Rockall Basin

The Rockall Basin is a large (approximately 800 by 150 kilometres (500 by 90 mi)) sedimentary basin that lies beneath the deepwater bathymetric feature, the Rockall Trough. Both are named after Rockall, a rocky islet lying 301.4 km (187.3 mi) west of St Kilda. The basin is flanked to the northwest by the Rockall High, to the southeast by the Porcupine High, to the north by the Wyville-Thomson Ridge and to the southwest by the Porcupine Abyssal Plain.

Geological structure

The nature of the crust beneath the Rockall Trough has long been a matter of debate.[1][2] Originally thought to be oceanic crust, it is now generally considered to be highly stretched continental crust. However, some groups of researchers continue to favour either oceanic or transitional style crust, particularly at the southern end of the basin.

The Rockall Basin forms part of a chain of highly extended Mesozoic rift basins between the Charlie–Gibbs and Senja fracture zones. It includes: the Faroe-Shetland Basin, the Møre Basin, and the Vøring Basin. There are indications that the Rockall Basin developed within an earlier rift system, which is likely to be of Triassic to Middle Jurassic in age, by analogy with the nearby Slyne-Erris Basins. The age of the main rift phase in the Rockall Basin is strongly debated, with Late Jurassic, Early-, Mid- and Late Cretaceous all being suggested.

During the Jurassic period, the Rockall Basin formed a seaway between the emergent Rockall-Hatton landmass (equivalent to the modern submerged Rockall Bank) and the emergent Hebrides Platform (comprising the modern Outer Hebrides).[3]

One of the features of the Rockall Basin is the Anton Dohrn Seamount. It lies 600 metres (2,000 ft) beneath the surface, rising 1,500 metres (4,900 ft) from the surrounding seabed. The Rockall Plateau finished forming approximately 55 million years ago, a continental block that lies between Greenland and Europe when the ancient continent of Laurasia was split apart by prolonged rifting.[4] The Rockall islet is the highest point of the plateau, rising 17.15 m (56 ft 3 in) above sea level.[5] It is made of a type of peralkaline granite.

Economic geology

To date, there has been comparatively little drilling to explore for oil and gas within the Rockall Basin and only two discoveries have been made: Benbecula in the northern UK Rockall (Shell originally Enterprise Oil)[6] and Dooish in the northern Irish Rockall (Shell originally Enterprise Energy Ireland).[7] The discoveries show that, at least locally, there is a working petroleum system. Rights to exploit these resources are disputed between the United Kingdom, Ireland, Iceland and the Faroe Islands (a possession of Denmark). This topic is addressed in Rockall Bank dispute.

See also

References

  1. ^ Stoker, M. S.; Hitchen, K. (2003). "The Rockall-Porcupine Margin". European Margin Sediment Dynamics: Side-Scan Sonar and Seismic Images. Berlin: Springer Verlag. pp. 161–172. ISBN 3-540-42393-1.
  2. ^ Klingelhofer, F.; Edwards, R.A.; Hobbs, R.W.; England, R.W. (2005). "Crustal structure of the NE Rockall Trough from wide-angle seismic data modeling". Journal of Geophysical Research. 110 B11105. doi:10.1029/2005JB003763.
  3. ^ Barron, J.M.; Lott, G.K.; Riding, J.B. (2012). "Stratigraphical framework for the Middle Jurassic strata of Great Britain and the adjoining continental shelf". British Geological Survey Research Report. 11 (6): 1–9. ISBN 9780852726952.
  4. ^ Sutherland, D.S., ed. (1982). Igneous Rocks of the British Isles. Wiley. ISBN 978-0471278108.
  5. ^ Alderson, Reevel (8 October 2014). "Rockall: Smaller, but in the same place". BBC News. Archived from the original on 8 October 2014. Retrieved 7 September 2025.
  6. ^ Schofield, N.; Jolley, D.; Holford, S.; Archer, S.; Watson, D.; Hartley, J.; Howell, J.; Muirhead, D.; Underhill, J.; Green, P. (2018). "Challenges of future exploration within the UK Rockall Basin". In Levell, B.; Bowman, M. (eds.). Petroleum Geology of NW Europe 50 Years of Learning : Proceedings of the 8th Petroleum Geology Conference. Geological Society. doi:10.1144/PGC8.37. ISBN 9781786202772.
  7. ^ Jackson, C.A.-L.; Magee, C.; Jacquemyn, C. (2020). "Rift-related magmatism influences petroleum system development in the NE Irish Rockall Basin, offshore Ireland". Petroleum Geoscience. 26: 611–524. doi:10.1144/petgeo2018-020.

Further reading

  • Haszeldine, R.S.; Russell, M.J. (1987). "The Late Carboniferous northern North Atlantic Ocean: implications for hydrocarbon exploration from Britain to the Arctic". In Brooks, J.; Glennie, K.W. (eds.). Petroleum Geology of North West Europe. London: Graham and Trotman. pp. 1163–1175. ISBN 978-0860107033.
  • Naylor, D.; Shannon, P.M.; Murphy, N. (1999). Irish Rockall Basin region – a standard structural nomenclature system. Stationery Office, Dublin. ISBN 978-0707662893. Petroleum Affairs Division, Dublin, Special Publications. 1/99.
  • Morewood, N.C.; Mackenzie, G.D.; Shannon, P.M.; O'Reilly, B.M.; Readman, P.W.; Makris, J. (2005). "The crustal structure and regional development of the Irish Atlantic Margin". In Dore, A.G.; Vining, B.A. (eds.). Petroleum Geology: North-West Europe and Global Perspectives – Proceedings of the 6th Petroleum Geology Conference. London: Geological Society. pp. 1023–1033. ISBN 978-1862392434.

56°00′N 12°00′W / 56.000°N 12.000°W / 56.000; -12.000

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