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Geology of the Hebridean margin of the Rockall Trough

Published online by Cambridge University Press:  05 December 2011

E. J. W. Jones ,
R. G. Perry  and
J. L. Wild
E. J. W. Jones
Affiliation:
Department of Geological Sciences, University College London, Gower Street, London WC1E 6BT, England
R. G. Perry
Affiliation:
Department of Geological Sciences, University College London, Gower Street, London WC1E 6BT, England
J. L. Wild
Affiliation:
Department of Geological Sciences, University College London, Gower Street, London WC1E 6BT, England
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Synopsis

The geological structure and history of the Rockall Trough margin to the west of the Outer Hebrides (57°N-59°N) has been inferred from the analysis of bottom samples, seismic, sonar, magnetic, satellite altimeter and surface-ship gravity observations. Much of the continental shelf consists of a shallow platform of Precambrian Lewisian basement, covered by a thin (<300m) blanket of Cenozoic sediments. Apart from areas near the shelf break and immediately west of Lewis, the basement has not undergone the large-scale subsidence typical of many regions adjacent to the Rockall Trough. Beneath the outer shelf, the Lewisian dips steeply towards the deeper water and is covered by a westwardthickening succession (>3km) of Mesozoic and Cenozoic sediments.

The eastern margin of the Rockall Trough appears to have been well established as a site of deposition by the end of the Triassic. Further subsidence occurred during the late Jurassic and continued into the Cretaceous when the axial province of the Rockall Trough off the Hebrides was invaded by basic volcanic material. Subsequently, the region was profoundly affected by early Cenozoic igneous activity. The long-term buoyancy of the Lewisian basement under the Outer Hebridean platform and early-formed structural discontinuities within it have influenced the overall pattern of sediment accumulation and the distribution of volcanic activity along the margin. During the later stages of deposition, sedimentation was closely controlled by the presence of early Cenozoic volcanics, by bottom currents and by glacial processes.

Type
Research Article
Information
Proceedings of the Royal Society of Edinburgh, Section B: Biological Sciences , Volume 88: The Oceanography of the Rockall Channel , 1986 , pp. 27 - 51
Copyright
Copyright © Royal Society of Edinburgh 1986

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References

Belderson, R. H., Kenyon, N. H. & Wilson, J. B. 1973. Iceberg plough marks in the Northeast Atlantic. Palaeogeography, Palaeoclimatology, Palaeoecology 13, 215–224.CrossRefGoogle Scholar
B.G.S. 1981. Maps of solid geology of the Outer Hebrides (Uist and Barra); scale 1:100,000. The British Geological Survey.Google Scholar
B.G.S. 1984. Aeromagnetic maps at 1:250,000 scale, 56°-59° N, 6°-10° W (Tiree, Peach, Little Minch, St Kilda, Lewis and Geikie sheets). The British Geological Survey.Google Scholar
Bott, M. H. P., Armour, A. R., Himsworth, E. M., Murphy, T. & Wylie, G. 1979. An explosion seismology investigation of the continental margin west of the Hebrides, Scotland at 58°N. Tectonophysics 59, 217–231.Google Scholar
Bowes, D. R. 1978. Shield formation in early Precambrian times: The Lewisian complex. In Crustal evolution in northwestern Britain and adjacent regions, eds Bowes, D. R. & Leake, B. E., pp. 39–80. Geological Journal Special Issue 10, Geological Society of London.Google Scholar
Brewer, J. A., Matthews, D. H., Warner, M. R., Hall, J., Smythe, D. K. & Whittington, R. J. 1983. BIRPS deep seismic reflection studies of the British Caledonides. Nature, London 305, 206–210.CrossRefGoogle Scholar
Brown, J. W., Cleven, G. C, Klose, J. C, Lame, D. B. & Yamarone, C. A. 1979. Seasat low-rate data system. Science 204, 1407–1408.CrossRefGoogle ScholarPubMed
Cartwright, D. E. & Alcock, G. A. 1981. On the precision of sea surface elevations and slopes from Seasat altimetry of the Northeast Atlantic Ocean. In Oceanography from Space, ed. Gower, J. F. R., pp. 885–895. New York: Plenum Press.CrossRefGoogle Scholar
Dearnley, R. 1962. An outline of the Lewisian complex of the Outer Hebrides in relation to that of the Scottish mainland. Quarterly Journal of the Geological Society of London 118, 143–176.CrossRefGoogle Scholar
Dietrich, V. J. & Jones, E. J. W. 1980. Volcanic rocks from Rosemary Bank (Rockall Trough, NE Atlantic). Marine Geology 35, 287–297.CrossRefGoogle Scholar
Evans, D., Chesher, J. A., Deegan, C. E. & Fannin, N. G. T. 1982. The offshore geology of Scotland in relation to the I.G.S. shallow drilling programme, 1970–1978. Report of the Institute of Geological Sciences No. 81/12.Google Scholar
Harding, R. R., Merriman, R. J. & Nancarrow, P. H. A. 1984. St Kilda: An illustrated account of the geology. Report of the British Geological Survey 16, No. 7.Google Scholar
Haszeldine, R. S. 1984. Carboniferous North Atlantic palaeogeography: Stratigraphic evidence for rifting, not megashear or subduction. Geological Magazine 121, 443–463.Google Scholar
Haxby, W. F., Karner, G. D., LaBreque, J. L. & Weissel, J. K. 1983. Digital images of combined oceanic and continental data sets and their use in tectonic studies. EOS (Transactions, American Geophysical Union) 64, 995–1004.Google Scholar
Huthnance, J. M. 1986. The Rockall slope current and shelf edge processes. Proceedings of the Royal Society of Edinburgh 88B, 83–101.Google Scholar
Jones, E. J. W. 1978. Seismic evidence for sedimentary troughs of Mesozoic age on the Hebridean continental margin. Nature, London 272, 789–792.Google Scholar
Jones, E. J. W. 1981. Seismic refraction shooting on the continental margin west of the Outer Hebrides, NW Scotland. Journal of Geophysical Research 86, 11,553–11,574.Google Scholar
Jones, E. J. W., Ewing, M., Ewing, J. I. & Eittreim, S. L. 1970. Influence of Norwegian Sea overflow water on sedimentation in the northern North Atlantic and Labrador Sea. Journal of Geophysical Research 75, 1655–1680.Google Scholar
Jones, E. J. W., Mitchell, J. G. & Perry, R. G. 1986. Early Tertiary basaltic rocks from the continental shelf west of the Outer Hebrides, Northwest Scotland (in press).Google Scholar
Jones, E. J. W. &Ramsay, A. T. S. 1982. Volcanic ash deposits of early Eocene age from the Rockall Trough. Nature, London 299, 342–344.CrossRefGoogle Scholar
Jones, E. J. W., Ramsay, A. T. S., Preston, N. J. & Smith, A. C. S. 1974. A Cretaceous guyot in the Rockall Trough. Nature, London 251, 129–131.CrossRefGoogle Scholar
Jones, E. J. W., White, R. S., Hughes, V. J., Matthews, D. H. & Clayton, B. R. 1984. Crustal structure of the continental shelf off Northwest Britain from two-ship seismic experiments. Geophysics 49, 1605–1621.CrossRefGoogle Scholar
Matthews, D. J. 1939. Tables of the velocity of sound in pure water and sea water for use in echosounding and sound-ranging, 2nd edn. London: Hydrographic Department, Admiralty.Google Scholar
McGeary, S. & Warner, M. R. 1985. Seismic profiling the continental lithosphere. Nature, London 317, 795–797.CrossRefGoogle Scholar
McLean, A. C. 1978. Evolution of fault-controlled ensialic basins in northwestern Britain. In Crustal evolution in northwestern Britain and adjacent regions, eds. Bowes, D. R. & Leake, B. E., pp. 325–346. Geological Journal Special Issue 10, Geological Society of London.Google Scholar
Miller, J. A. & Mohr, P. A. 1965. Potassium-argon age determinations on rocks from St Kilda and Rockall. Scottish Journal of Geology 1, 93–99.CrossRefGoogle Scholar
Miller, K. G. & Tucholke, B. E. 1983. Development of Cenozoic abyssal circulation south of the Greenland-Scotland Ridge. In Structure and development of the Greenland-Scotland Ridge, eds. Bott, M. H. P., Saxov, S., Talwani, M. & Thiede, J., pp. 549–589. New York: Plenum Press.CrossRefGoogle Scholar
Ridd, M. F. 1981. Petroleum geology west of the Shetlands. In Petroleum Geology of the Continental Shelf of North-West Europe, eds.Illing, L. V. & Hobson, G. D., pp. 414–25. London: Institute of Petroleum.Google Scholar
Roberts, D. G. 1970. Recent geophysical investigations on the Rockall Plateau and adjacent areas. Proceedings of the Geological Society of London 1662, 87–93.Google Scholar
Roberts, D. G. 1975. Marine geology of the Rockall Plateau and Trough. Philosophical Transactions of the Royal Society of London 278A, 447–509.Google Scholar
Roberts, D. G., Hunter, P. M. & Laughton, A. S. 1977. Bathymetry of the Northeast Atlantic (Sheet 2); 1:2–4 million. Taunton: Hydrographic Department (Ministry of Defence).Google Scholar
Roberts, D. G., Masson, D. G. & Miles, P. R. 1981. Age and structure of the southern Rockall Trough: New evidence. Earth and Planetary Science Letters 52, 115–128.CrossRefGoogle Scholar
Roberts, D. G., Morton, A. C. & Backman, J. 1984. Late Paleocene-Eocene volcanic events in the northern North Atlantic Ocean. In Initial Reports of the Deep Sea Drilling Project, vol.81, pp. 913–923. Washington D.C.: United States Government Printing Office.Google Scholar
Russell, M. J. & Smythe, D. K. 1978. Evidence for an early Permian oceanic rift in the northern North Atlantic. In Petrology and geochemistry of continental rifts, eds. Neumann, E. R. & Ramberg, I. B., pp. 173–179. Holland: D. Reidel.CrossRefGoogle Scholar
Scrutton, R. A. 1972. The crustal structure of Rockall Plateau microcontinent. Geophysical Journal of the Royal Astronomical Society 27, 259–275.CrossRefGoogle Scholar
Scrutton, R. A. 1986. The geology, crustal structure and evolution of the Rockall Trough and the Faeroe- Shetland Channel. Proceedings of the Royal Society of Edinburgh 88B, 7–26.Google Scholar
Stewart, M. 1933. Notes on the geology of Sula Sgeir and the Flannan Islands. Geological Magazine 70, 110–116.Google Scholar
Sutherland, D. G. 1984. The submerged landforms of the St Kilda Archipelago, western Scotland. Marine Geology 58, 435–42.CrossRefGoogle Scholar
Tapley, B. D., Born, G. H. & Parke, M. E. 1982. The SEASAT altimeter data and its accuracy assessment. Journal of Geophysical Research 87, 3179–3188.Google Scholar
Vail, P. R., Mitchum, R. M. & Thompson, S. (III) 1977. Seismic stratigraphy and global changes of sea level, Part 4: Global cycles of relative changes of sea level. In Seismic stratigraphy— applications to hydrocarbon exploration, pp. 83–97. Tulsa: American Association of Petroleum Geologists, Memoir 26.Google Scholar
Watson, J. V. 1977. The Outer Hebrides: A geological perspective. Proceedings of the Geologists’ Association 88, 1–14.CrossRefGoogle Scholar
Westbrook, G. K. 1974. The South Harris magnetic anomaly. Proceedings of the Geologists’ Association 85, 1–12.CrossRefGoogle Scholar