Gravity Flow Deposits in the Deep Rockall Trough, Northeast Atlantic

  • Aggeliki Georgiopoulou
  • Sara Benetti
  • Patrick M. Shannon
  • Peter D. W. Haughton
  • Stephen McCarron
Conference paper
Part of the Advances in Natural and Technological Hazards Research book series (NTHR, volume 31)

Abstract

The north-western margin of the Irish Rockall Trough in the Northeast Atlantic is dominated by the scarps of the Rockall Bank Mass Flow (RBMF) which extends towards the centre of the Rockall Trough, whereas the eastern margin is incised by numerous canyons that have no obvious associated fans at the foot of the slope. Terminal lobes associated with the glaciogenic Donegal-Barra Fan extend into the Rockall Trough from the northeast, whereas in the southwest the seafloor is dominated by the Feni Drift, a giant contourite drift formed by ocean bottom currents which was truncated by the sidewalls and depositional lobes of the RBMF. In June 2010 the RV Celtic Explorer cruise CE10008 collected the first comprehensive set of piston cores from the Irish sector of the deep Rockall Trough. Here we report on a sub-set of those cores recovered from across and beyond the bathymetric expression of the RBMF eastern outer limit in order to determine whether gravity flows were released during this event and whether they have traversed across the basin. The cores, taken in water depths of nearly 3,000 m, reveal that significant coarse sediment (up to coarse sand) was emplaced on the deep basin floor by both turbidity currents and bottom currents. We identify several discrete turbidite sand and silt deposits with geochemical signatures that point to different source areas. The youngest two appear to have been generated from the area occupied by the RBMF to the west during the Holocene. The remaining turbidite beds came from an easterly or northeasterly source and tie back to the Donegal-Barra Fan and are probably glacially related. Between the two periods we find a thick (>1.5 m) contouritic sand, possibly formed by bottom current reworking of the Feni Drift.

Keywords

Rockall Bank Mass Flow Donegal-Barra Fan Turbidite Contourite Provenance 

References

  1. Armishaw JE, Holmes RW, Stow DAV (1998) Morphology and sedimentation on the Hebrides slope and Barra Fan, NW UK continental margin. In: Stoker MS, Evans D, Cramp A (eds) Geological processes on continental margins: sedimentation, mass-wasting and stability, Geological Soceity, London, Special Publication 129, pp 81–104Google Scholar
  2. Chapman MR, Shackleton NJ (2000) Evidence of 550-year and 1000-year cyclicities in North Atlantic circulation patterns during the Holocene. The Holocene 10:287–291CrossRefGoogle Scholar
  3. Dunlop P, Shannon R, Quinn R, McCabe AM, Doyle E (2010) Marine geophysical evidence for ice sheet extension on the Malin Shelf: new evidence for the western limits of the British Irish Ice Sheet. Mar Geol 276:86–99CrossRefGoogle Scholar
  4. Elliott GM, Shannon PM, Haughton PDW, Praeg D, O’Reilly B (2006) Mid- to late Cenozoic canyon development on the eastern margin of the Rockall Trough, offshore Ireland. Mar Geol 229:113–132CrossRefGoogle Scholar
  5. Elliott GM, Shannon PM, Haughton PDW, Øvrebø LK (2010) The Rockall Bank mass flow: collapse of a moated contourite drift onlapping the eastern flank of the Rockall Bank, west of Ireland. Mar Petrol Geol 27:92–107CrossRefGoogle Scholar
  6. Faugères J-C, Gonthier E, Grousset F, Poutiers J (1981) The Feni Drift: the importance and meaning of slump deposits on the eastern slope of the Rockall Bank. Mar Geol 40:49–57CrossRefGoogle Scholar
  7. Flood RD, Hollister CD, Lonsdale P (1979) Disruption of the Feni sediment drift by debris flows from Rockall Bank. Mar Geol 32:311–334CrossRefGoogle Scholar
  8. Masson DG, Plets RMK, Huvenne VAI, Wynn RB, Bett BJ (2010) Sedimentology and depositional history of Holocene sandy contourites on the lower slope of the Faroe-Shetland channel, northwest of the UK. Mar Geol 268:85–96CrossRefGoogle Scholar
  9. Naylor D, Shannon PM (2011) Petroleum geology of Ireland. Dunedin Academic Press, Edinburgh, 262 ppGoogle Scholar
  10. New AL, Smythe-Wright D (2001) Aspects of the circulation in the Rockall Trough. Cont Shelf Res 21:777–810CrossRefGoogle Scholar
  11. O’Reilly BM, Shannon PM, Readman PW (2007) Shelf to slope sedimentation processes and the impact of Plio-Pleistocene glaciations in the northeast Atlantic, west of Ireland. Mar Geol 238:21–44CrossRefGoogle Scholar
  12. Øvrebø LK, Haughton PDW, Shannon PM (2005) Temporal and spatial variations in late quaternary slope sedimentation along the undersupplied margins of the Rockall Trough, offshore west Ireland. Norw J Geol 85:279–294Google Scholar
  13. Sacchetti F, Benetti S, Georgiopoulou A, Dunlop P, Quinn R (2011) Geomorphology of the Irish Rockall Trough, North Atlantic Ocean, mapped from multibeam bathymetric and backscatter data. J Maps 2011:60–81Google Scholar
  14. Stoker MS, Praeg D, Hjelstuen BO, Laberg JS, Nielsen T, Shannon PM (2005) Neogene stratigraphy and the sedimentary and oceanographic development of the NW European Atlantic margin. Mar Petrol Geol 22:977–1005CrossRefGoogle Scholar
  15. Tucker ME (1991) Sedimentary petrology: an introduction to the origin of sedimentary rocks, 2nd edn. Blackwell Science Ltd., London, p 260Google Scholar
  16. Unnithan V, Shannon PM, McGrane K, Readman PDW, Jacob AWB, Keary R, Kenyon NH (2001) Slope stability and sediment redistribution in the Rockall Trough: constraints from GLORIA. In: Shannon PM, Haughton PDW, Corcoran DV (eds) The petroleum exploration of Ireland’s offshore basins, vol 188. Geological Soceity, London, Special Publication, pp 439–454Google Scholar
  17. Vorren TO, Laberg JS (2001) Late quaternary sedimentary processes and environment on the Norwegian-Greenland Sea continental margins. In: Martinsen OJ, Dreyer T (eds) Sedimentary environments offshore Norway-palaeozoic to recent. Elsevier, Amsterdam, pp 451–456Google Scholar

Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Aggeliki Georgiopoulou
    • 1
  • Sara Benetti
    • 2
  • Patrick M. Shannon
    • 1
  • Peter D. W. Haughton
    • 1
  • Stephen McCarron
    • 3
  1. 1.UCD School of Geological SciencesUniversity College DublinDublin 4Ireland
  2. 2.School of Environmental SciencesUniversity of UlsterColeraineUK
  3. 3.Department of GeographyNational University of IrelandMaynoothIreland

Personalised recommendations