The geology of the western approaches of the English Channel. I. Chalky rocks from the upper reaches of the continental slope

1962 ◽  
Vol 245 (724) ◽  
pp. 267-290 ◽  
Keyword(s):  
Continental Shelf ◽  
Continental Slope ◽  
Western Europe ◽  
Middle Eocene ◽  
English Channel ◽  
Geological Time ◽  
Structural Explanation ◽  
Upper Miocene ◽  
Clastic Sediment

Dredged samples of Tertiary chalks are described from five stations distributed over a distance of about 200 miles along the continental slope. The Foraminifera and nannoplankton indicate a range in age from Middle Eocene to Upper Miocene. The conclusions are reached that (i), the continental slope appears not to have received and retained much clastic sediment of recent geological time, (ii), the facies of the chalks is quite different from that recorded in western Europe, (iii), the chalks crop out at least in the upper reaches of the slope and form terraces, (iv), a structural explanation, probably faulting, is required to account for the conflicting topographical and stratigraphical levels of some samples and (v), there is no support for the existence before Pleistocene times of the continental shelf of the Western Approaches in physiographical form similar to that known today.

scholarly journals Cascading Over the Continental Slope of Water from the Celtic Sea

1949 ◽  
Vol 28 (3) ◽  
pp. 719-750 ◽  
Author(s):  
L. H. N. Cooper ◽  
David Vaux
Keyword(s):  
Continental Shelf ◽  
Continental Slope ◽  
English Channel ◽  
The South ◽  
Celtic Sea

In the Celtic Sea, to the south of Ireland, water in some winters becomes sufficiently cooled and heavy to flow to the edge of the continental shelf and to run down the continental slope to a depth of several hundred metres. A theory of the phenomenon, termed ‘cascading’, has been developed. Three winters have been examined in detail.In February 1927 much water, heavy enough to cascade, was present in the Celtic Sea and also in the English Channel. A probable course and speed of the cascading water over the shelf has been established. Since there were few observations of salinity and temperature over or beyond the slope, and none of oxygen anywhere, the theory cannot be completely established on the basis of the 1927 observations, full though they were.

Geology of the Western Approaches of the English Channel: a progress report

1962 ◽  
Vol 265 (1322) ◽  
pp. 395-406 ◽  
Keyword(s):  
Continental Shelf ◽  
Continental Slope ◽  
Progress Report ◽  
English Channel ◽  
Rock Outcrops ◽  
Logical Approach ◽  
Sea Bed ◽  
Westerly Direction ◽  
Sand And Gravel

Eight short cruises over the last 3 years, each of from 1 to 3 weeks’ duration in either R.V. Sarsia or R.R.S. Discovery II , were specially planned having regard to some of the geological and allied problems which could be expected in the Western Approaches leading out to the edge of the continental shelf, and hence to the upper parts of the continental slope. Fourteen scientists have so far participated in one or more of these cruises, mainly geologists and engineers. The primary geological objective is to try and arrive at an explanation of the origin of the continental slope, which will necessarily involve the origin of the adjacent continental shelf. To a geologist, the logical approach to the problems is, first, to determine the geological sequences in the shelf and, secondly, thus to extend the shallow structures and successions determined there to the upper reaches of the slope. The thin cover of a few inches of sand and gravel which normally occurs on the sea bed of the English Channel will almost certainly become too thick in a westerly direction for penetration by those coring methods which are at present available, and the most promising methods by means of which the established geology of the Western Approaches will be connected with the upper ranges of the continental slope are, first, the thumper and sparker techniques and, secondly, dredging from rock outcrops now known to occur on the slope. Such an orthodox geological approach demands progress pari passu from east to west. Our provisional results, of which progress reports follow, are thus mainly, but not entirely, concerned with the Western Approaches west of longitude 4° W.

Marine geology of the atlantic continental margin of europe

1969 ◽  
Vol 264 (1148) ◽  
pp. 31-75 ◽  
Keyword(s):  
Continental Shelf ◽  
Continental Slope ◽  
Continental Margin ◽  
Western Europe ◽  
Seismic Refraction ◽  
Continental Drift ◽  
Marine Geology ◽  
North East ◽  
The North ◽  
Episodic Evolution

A geological reconnaissance has been made of the continental slope of western Europe between the Faeroe Isles and Lisbon by means of a 60 kj reflexion profiler, supplemented by Boomer profiles and extensive Asdic (side-looking sonar) coverage of the continental shelf. A tentative interpretation of these profiles has been made by references to available rock samples and seismic refraction data. The first-formed continental slope deposits of the north-east Atlantic appear to be Cretaceous in age. Massive erosion (particularly of the continental shelf) preceded the Tertiary phase of downwarping which allowed upbuilding and outbuilding of the continental margin and was followed by a latest-Tertiary and Quaternary phase of important faulting, canyon erosion, slumping and deposition. This episodic evolution of the European continental margin is thought to indicate two phases of continental drift. In contrast to the ground west of the British Isles and France the steep and narrow northern and western continental margins of Iberia show only a little upbuilding and only local outbuilding. The work was done from aboard R.R.S. Discovery II or R.R.S. Discovery (with the exception of a Sparker profile obtained by H.M.T.S. Alert ), the powerful profiler being used in 1965, the Asdic on many cruises between 1958 and 1967.

The Medieval Sea

2007 ◽  
Author(s):  
Susan Rose
Keyword(s):  
Fifteenth Century ◽  
North Sea ◽  
Western Europe ◽  
English Channel ◽  
Naval Warfare ◽  
Secondary Literature ◽  
The Caribbean ◽  
The Mediterranean ◽  
Late Fifteenth

This book provides an accessible study of how peoples bordering the Mediterranean, North Sea, English Channel and eastern Atlantic related to the sea in all its aspects. This book surveys how the peoples bordering the Mediterranean, North Sea, English Channel and eastern Atlantic related to the sea in all its aspects between approximately 1000-1500 A.D.How was the sea represented in poems and other writings? What kinds of boats were used and how were they built? How easy was it to navigate on short or long passages? Was seaborne trade crucial to the economy of this area? Did naval warfare loom large in the minds of medieval rulers? What can be said more generally about the lives of those who went to sea or who lived by its shores? These are the major questions which are addressed in this book, which is based on extensive research in both maritime archives and also in secondary literature. It concludes by pointing out how the relatively enclosed maritime world of Western Europe was radically changed by the voyages of the late fifteenth century across the Atlantic to the Caribbean and round Africa to India.

scholarly journals Stability of a buoyancy-driven coastal current at the shelf break

2002 ◽  
Vol 452 ◽  
pp. 97-121 ◽  
Author(s):  
C. CENEDESE ◽  
P. F. LINDEN
Keyword(s):  
Continental Shelf ◽  
Continental Slope ◽  
Unstable Mode ◽  
Shelf Break ◽  
Coastal Current ◽  
Surface Currents ◽  
Flat Bottom ◽  
Vertical Boundary ◽  
Axisymmetric Disturbances ◽  
A Current

Buoyancy-driven surface currents were generated in the laboratory by releasing buoyant fluid from a source adjacent to a vertical boundary in a rotating container. Different bottom topographies that simulate both a continental slope and a continental ridge were introduced in the container. The topography modified the flow in comparison with the at bottom case where the current grew in width and depth until it became unstable once to non-axisymmetric disturbances. However, when topography was introduced a second instability of the buoyancy-driven current was observed. The most important parameter describing the flow is the ratio of continental shelf width W to the width L* of the current at the onset of the instability. The values of L* for the first instability, and L*−W for the second instability were not influenced by the topography and were 2–6 times the Rossby radius. Thus, the parameter describing the flow can be expressed as the ratio of the width of the continental shelf to the Rossby radius. When this ratio is larger than 2–6 the second instability was observed on the current front. A continental ridge allowed the disturbance to grow to larger amplitude with formation of eddies and fronts, while a gentle continental slope reduced the growth rate and amplitude of the most unstable mode, when compared to the continental ridge topography. When present, eddies did not separate from the main current, and remained near the shelf break. On the other hand, for the largest values of the Rossby radius the first instability was suppressed and the flow was observed to remain stable. A small but significant variation was found in the wavelength of the first instability, which was smaller for a current over topography than over a flat bottom.

scholarly journals Perkembangan Fasies Sedimen Formasi Mamberamo Berumur Miosen Akhir-Pliosen di Cekungan Papua Utara

2019 ◽  
Vol 20 (1) ◽  
pp. 37
Author(s):  
David Victor Mamengko ◽  
Yoga B.Sendjadja ◽  
Budi Mulyana ◽  
Hermes Panggabean ◽  
Iyan Haryanto ◽  
...  
Keyword(s):  
Carbonaceous Shale ◽  
Upper Miocene ◽  
Cross Bedding ◽  
Clastic Sediment ◽  
Clastic Sediments ◽  
New Perspective ◽  
Facies Succession

North Papua Basin is a fore arc basin located in northern coastal of Papua Island. This basin filled by Middle-Upper Miocene turbidite sediment and overlied by Upper Miocene – Quarternary clastic sediment. Upper Miocene – Quaternary clastic sediments (Mamberamo Formation) composed by interbedding conglomerate, sandstone and shale as molasses deposit. A detailed stratigraphic study was performed to identify facies and its association of the Mamberamo Formation to that give a new perspective on the characteristics and development of facies succession of Lower Mamberamo Formation. Result  shows that the Lower Mamberamo Formation consists of three facies: A) cross bedding sandstone (subtidal), B) heterolothic silty shale (intra-tidal), C) carbonaceous shale (supra-tidal) deposited on Late Miocen to Plio-Pleistocene during centra range orogeny (syn-orogeny) as molasses deposits.Keywords: Fore arc basin, North Papua Basin, Mamberamo Formation, molasse deposits.

scholarly journals On the occurrence and behaviour of two little-known barnacles, Hexelasma hirsutum and Verruca recta, from the continental slope

1958 ◽  
Vol 37 (3) ◽  
pp. 633-647 ◽  
Author(s):  
A. J. ◽  
Eve C. Southward ◽  
L. H. N. Cooper
Keyword(s):  
Continental Shelf ◽  
Continental Slope ◽  
British Isles ◽  
The South ◽  
South West

The fauna of the continental shelf and slope between Ireland and Spain has been described by Le Danois (1948), but very little faunistic work has been carried out in the area recently. Since R.V. ‘Sarsia’ was brought into service at Plymouth there have been several opportunities of investigating that part of the slope lying to the south-west of the British Isles. It has been found that, in addition to beds of coral, quite extensive exposures of rocks, stones and gravel occur between 200 and 1000 fathoms. There is a rich epifauna in this area and barnacles are one of the dominant groups.

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