a) Multichannel seismic reflection profile from the western flank of the southern Rockall Trough highlighting the giant, elongate, Feni Ridge sediment drift, associated sediment waves, and an erosional moat adjacent to the Rockall bank. Note that the main build-up phase of the Feni Ridge is preserved in the RPb megasequence, with major basin-margin onlap onto the C30 boundary. The original morphology of the drift has since been modified by erosion linked to the C10 Unconformity. Syn-sedimentary faulting is common in the RPb megasequence
b) Multichannel seismic reflection profile from the eastern flank of the southern Rockall Trough showing relatively flat-lying, continuous reflections within the Neogene succession. However, on close inspection, there is low-angle onlap of RPb sediments onto the C20 boundary, whilst C10 is cut into the upper part of the RPb succession. The RPa sediments thicken towards the foot of Porcupine Bank, and may include highly reflective ponded turbidites.
c) High-resolution profile from the SW Rockall Trough showing the highly reflective zone of C20, and the projected location of DSDP site 610 which is interpreted to have penetrated this boundary (cf.
Fig. 20).
d) Very high-resolution seismic reflection profile from the SW Rockall Trough at DSDP site 610, showing correlation with the borehole. At site 610, the C20 boundary is probably obscured by a sea-bed multiple. However, the sharp change in seismic character at about 250ms (TWTT), from an upper stratified section to a lower reflection-free signature most likely coincides with the C10 boundary (Stoker
et al. 2001).
Reference
McDonnell, A. & Shannon, P.M. 2001. Comparative Tertiary stratigraphic evolution of the Porcupine and Rockall basins. . In: Shannon, P.M., Haughton, P.D.W. & Corcoran, D.V. (eds),
The Petroleum Exploration of Ireland's Offshore Basins. Geological Society, London, Special Publication,
188, 323-344.
Stoker, M.S., van Weering, T.C.E. & Svaerdborg, T. 2001. A Mid- to Late Cenozoic tectonostratigraphic framework for the Rockall Trough.
In: Shannon, P.M., Haughton, P.D.W. & Corcoran, D.V. (eds), The Petroleum Exploration of Ireland's Offshore Basins. Geological Society, London, Special Publication,
188, 411-438.
