V.—Glacial Geology: Old and New

1892 ◽  
Vol 9 (7) ◽  
pp. 310-321
Author(s):  
T. Mellard

Over twenty years ago I commenced the study of the glacial deposits of the neighbourhood of Liverpool, and as the observations grew they came to embrace a considerable share of the drainagebasin of the Irish Sea.I have personally inspected and kept full records of all of the important artificial excavations likely to throw light upon the subject, in addition to examining and making sections of the natural exposures of glacial drift which abound on the north-west coast of England, the coast of Wales, and in the river valleys draining into the Irish Sea, and to a lesser extent the drift on the east-coast of Ireland and the south of Scotland.

Author(s):  
D. J. Crisp

Material collected prior to 1940 indicates that Elminius modestus was not present on British coasts at that time.Elminius increased in abundance in south-east England from 1946 to 1950 and extended its range as far as the Humber, where it halted.Its advance westwards along the south coast was similarly halted at Portland, but by 1948 independent colonies had been established in several of the river systems of Devon and Cornwall, in Milford Haven, and in the Bristol Channel.The first populations in the Irish Sea were in Morecambe Bay. From there Elminius spread rapidly south and west along the north coast of Wales, and more slowly north and west towards Galloway, eventually bridging the sea to the Isle of Man.Detailed observations showed that Elminius advanced along the uniformly favourable north coast of Wales as a definite front moving at a rate of approximately 20–30 km per year. Around Anglesey where tidal currents were stronger it appeared simultaneously in many scattered centres.A distinction is drawn between marginal dispersal taking place under the influence of normal agencies at the boundary of an existing population, and remote dispersal due to an artificial or freak transport over a long distance. In the case of Elminius the maximum distance that is likely to be bridged by marginal dispersal in the absence of strong residual drifts is about 30 miles.Elminius probably first appeared near Southampton, and was introduced into the Thames estuary area probably by remote dispersal. Thence it spread along the east coast and was transported to Holland. Its extension into south Devon, the Bristol Channel, the Irish Sea, and to the French coast must also be attributed to remote dispersal.The main ecological effects of Elminius result from competition for space with Balanus balanoides. Since Elminius breeds in summer, its dominance has a profound effect on the composition of the summer plankton, greatly increasing the number of barnacle nauplii, presumably at the expense of other larvae.


1904 ◽  
Vol 1 (10) ◽  
pp. 504-505
Author(s):  
Edward Greenly

The bare and rocky hill known as Holyhead Mountain is of considerable interest in connection with recent geological events, standing as it does some thirty miles out from the highlands of Carnarvonshire into the Irish Sea Basin; and in such remarkable isolation, for it is much the highest of the five hills which rise above the general level of the platform of Anglesey.Its height is only 721 feet, but so strongly featured is it, especially towards the west, that one feels the term ‘mountain’ to be no misnomer, and can hardly believe it to be really lower than many of our smooth wolds and downs of Oolite and Chalk. Being composed, moreover, of white quartzite (or more properly of quartzite-schist), and being so bare of vegetation, it recalls much more vividly certain types of scenery in the Scottish Highlands than anything in those Welsh mountains that one sees from its sides. Towards the east it slopes at a moderate angle, but a little west of the summit it is traversed by a very strong feature, due to a fault, running nearly north and south, along which is a line of great crags, facing west, and prolonged northwards into the still greater sea cliffs towards the North Stack. Beyond this the land still remains high, but is smoother in outline, a somewhat softer series of rocks extending from the fault to the South Stack, where the high moors end off in great cliffs above the sea.


1960 ◽  
Vol 67 (4) ◽  
pp. 351-362 ◽  
Author(s):  
A. D. McIntyre

SynopsisFrom a faunistic survey in Scottish waters, concentrated mainly in the sea lochs of the north-west coast and in the deep water in the North Sea off the east coast, thirty-two species of polychætes are listed which have not previously been recorded from these areas. Seven of the species are new records for British coastal waters or for the North Sea.


Author(s):  
J. B. Wilson ◽  
N. A. Holme ◽  
R. L. Barrett

A number of species of ophiuroid are known to occur in dense clusters on the sea-bed. Aggregations of Ophiothrix fragilis (Abildgaard) have been recorded from the English Channel by Allen (1899), Vevers (1951, 1952), Barnes (1955), Ancellin (1957), Cabioch (1961, 1967, 1968), Holme (1966), Warner (1969, 1971), and by Allain (1974). Beds of the same species have been found in the Irish Sea by Jones (1951) and by Brun (1969), on the west coast of Ireland by Könnecker & Keegan (1973) and Keegan (1974), and on the west coast of Scotland, where it is widespread in sea lochs and elsewhere around the coast (McIntyre, 1956, and personal communication, 1975). Records of Ophiothrix fragilis from the North Sea have been summarized by Ursin (1960). In the Mediterranean, aggregations of Ophiothrix quinquemaculata (D.Ch.) have been described by Guille (1964, 1965) from off the south coast of France, and by Czihak (1959) from the Adriatic. Hurley (1959) gives underwater photographs of Ophiocomina bollonsi Farquhar from the Cook Strait, New Zealand. Further examples of aggregation in ophiuroids and other echinoderms are cited by Reese (1966), Mileykovskiy (1967) and by Warner (1978).


1980 ◽  
Vol 100 ◽  
pp. 83-86
Author(s):  
A. B Armour-Brown ◽  
T Tukiainen ◽  
B Wallin

The SYDURAN project completed the airborne gamma-spectrometer and geochemical sampling survey over some 14 000 km2 of south-west Greenland from the fjord Sermiligarssuk in the north-west to Kap Farvel in the south and up the east coast as far as the southern shore of Lindenows Fjord. This covered all the Ketilidian structural zones and a small area of Archaean as classified by Allaart (1976) (fig. 29). Geological field work and prospecting of a more detailed nature was carried out in five areas where previous work indicated possibie uranium mineralisation.


Author(s):  
W.G. Sanderson ◽  
R.H.F. Holt ◽  
L. Kay ◽  
K. Ramsay ◽  
J. Perrins ◽  
...  

The spatial heterogeneity of epifauna on a Modiolus modiolus reef off north-west Wales was investigated using divers. The community associated with these horse mussels was similar to that described previously from Loch Creran and the north basin of Strangford Lough. Some differences in epifauna may be attributable to the less sheltered nature of the site. Modiolus modiolus numbers and the associated epifaunal community were significantly different between ridge and trough sub-habitats. Troughs can be considered ‘reduced’ ridge communities whereas ridges have high densities of horse mussels and certain sessile taxa were correlated with their abundance. Modiolus modiolus aggregation as a competitive response to the feeding environment, enhanced food availability on ridges and sediment deposition amongst mussel clumps may start to explain the undulating bed-form. Patchiness in community composition and periodic cover by ophuroids has implications when considering the monitoring of the horse mussel community. Stratified, in situ recording of the highly populated ridges could improve the statistical sensitivity of monitoring horse mussel reefs whilst simultaneously focusing on the more sensitive indicators of fishing threats.


1909 ◽  
Vol 6 (11) ◽  
pp. 507-508
Author(s):  
F. R. Cowper Reed

The occurrence of a pre-Glacial marine terrace and raised beach along the coast of the south of Ireland was described by Messrs. Wright & Muff in 1904, and its development in the eastern part of co. Waterford was the subject of two short papers by the author in 1907 in this Magazine. Messrs. Wright & Muff (op. cit.) observed the same raised beach only in the south-eastern portion of co. Wexford, so that its recognition this summer by the author further north along the east coast of Ireland deserves recording, for it has been traced for several miles to the north and south of Courtown Harbour, and its height, characters, and relations to the overlying deposits show that it is a continuation of the same feature. The first locality to be mentioned is about 3 miles to the south of the village of Courtown, where relics of it are preserved between Roney Point and Salt Rock; it is still more distinct as a rock-terrace a little further north at Pollshone Head and Breanoge Head, but in the bays between these points the conditions are not favourable for its exposure, as there are no rocky cliffs, only extensive sand-dunes stretching along the shore. From Courtown Harbour northwards for about 2 miles to Duffcarrig Rocks sand-dunes are similarly developed, forming a nearly continuous line of ridges rising to heights of over 50 feet. Thick drift deposits occur behind them, but no pre-Glacial cliff or platform is exposed. At Duffcarrig Rocks solid rock again appears forming the headland, and we can recognize remnants of the rock-cut shelf in a much eroded and fissured condition.


1914 ◽  
Vol 1 (5) ◽  
pp. 211-215 ◽  
Author(s):  
C. A. Matley

The subject of the derivation of the materials which form the Bunter Pebble-beds has given rise to wide differences of opinion and to a voluminous literature. These it is not my intention to recapitulate, as an excellent summary of the subject will be found in Mr. O. H. Shrubsole's paper of 1903. Mr. Shrubsole then gathered together the known evidence, added some new facts of his own, and came to the conclusion that the Midland Bunter pebbles were brought from a southerly direction. This opinion may be said to have held the field until recently, when the question was again taken up by Mr. Jukes-Browne in the third edition of The Building of the British Isles (1911). After reviewing the whole evidence and taking into consideration the results of an investigation by Mr. E. C. Martin, which tended to show that the direction of transportation in Somersetshire in Bunter times was towards the south, Mr. Jukes-Browne abandoned the view he had taken in the second edition (1892) of that work, and now, adopting in the main the conclusions of Professor Bonney, considers that the bulk of the pebbles of the Midland Bunter came from the north-west, though he agrees that the fossiliferous quartzite pebbles could not have come from that direction, and he suggests for these a south-easterly derivation (Suffolk).


1890 ◽  
Vol 16 ◽  
pp. 39-64
Author(s):  
His Grace the Duke of Argyll

The magnificent sections of the Archæan and Palæozoic rocks which are presented on the north-west coast of Scotland, have long been known to all British geologists. They occur principally in the counties of Sutherland and Wester Ross, from Cape Wrath on the north to Loch Kishorn on the south. They are not less striking in an artistic, than they are instructive in a scientific point of view. The height of the mountains, their abrupt and precipitous forms, and the thinness, or almost total absence of, superficial covering, are characteristics which combine with great variety and richness of colouring, to produce scenery which stands altogether by itself


2021 ◽  
Vol 8 ◽  
Author(s):  
Jonathan Tinker ◽  
Leon Hermanson

We investigate the winter predictability of the North West European shelf seas (NWS), using the Met Office seasonal forecasting system GloSea5 and the Copernicus NWS reanalysis. We assess GloSea5’s representation of NWS climatological winter and its skill at forecasting winter conditions on the NWS. We quantify NWS winter persistence and compare this to the forecast skill. GloSea5 simulates the winter climatology adequately. We find important errors in the residual circulation (particularly in the Irish Sea) that introduce temperature and salinity biases in the Irish Sea, English Channel, and southern North Sea. The GloSea5 winter skill is significant for SST across most of the NWS but is lower in the southern North Sea. Salinity skill is not significant in the regions affected by the circulation errors. There is considerable NWS winter temperature and salinity persistence. GloSea5 exhibits significant predictive skill above this over ∼20% of the NWS, but for most of the NWS this is not the case. Dynamical downscaling is one method to improve the GloSea5 simulation of the NWS and its circulation, which may reduce biases and increase predictive skill. We investigate this approach with a pair of case studies, comparing the winters of 2010/2011 and 2011/2012 (with contrasting temperature and salinity anomalies, and NAO state). While 2 years are insufficient to assess skill, the differences in the simulations are evaluated, and their implications for the NWS winter predictability are considered. The NWS circulation is improved (where it was poor in the GloSea5), allowing more realistic advective pathways for salinity (and temperature) and enhancing their climatological spatial distributions. However, as the GloSea5 SST anomaly is already well simulated, downscaling does not substantially improve this – in other seasons or for other variables, downscaling may add more value. We show that persistence of early winter values provides some predictive skill for the NWS winter SST, and that the GloSea5 system adds modestly to this skill in certain regions. Such information will allow prospective end-users to consider how seasonal forecasts might be useful for their sector, providing the foundation on which marine environmental seasonal forecasts service and community may be developed for the NWS.


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