. The Outer Hebrides, Skye, Mull, the Cairngorms and Shetland supported persistent independent ice centres. Expansion was accompanied by ice-divide migration and switching flow directions. Ice nourished in Scotland reached the Atlantic Shelf break in some sectors but only mid-shelf in others, was confluent with the Fennoscandian Ice Sheet (FIS) in the North Sea Basin, extended into northern England, and fed the Irish Sea Ice Stream and a lobe that reached East Anglia. The timing of maximum extent was diachronous, from ∼30–27 ka on the Atlantic Shelf to ∼22–21 ka in Yorkshire. The SIS buried all mountains, but experienced periods of thickening alternating with drawdown driven by ice streams such as the Minch, the Hebrides and the Moray Firth Ice Streams. Submarine moraine banks indicate oscillating retreat and progressive decoupling of Highland ice from Orkney–Shetland ice. The pattern and timing of separation of the SIS and FIS in the North Sea Basin remain uncertain. Available evidence suggests that by ∼17 ka, much of the Sea of the Hebrides, the Outer Hebrides, Caithness and the coasts of E Scotland were deglaciated. By ∼16 ka, the Solway lowlands, Orkney and Shetland were deglaciated, the SIS and Irish Ice Sheet had separated, the ice margin lay along the western seaboard, nunataks had emerged in Wester Ross, the ice margin lay N of the Cairngorms and the sea had invaded the Tay and Forth estuaries. By ∼15 ka, most of the Southern Uplands, the Firth of Clyde, the Midland Valley and the upper Spey valley were deglaciated, and in NW Scotland ice was retreating from fjords and valleys. By the onset of rapid warming at ∼14.7 ka, much of the remnant SIS was confined within the limits of Younger Dryas glaciation. The SIS, therefore, lost most of its mass during the Dimlington Stade. It is uncertain whether fragments of the SIS persisted on high ground throughout the Lateglacial Interstade.

VI.—On a Scandinavian Erratic from the Orkneys

1919 ◽  
Vol 6 (6) ◽  
pp. 273-274 ◽  
Author(s):  
W. I. Saxton ◽  
A. T. Hopwood
Keyword(s):  
North Sea ◽  
Ice Sheet ◽  
Glacial Period ◽  
General Behaviour ◽  
The North ◽  
Scandinavian Ice Sheet ◽  
Moray Firth ◽  
Westerly Direction ◽  
The North Sea

The general behaviour of the Scandinavian ice-sheet which spread over the North Sea at the climax of the Glacial period is fairly well known. Numerous erratics show that it reached the coast of Yorkshire and the eastern counties of England. Farther north no erratics have been found, but Dr. Jamieson and others have shown that it approached the coast of Aberdeen. Dr. Croll and Drs. Peach and Horne have shown that it forced the Scotch ice flowing eastward from the Moray Firth to turn in a northerly and north-westerly direction across the northern part of Caithness and over the Orkneys. They concluded that ice from the Christiania district must have passed a few miles to the north of the Orkneys. This is well shown in the chart attached to their paper and also in Professor James Geikie's map. The occurrence of a few Scandinavian erratics in the Orkneys would confirm these deductions. The only erratic recorded from Orkney which may be of Scandinavian origin is the Saville boulder described by Professor Heddle, Drs. Peach and Horne, and Dr. J. S. Flett.

The distribution, variation and origins of pre-Devensian tills in eastern England

1979 ◽  
Vol 287 (1024) ◽  
pp. 535-570 ◽  
Keyword(s):  
Calcium Carbonate ◽  
North Sea ◽  
Heavy Minerals ◽  
Ice Streams ◽  
Mineral Contents ◽  
East Anglia ◽  
The North ◽  
East Midlands ◽  
The North Sea ◽  
General Movement

In order to define quantitatively the lithological properties of the pre-Devensian tills in eastern England, calcium carbonate contents and mechanical compositions of 501 samples from 289 sites have been measured and heavy minerals counted in 102 of them. The results show that the tills may be divided into two groups: ( a ) a North Sea Drift group consisting of the Norwich Brickearth, the Cromer Tills, the Marly Drift of Cromer type and till members of the Contorted Drift, which is characterized by high sand and low opaque heavy mineral contents; and ( b ) a Lowestoft Till group including the Lowestoft Till of East Anglia, the Chalky Boulder Clay of the east Midlands, the Calcethorpe and Wragby Tills and the Lowestoft-type Marly Drift, which is characterized by low sand and high opaque values. The qualitative similarity of the mineral suites in the two groups, however, suggests a common origin in the North Sea basin. Automated contouring (SYMAP) has been used to represent the spatial distribution of till properties. These confirm that the Lowestoft Till group can be spatially separated from the North Sea Drift group, and divided into a Calcethorpe-Marly facies high in carbonates and lying astride the Wash, and a Lowestoft-Wragby facies with moderate but variable contents of calcium carbonate and occupying the rest of the region. Trend surface analysis has been applied to the Lowestoft Till group. At the first order level there are decreasing trends across the region, from northeast to southwest, in calcium carbonate, amphibole and epidote values and increasing trends in silt and clay. These are interpreted as showing a general movement from the North Sea of sandy and chalky material which became progressively modified by assimilation of Mesozoic clays. Higher order surfaces, particularly those of sand, garnet and amphibole values, point to the Wash as the focus of this glacial activity. It is proposed that the most vigorous stream of ice entered eastern England at this point, levelling the Cretaceous scarps and excavating the Jurassic clays of the Wash-Fens basin, and then fanned out into most of the region to deposit the clay-rich Lowestoft-Wragby facies. The Calcethorpe-Marly facies is considered to represent chalky North Sea material carried by marginal, and weaker, ice streams directly onto the Chalk of Lincolnshire and north Norfolk. The North Sea Drift group is believed to be the product of another ice body, penecontemporaneous with that depositing the Lowestoft group, which entered Norfolk from a more easterly part of the North Sea, incorporating sediments from this basin, but without crossing substantial outcrops of Jurassic or Lower Cretaceous formations or Tertiary clays. The Marly Drift includes a variant showing lithological affinities with both Lowestoft and Cromer Tills and which may be the product of complex interaction between the two ice sheets. All the tills studied seem most likely to be of Anglian age.

Implements from the Glacial Deposits of North Norfolk

1920 ◽  
Vol 3 (2) ◽  
pp. 200-205
Author(s):  
J. Cox
Keyword(s):  
Sea Ice ◽  
North Sea ◽  
Ice Sheet ◽  
East Anglia ◽  
Terminal Moraine ◽  
Glacial Origin ◽  
Long Period ◽  
The North ◽  
The North Sea ◽  
Boulder Clay

I discovered my first flint implement, a very fine Neolithic axe, in Gresham, in the year 1883, and this find led me to investigate the neighbourhood for other specimens. I was successful in finding many Neolithic implements of various kinds, which have from time to time been exhibited at the meetings of the Prehistoric Society of East Anglia.Shortly after my first finds, I commenced searching the gravels in the parish for “river drift” implements, but with very little success, as I soon found out that the gravel was of glacial origin, and the sandy surface of most of the district around was also glacial.The high ground to the north of Gresham consists of what is now fairly well known as the “Cromer-Holt ridge,” and is considered by Mr. F. W. Harmer, F.G.S., to be the terminal moraine of the North Sea ice sheet, built up while the glacier remained stationary for a long period, on its northward retreat. The numerous small valleys were formed by waters from the melting ice while the glacier was in its stationary stage, and may also have been influenced by the later glacier which deposited the chalky boulder clay.

The medieval cultures of the Irish sea and the North Sea: Manannan and his neighbors [Book Review]

2019 ◽  
Vol 15 ◽  
pp. 142-144
Author(s):  
John Kennedy
Keyword(s):  
North Sea ◽  
Irish Sea ◽  
The North ◽  
The North Sea ◽  
The Irish Sea

Review(s) of: The medieval cultures of the Irish sea and the North Sea: Manannan and his neighbors, by MacQuarrie, Charles W., and Nagy, Joseph Falaky Nagy (eds), (Amsterdam: Amsterdam University Press, 2019) hardcover, 212 pages, 1 map, 4 figures, RRP euro99; ISBN 9789462989399.

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

scholarly journals Ovary resorption in the Norway lobster (Nephrops norvegicus) and its possible causes with special reference to sperm storage

2020 ◽  
Vol 74 (1) ◽  
Author(s):  
Carola Becker ◽  
Jaimie T. A. Dick ◽  
E. Mánus Cunningham ◽  
Mathieu Lundy ◽  
Ewen Bell ◽  
...  
Keyword(s):  
North Sea ◽  
Demographic Data ◽  
Irish Sea ◽  
Natural Phenomenon ◽  
Nephrops Norvegicus ◽  
North East ◽  
The North ◽  
Norway Lobster ◽  
The North Sea ◽  
Reproductive Cycles

Abstract The Norway lobster, Nephrops norvegicus, is an important fisheries species in the North-East Atlantic area. In some circumstances, mature females of Nephrops norvegicus can resorb their ovary rather than completing spawning, but the implications of this phenomenon to reproductive biology and fisheries sustainability are not known. To understand after effects of ovary resorption, we studied long-term demographic data sets (1994–2017) collected from the western Irish Sea and the North Sea. Our considerations focused on potential correlations among the frequency of resorption, female insemination, and body size of resorbing females. Resorption was continuously rare in the western Irish Sea (less than 1%); whereas much higher rates with considerable year-to-year variation were observed in the North Sea (mean 9%). Resorption started in autumn after the spawning season (summer) had passed. The frequency stayed high throughout winter and declined again in spring. As sperm limitation can occur in male-biased fisheries, we expected a lack of insemination could be responsible for resorption, but affected females were indeed inseminated. Resorbing females were significantly larger than other sexually mature females in the North Sea, but the opposite trend was observed in the western Irish Sea. It is therefore possible that other, environmental factors or seasonal shifts, may trigger females to resorb their ovaries instead of spawning. Resorption may as well represent a natural phenomenon allowing flexibility in the periodicity of growth and reproduction. In this sense, observations of annual versus biennial reproductive cycles in different regions may be closely linked to the phenomenon of ovary resorption.

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.

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