Lyell Collection
Geological Society, London, Special Publications
Lyell Centre  |   Lyell Collection  |   Subscriptions   |   Geological Society  |   Email alerts  |   Online bookshop  |   Help

Keywords:
Author:
Advanced search>>
This Article
Right arrow Full Text (PDF)
Right arrow References
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Martinsen, O. J.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation
Geological Society, London, Special Publications; 1989; v. 41; p. 167-177;
DOI: 10.1144/GSL.SP.1989.041.01.13
© 1989 Geological Society of London

Selected Delta Case Studies

Styles of soft-sediment deformation on a Namurian (Carboniferous) delta slope, Western Irish Namurian Basin, Ireland

O. J. Martinsen

Geologisk Institutt Avd. A, University of Bergen, Allégaten 41, 5007 Bergen, Norway

Soft-sediment deformation features from a delta-slope succession exposed in the Western Irish Namurian Basin, Ireland, are described and related to three main styles of deformation: (i) slumping, (ii) sliding and (iii) water-escape structures. While (i) and (ii) were formed by near-surface gravitational gliding of sediment, (iii) was formed by mainly vertical motion of sediment and escaping pore fluids. Deformation structures formed by slumping include slump folds and large- and small-scale faults, internal shear surfaces, deformation of early calcareous concretions and boudinage. The slumps were initially dominated by plastic deformation, whereas brittle deformation dominated the late stages. Deformation structures formed by sliding are mainly macroscopic faults, but microfaults and slide folds also formed locally. The slides were at all stages dominated by brittle deformation. Water-escape structures include mud and sand dykes and volcanoes, collapse depressions, mud diapirs and small-scale loading. These structures can be either related to or independent of slumping and sliding. While slumps are not restricted to any particular part of the delta slope, the occurrence of slides is, to a large degree, dependent upon grain size. Mud slides only occur on the muddy upper delta slope, while sand slides are only found on the lower delta slope. Water-escape structures tend to be more common on the lower delta slope.





This article has been cited by other articles:


Home page
 Geological Society, London, Special PublicationsHome page
M. R. Shultz, A. Fildani, T. D. Cope, and S. A. Graham
Deposition and stratigraphic architecture of an outcropping ancient slope system: Tres Pasos Formation, Magallanes Basin, southern Chile
Geological Society, London, Special Publications, 2005; 244: 27 - 50.
[Abstract] [PDF]

Home page
 Petroleum GeoscienceHome page
I. Moretti, S. Calassou, P. Victor, M. Molinaro, and L. Maerten
Syn-sedimentary shear zones
Petroleum Geoscience, 2003; 9: 221 - 232.
[Abstract] [Full Text] [PDF]

Home page
 Geological Society, London, Special PublicationsHome page
G. Shanmugam, R. B. Bloch, S. M. Mitchell, J. E. Damuth, G. W. J. Beamish, R. J. Hodgkinson, T. Straume, S. E. Syvertsen, and K. E. Shields
Slump and debris-flow dominated basin-floor fans in the North Sea: an evaluation of conceptual sequence-stratigraphical models based on conventional core data
Geological Society, London, Special Publications, 1996; 103: 145 - 176.
[Abstract] [PDF]