|
Article |
1 Amerada Hess Ltd, 33 Grosvenor Place, London SW1X 7HY, UK
2 Network Stratigraphic Consultants Ltd, Unit 5, The Enterprise Centre, Cranborne Road, Potters Bar EN6 3DQ, UK
A previously unrecorded outlier of Tertiary sediments is described from blocks 42/29 and 47/4b on the northeast corner of the East Midlands Shelf, southern North Sea, UK. Biostratigraphy in well 47/4b-6 indicates the presence of lateral time equivalents of the Horda, Balder-Sele and Lista Formations, the only occurrence of Tertiary sediments on the East Midlands Shelf. The outlier is 50 km from the Humberside coast, 30 km west of the nearest Tertiary sediments. The Tertiary strata subcrop thin Recent deposits over an area of 104 km2, and reach a maximum thickness of 700 m. Erosive truncation of these sediments shows that they are remnants of a more extensive Palaeogene cover on the East Midlands Shelf and they constrain the timing of inversion on the Dowsing Fault Zone and growth of the Sole Pit High. The outlier is compartmentalized in terms of structural style into an unfaulted westerly portion which is oval in outline, and an adjoining northwest-southeast trending graben. The contrasting geometries of these compartments reflect salt-controlled synclinal folding and thin-skinned extensional faulting detaching on Triassic salt respectively. Both mechanisms are effects of basinwards sliding of the Sole Pit High Mesozoic section upon Permian salt, triggered by Tertiary inversion on the Dowsing Fault Zone. Unconformities associated with the outlier indicate an initial, intra-Campanian phase of inversion, followed by two later episodes which may correlate with late Maastrichtian and intra-Miocene events recorded further south and east. The Palaeogene sediments within the outlier represent part of the eroded cover of the East Midlands Shelf predicted to have been present by sonic log-based studies of apparent exhumation.
Keywords: North Sea, detachment faults, salt tectonics, unconformities.
This article has been cited by other articles:
 |
|
 |
|
  J. R. Underhill Role of intrusion-induced salt mobility in controlling the formation of the enigmatic 'Silverpit Crater', UK Southern North Sea Petroleum Geoscience, 2009; 15: 197 - 216. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. A. Stewart Salt tectonics in the North Sea Basin: a structural style template for seismic interpreters Geological Society, London, Special Publications, 2007; 272: 361 - 396. [Abstract] [PDF]
|
|
|
|
 |
|
 S.A. Stewart and P.J. Allen 3D seismic reflection mapping of the Silverpit multi-ringed crater, North Sea Geological Society of America Bulletin, 2005; 117: 354 - 368. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. F. Green, P. F. GREEN, K. THOMSON, and J. D. HUDSON Recognition of tectonic events in undeformed regions: contrasting results from the Midland Platform and East Midlands Shelf, Central England Journal of the Geological Society, 2001; 158: 59 - 73. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. J. PEARSON and M. A. RUSSELL Subsidence and erosion in the Pennine Carboniferous Basin, England: lithological and thermal constraints on maturity modelling Journal of the Geological Society, 2000; 157: 471 - 482. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. W. Holliday Palaeotemperatures, thermal modelling and depth of burial studies in northern and eastern England Proceedings of the Yorkshire Geological Society, 1999; 52: 337 - 352. [Abstract] [PDF]
|
|
|
|
 |
|
 D. J. Evans Estimates of the eroded overburden and the Permian-Quaternay subsidence history of the area west of Orkney Scottish Journal of Geology, 1997; 33: 169 - 181. [Abstract] [PDF]
|
|
|
|
|
|
P. Japsen and P. JAPSEN Regional Neogene exhumation of Britain and the western North Sea Journal of the Geological Society, 1997; 154: 239 - 247. [Abstract] [PDF]
|
|
