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The geology, crustal structure and evolution of the Rockall Trough and the Faeroe-Shetland Channel

Published online by Cambridge University Press:  05 December 2011

Roger A. Scrutton
Roger A. Scrutton
Affiliation:
Grant Institute of Geology, West Mains Road, Edinburgh EH9 3JW, Scotland
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Synopsis

From direct sampling, the deeper Rockall Trough and Faeroe-Shetland Channel are known to have a Tertiary-Quaternary sedimentary sequence up to 3000 m thick, which is in places, particularly in the north, underlain by early Tertiary basaltic volcanic rocks. The seamounts in the Rockall Trough are of basic volcanics of probable Upper Cretaceous age. The eastern shelf areas have a rifted basement of Precambrian-Devonian (-?Carboniferous) age, overlain by Permian + Mesozoic sedimentary rocks that reach 5000 m in thickness in rift basins. Tertiary sediments thicken rapidly from the shelf into deep water. The western shelf areas have extensive early Tertiary basalts from the Faeroe Islands to the southern part of Rockall Bank. A thin Tertiary—Quaternary cover exists and Precambrian basement lies beneath.

The pre-Tertiary geology of the deep water areas and the overall crustal structure have been inferred from geophysical investigations. In the Rockall Trough the crust is of oceanic thickness, about 6 km, but it is probably slightly thicker beneath the Faeroe-Shetland Channel. This fact, coupled with the size of the channel compared with other small ocean basins and the knowledge that fully developed oceanic crust exists just outside the mouth of the Rockall Trough, strongly suggests that at least parts of the deep water areas are floored by oceanic crust. However, seismic reflection and magnetic anomaly profiles do not yield observations characteristic of normal oceanic crust.

The age of any oceanic crust in the Rockall Trough and Faeroe-Shetland Channel is equivocal. Between 54° and 59° N a succession of largely sedimentary rocks up to 3000 m in thickness occurs between the Tertiary and the acoustic basement. To the north this succession is masked on seismic profiles by early Tertiary basalts but it is probably present; to the south it is interrupted by a series of acoustically opaque basement ridges. With slow sedimentation rates, this succession could extend back to the late Palaeozoic, but with rapid rates, only to the mid-Upper Cretaceous. An age of mid-Lower to mid-Upper Cretaceous for oceanic crust, equal to that of the ocean crust outside the mouth of the Rockall Trough, is accepted here. Although rapid subsidence and infill in Upper Cretaceous time is not characteristic of major shelf basins around Britain, it may be acceptable for the Rockall Trough and Faeroe-Shetland Channel if they are underlain by oceanic crust rather than continental crust.

A likely model for the formation of the Rockall Trough and Faeroe-Shetland Channel is of continental rifting and subsidence from late Palaeozoic or earliest Mesozoic to mid-Cretaceous time, then sea-floor spreading in Albian (c.105My)–Santonian (c.85 My) time, accompanied and immediately followed by rapid subsidence and deposition. The Tertiary was heralded by widespread basaltic igneous activity which briefly arrested subsidence, but was largely a period of subsidence without sedimentation keeping pace.

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. 7 - 26
Copyright
Copyright © Royal Society of Edinburgh 1986

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References

Bott, M. H. P. 1984. Deep structure and origin of the Faeroe-Shetland Channel. In Petroleum Geology of the North European Margin, ed. Spencer, A. M., pp. 341–347. London: Graham & Trotman.CrossRefGoogle Scholar
Bott, M. H. P. & Smith, P. J. 1984. Crustal structure of the Faeroe-Shetland Channel. Geophysical Journal, Royal Astronomical Society, London 76, 383–399.CrossRefGoogle Scholar
Cochran, J. R. 1981. The Gulf of Aden: structure and evolution of a young ocean basin and continental margin. Journal of Geophysical Research 86, 263–288.CrossRefGoogle Scholar
Cochran, J. R. 1983. A model for the development of the Red Sea. Bulletin of the American Association Petroleum Geology 67, 41–69.Google Scholar
Cole, G. A. J. 1897.On rock specimens dredged on the Rockall Bank. Transactions of the Royal Irish Academy 31, 58.Google Scholar
de Charpal, O., Montadert, L., Guennoc, P and Roberts, D. G. 1978. Rifting, crustal attenuation and subsidence in the Bay of Biscay. Nature, London 275, 706–711.CrossRefGoogle Scholar
de Graciansky, P. C, Poag, C. W. et al. 1984. Initial Reports of the Deep Sea Drilling Project, Vol.80, Washington D.C.: United States Government Printing Office.Google Scholar
Dewey, J. F. 1981. Plate tectonics and the evolution of the British Isles. Journal of the Geological Society of London 138, 371–414.Google Scholar
Hanisch, J. 1984. The Cretaceous opening of the North-East Atlantic. Tectonophysics 101, 1–23.Google Scholar
Harrison, R. K., Jeans, C. V. & Merriman, R. J. 1979. Mesozoic igneous rocks, hydrothermal mineralisation and volcanogenic sediments in Britain and adjacent regions. Bulletin of the Geological Survey of Great Britain 70, 57–69.Google Scholar
Haszeldine, R. S. 1984. Carboniferous North Atlantic palaeogeography: stratigraphic evidence for rifting, not megashear or subduction. Geological Magazine 121, 443–463.CrossRefGoogle Scholar
Jones, E. J. W., Ewing, M., Ewing, J. I. & Eittreim, S. L. 1970. Influences of Norwegian Sea Overflow Water on sedimentation in the Northern North Atlantic and Labrador Sea. Journal of Geophysical Research 75, 1655–1680.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. & Ramsay, A. T. S. 1982. Volcanic ash deposits of early Eocene age from the Rockall Trough. Nature, London 299, 342–344.CrossRefGoogle Scholar
Keen, C. E. 1982. The Continental Margins of Eastern Canada: A Review. In Dynamics of Passive Margins, ed. Scrutton, R. A., pp. 45–58. Geodynamics Series Vol.6. Washington D.C.: American Geophysics Union.CrossRefGoogle Scholar
Kidd, R., Ruddiman, E. et al., in prep. Initial Reports of the Deep Sea Drilling Project, Vol.94.Washington D.C.: United States Government Printing Office.Google Scholar
Kristoffersen, Y. 1978. Sea-floor spreading and the early opening of the North Atlantic. Earth and Planetary Science Letters 38, 273–290.CrossRefGoogle Scholar
Laughton, A. S., Berggren, W. A. et al. 1972. Initial Reports of the Deep Sea Drilling Project Vol.12. Washington D.C.: United States Government Printing Office.Google Scholar
Lovell, J. P. B. 1979. The British Isles through Geological Time. London: George Allen & Unwin.Google Scholar
Masson, D. G. & Kidd, R. J. (in press). Tertiary seismic stratigraphy of the southern Rockall Trough. Initial Reports of the Deep Sea Drilling Project, Vol.94 Washington D.C.: United States Government Printing Office.Google Scholar
Masson, D. G. & Miles, P. R. 1984. Mesozoic sea-floor spreading between Iberia, Europe and North America. Marine Geology 56, 279–287.CrossRefGoogle Scholar
Miller, J. A., Roberts, D. G. & Matthews, D. H. 1973. Rocks of Grenville age from Rockall Bank. Nature, London 246, 61–62.Google Scholar
Naylor, D. & Shannon, P. M. 1982. The Geology of offshore Ireland and West Britain. London: Graham & Trotman.CrossRefGoogle Scholar
Nielsen, P. H. 1983. Geology and crustal structure of the Faeroe Islands—a review. In Structure and Development of the Greenland-Scotland Ridge, eds. Bott, M. H. P., Saxov, S., Talwani, M. & Thiede, J., pp. 77–90. NATO Conference, Series 4, Vol.8. New York: Plenum Press.CrossRefGoogle Scholar
Parsons, B. & Sclater, J.G. 1977. An analysis of the variation of ocean floor bathymetry and heat flow with age. Journal of Geophysical Research 82, 803–827.CrossRefGoogle Scholar
Price, I. & Rattey, R. P. 1984. Cretaceous tectonics off mid-Norway: implications for the Rockall and Faeroes-Shetland Troughs. Journal of the Geological Society of London 141, 985–992.CrossRefGoogle Scholar
Ridd, M. F. 1981. Petroleum geology west of the Shetlands. In Petroleum Geology of the Continental Shelf of North-West Europe, eds. Ming, L. V. & Hobson, G. D., pp. 414–425. London: Institute of Petroleum.Google Scholar
Ridd, M. F. 1983. Aspects of the Tertiary geology of the Faeroe-Shetland Channel. In Structure and Development of the Greenland-Scotland Ridge, eds. Bott, M. H. P., Saxov, S., Talwani, M. & Thiede, J., pp. 91–108. NATO Conference, Series 4, Vol.8. New York: Plenum Press.CrossRefGoogle 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., Ardus, D. A. & Dearnley, R. 1973. Precambrian rocks drilled from the Rockall Bank. Nature, London 244 21–23.Google Scholar
Roberts, D. G., Flemming, N. C, Harrison, R. K., Binns, P. & Snelling, J. J. 1974. Helen's Reef—a microgabbroic intrusion in the Rockall Intrusive Centre, Rockall Bank. Marine Geology 16, M21–M30.CrossRefGoogle 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
Bott, M. H. P. & Uruski, C. 1983. Structure and origin of the Wyville-Thomson Ridge. In Structure and Development of the Greenland-Scotland Ridge, eds. Bott, M. H. P., Saxov, S., Talwani, M. 133–159. NATO Conference, Series 4, Vol.8. New York: Plenum Press.CrossRefGoogle Scholar
Robinson, P. T., Lewis, B. T. R., Flower, M. F. J., Salisbury, M. H. & Schmincke, H.-U. 1983. Crustal accretion in the Gulf of California: an intermediate rate spreading axis. In Initial Reports of the Deep Sea Drilling Project, Vol.65, eds. Lewis, B. T. R., Robinson, P. et al. pp. 739–752. 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 N. Atlantic. In Petrology and Geochemistry of Continental Rifts, eds. Neumann, E. R. & Ramberg, I. B. pp. 173–179. Holland: D. Riedel.CrossRefGoogle Scholar
Sabine, P. A. 1965. Rockall—an unusual occurrence of Tertiary granite. Proceedings of the Geological Society of London 1621, 15.Google Scholar
Sclater, J. G. & Christie, P. A. F. 1980. Continental stretching: an explanation of the post mid Cretaceous subsidence of the central North Sea Basin. Journal of Geophysical Research 85, 3711–3739.CrossRefGoogle Scholar
Scrutton, R. A. 1972. Crustal structure of Rockall Plateau microcontinent. Geophysical Journal, Royal Astronomical Society 27, 259–275.CrossRefGoogle Scholar
Scrutton, R. A. 1984. Modelling of magnetic and gravity anomalies at Goban Spur, Northeastern Atlantic. In Initial Reports of the Deep Sea Drilling Project, Vol.80, eds. de Graciansky, P. C, Poag, C. W. et al., pp. 1141–1151. Washington D.C.: United States Government Printing Office.Google Scholar
Smith, P. J. & Bott, M. H. P. 1975. Structure of the crust beneath the Caledonian foreland and Caledonian belt of the North Scottish Shelf region. Geophysical Journal, Royal Astronomical Society 40, 187–205.CrossRefGoogle Scholar
Smythe, D. K. 1983. Faeroe-Shetland Escarpment and continental margin north of the Faeroes. In Structure and Development of the Greenland—Scotland Ridge, eds. Bott, M. H. P. Saxov, S., Talwani, M. & Thiede, J., pp. 109–119, NATO Conference, Series 4, Vol.8. New York: Plenum Press.CrossRefGoogle Scholar
Smythe, D. K., Chalmers, J. A., Skuce, A. G., Dobinson, A. & Mould, A. S. 1983. Early opening history of the North Atlantic—1. Structure and origin of the Faeroe-Shetland Escarpment. Geophysical Journal, Royal Astronomical Society 72, 373–378.CrossRefGoogle Scholar
Srivastava, S. 1978. Evolution of the Labrador Sea and its bearing on the early evolution of the North Atlantic. Geophysical Journal, Royal Astronomical Society 52, 313–357.CrossRefGoogle Scholar
Stow, D. A. V. 1981. Sedimentary history and hydrocarbon potential of the continental margin north and west of the U.K. and Ireland. In Geology and Geophysics of the U.K. and Irish continental margin—Goban Spur to Rockall Bank, ed. Scrutton, R. A., pp. D1–D26. Edinburgh: University of Edinburgh, Department of Geology.Google Scholar
Talwani, M. & Eldholm, O. 1972. Continental margin off Norway: a geophysical study. Bulletin of the Geological Society of America 83, 3575–3606.CrossRefGoogle Scholar
Thiede, J. & Eldholm, O. 1983. Speculations about the palaeodepth of the Greenland-Scotland Ridge during Late Mesozoic and Cenozoic times. In Structure and Development of the Greenland- Scotland Ridge, eds. Bott, M. H. P., Saxov, S., Talwani, M. & Thiede, J., pp. 445–455. NATO Conference, Series 4, Vol.8. New York: Plenum Press.CrossRefGoogle Scholar
Vann, I. R. 1978. The siting of Tertiary vulcanicity. In Crustal evolution in northwestern Britain and adjacent regions, eds. Bowes, D. R. & Leake, B. E., pp. 393–414. Geological Journal, Special Issue 10.Google Scholar
Watts, A. B., Schreiber, B. C. & Habib, D. 1975. Dredged rocks from Hatton Bank, Rockall Plateau.Journal of the Geological Society of London 1311, 639–646.CrossRefGoogle Scholar
Whitmarsh, R. B., Langford, J. J., Buckley, J. S., Bailey, R. J. & Blundell, D. J. 1974. The crustal structure beneath Porcupine Ridge as determined by explosion seismology. Earth and Planetary Science Letters 22, 197–204.CrossRefGoogle Scholar
Williams, H. 1978. Geological development of the northern Appalachians: its bearing on the evolution of the British Isles. In Crustal evolution in northwestern Britain and adjacent regions, eds. Bowes, D. R. & Leake, B. E., pp. 1–22. Geological Journal, Special Issue 10.Google Scholar
Zeigler, P. A. 1982. Geological Atlas of Western and Central Europe. The Hague: SIPM.Google Scholar