Fault distribution and timing in the Central Irish Sea Basin

Izatt, Chris; Maingarm, Suvimol; Racey, Andrew

doi:10.1144/gsl.sp.2001.188.01.08

Cited by 5 publications

(3 citation statements)

References 17 publications

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“…Published seismic cross-sections (in twtt) and other data from the Peel, Kish Bank, Central Irish Sea, St Georges Channel, North Celtic Sea, Rockall, Slyne and Erris basins (e.g. Croker, 1995;Dancer et al, 1999;Dunford et al, 2001;Chapman et al, 1999;Floodpage et al, 2001;Izatt et al, 2001;Murdoch et al, 1995;Mackenzie et al, 2002) 11. Seismic interpretation from the western approaches to the English Channel from Evans et al (1990).…”

Section: Cover Sequence Thicknessmentioning

confidence: 99%

Three-dimensional gravity and magnetic modelling of the Irish sector of the NE Atlantic margin

2010

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A new 3D lithospheric model has been constructed using high-resolution gravity data from the Irish National Seabed Survey. The sedimentary component of the model incorporated density variations due to laterally varying overcompaction associated with Cenozoic denudation. After optimisation based on gravity inversion, regional crustal thickness variations were defined which are in reasonable agreement with the results of wide-angle seismic experiments. High crustal extension factors (β>5) characterise the deeper parts of the Rockall and Porcupine basins and in places the model indicates extreme stretching (β>10) beneath these basins. This could be because of instability in the gravity inversion, although other recent investigations have independently suggested similarly high extension factors. In contrast, the Hatton Basin is characterised by an apparent extension factor of about 2. The modelling resolves a pattern of NE-to NNE-trending local Mesozoic basins on the margins of the Rockall Trough, helping to delineate structures that were previously only sparsely sampled by seismic surveys. It appears possible that rifts with similar trends underlie the volcanic rocks which obscure the deeper parts of the Hatton Basin. The linear trends of the basins to the south and east of Ireland are interpreted to have been inherited from a basement fabric that was initially established during the late Precambrian assembly of this basement and subsequently subjected to Caledonian and Variscan reactivation. Magnetic modelling indicates that the variations in the thickness of the crystalline crust predicted by the gravity models can explain the regional magnetic anomaly patterns over the Rockall and Porcupine basins, but that significant additional magnetic material (probably igneous rocks of both Palaeogene and Cretaceous ages) is required to explain the anomalies in the Hatton Basin region. The magnetic signature of the Rockall Basin is distinctly different to that over the basement (of similar apparent thickness) formed during mid Cretaceous (C34N) opening of the ocean basin to the south. This is an impediment to hypotheses that invoke mid Cretaceous sea-floor spreading rather than intracontinental rifting to explain the development of the basin. The exception is in the extreme south of the basin where the volcanism associated with the Barra Volcanic Ridges combined with indications of relatively strong lithosphere could be evidence of incipient ocean opening.

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Section: Cover Sequence Thicknessmentioning

confidence: 99%

Three-dimensional gravity and magnetic modelling of the Irish sector of the NE Atlantic margin

2010

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“…In terms of its relation to regional fault systems, Williams et al (2005) interpreted the SGCB as a large transtensional basin located at a releasing stepover on a major NW-SE trending Mesozoic-Cenozoic strike-slip fault system comprising the Codling and Sticklepath Faults. Dextral displacements along this fault system also led to the formation of Eocene-Oligocene transtensional basins containing similar deposits in SW England, Central Irish Sea Basin and Northern Ireland (Izatt et al 2001;Cunningham et al 2004;Ziegler 2004). In the southern Irish Sea, the transfer of displacement between the Sticklepath and Codling faults was accommodated by normal movements along the Mochras-St. George's Channel-Bala fault system (Turner 1997;Holford et al 2005b;Williams et al 2005).…”

Section: The Mesozoic-cenozoic Geological Record In the Southern Irismentioning

confidence: 92%

Evidence for kilometre-scale Neogene exhumation driven by compressional deformation in the Irish Sea basin system

Holford

Green²,

Turner

et al. 2008

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“…The forward application in an exhumed basin is illustrated using a regional seismic section across the Central Irish Sea Basin (Izatt, Maingarm and Racey 2001), which has been depth‐converted using velocities from the adjacent 42/8–1 well, to estimate sediment thickness. The Central Irish Sea Basin is a 50 – 70 km wide intra‐continental rift basin, which contains up to 4 km of sediments ranging from Dinantian to Liassic in age, unconformably overlain by up to 350 m of normally‐compacted Quaternary sediments.…”

Section: Applications To Real Datamentioning

confidence: 99%

An algorithm to calculate the gravity anomaly of sedimentary basins with exponential density‐depth relationships

Chappell

Kusznir

2008

Geophysical Prospecting

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A B S T R A C TWe derive wavenumber domain expressions to calculate the gravity anomaly of a body with irregular bounding surfaces and an exponential density-depth relationship. We apply the method to sedimentary basins, which commonly have this type of geometry and density distribution. The mathematical formulation also allows the exponential density-depth relationship to be measured from an arbitrary irregular surface rather than the top surface. Using this arrangement, the gravity anomaly of exhumed sedimentary basins can be predicted if the amount of eroded section can be estimated. The corresponding inverse algorithms are also derived. Examples of the use of the forward algorithms, from the Galicia Interior Basin and the Central Irish Sea Basin, are used to illustrate these methods.

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Fault distribution and timing in the Central Irish Sea Basin

Abstract: Well data analysis and the interpretation of 2D and 3D seismic reflection data provide valuable insights into the distribution and timing of fault activity within the Central

Cited by 5 publications

References 17 publications

Three-dimensional gravity and magnetic modelling of the Irish sector of the NE Atlantic margin

Three-dimensional gravity and magnetic modelling of the Irish sector of the NE Atlantic margin

Evidence for kilometre-scale Neogene exhumation driven by compressional deformation in the Irish Sea basin system

An algorithm to calculate the gravity anomaly of sedimentary basins with exponential density‐depth relationships

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