Deep structure of the Mid-Norwegian shelf and onshore-offshore correlations: Insight from potential field data

Skilbrei, Jan Reidar; Olesen, Odleiv

doi:10.1016/s0928-8937(05)80043-8

Cited by 10 publications

(17 citation statements)

References 25 publications

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“…There is currently little consensus concerning the possible duration and extent of Permo‐Triassic rifting in the Åsgard area in particular, or on the Halten Terrace in general. Firstly, several previous studies have argued that the distribution of these earlier extensional structures controls the geometry and location of Jurassic faults (Doré et al , 1997; Brekke, 2000; Osmundsen et al , 2002; Skilbrei & Olesen, 2005). Secondly, the Late Permian–Early Triassic rift topography is thought to have been one of the main controls on the thickness of Middle to Upper Triassic evaporites (Müller et al , 2005; Richardson et al , 2005).…”

Section: Results: Fault Growth and Evolutionmentioning

confidence: 99%

The structural evolution of the Halten Terrace, offshore Mid‐Norway: extensional fault growth and strain localisation in a multi‐layer brittle–ductile system

et al. 2010

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Tectonic subsidence in rift basins is often characterised by an initial period of slow subsidence (‘rift initiation’) followed by a period of more rapid subsidence (‘rift climax’). Previous work shows that the transition from rift initiation to rift climax can be explained by interactions between the stress fields of growing faults. Despite the prevalence of evaporites throughout the geological record, and the likelihood that the presence of a regionally extensive evaporite layer will introduce an important, sub‐horizontal rheological heterogeneity into the upper crust, there have been few studies that document the impact of salt on the localisation of extensional strain in rift basins. Here, we use well‐calibrated three‐dimensional seismic reflection data to constrain the distribution and timing of fault activity during Early Jurassic–Earliest Cretaceous rifting in the Åsgard area, Halten Terrace, offshore Mid‐Norway. Permo‐Triassic basement rocks are overlain by a thick sequence of interbedded halite, anhydrite and mudstone. Our results show that rift initiation during the Early Jurassic was characterised by distributed deformation along blind faults within the basement, and by localised deformation along the major Smørbukk and Trestakk faults within the cover. Rift climax and the end of rifting showed continued deformation along the Smørbukk and Trestakk faults, together with initiation of new extensional faults oblique to the main basement trends. We propose that these new faults developed in response to salt movement and/or gravity sliding on the evaporite layer above the tilted basement fault blocks. Rapid strain localisation within the post‐salt cover sequence at the onset of rifting is consistent with previous experimental studies that show strain localisation is favoured by the presence of a weak viscous substrate beneath a brittle overburden.

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Section: Results: Fault Growth and Evolutionmentioning

confidence: 99%

The structural evolution of the Halten Terrace, offshore Mid‐Norway: extensional fault growth and strain localisation in a multi‐layer brittle–ductile system

et al. 2010

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“…As a strong magnetic contrast often exists between the sediments and the underlying crystalline basement the magnetic data can be used to estimate depth to the basement. This method has previously been used effectively on the mid‐Norwegian margin (Åm 1970; Skilbrei and Olesen 2005). Skilbrei and Olesen (2005) studied the accuracy and the geological meaning of the ‘magnetic basement’ on the mid‐Norwegian margin.…”

Section: Methodsmentioning

confidence: 99%

“…This method has previously been used effectively on the mid‐Norwegian margin (Åm 1970; Skilbrei and Olesen 2005). Skilbrei and Olesen (2005) studied the accuracy and the geological meaning of the ‘magnetic basement’ on the mid‐Norwegian margin. They found generally good agreement between estimates made from magnetic anomalies and the depth to the Precambrian basement.…”

Section: Methodsmentioning

confidence: 99%

The use of potential field data in revealing the basement structure in sub‐basaltic settings: an example from the Møre margin, offshore Norway

Reynisson

Ebbing

Skilbrei

2009

Geophysical Prospecting

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This study investigates the utility of the potential fields (gravity and magnetics) in volcanic settings as observed on the Møre margin. Synthetic models are used to investigate the effect of volcanics on the gravity and magnetic fields. The focus is on detecting sub‐basaltic basement structures. The methods applied to the models are Euler deconvolution on magnetic data, gravity gradients and integrated 3D gravity and magnetic forward modelling. The same methods are used on the Møre margin and the results compared to the synthetic models. The Euler deconvolution on the magnetic signal does provide limited depth solutions in the volcanic environment and the use of different observation levels does not enhance the results. Forward gravity and magnetic models provide a valuable tool to estimate both the basalt and sub‐basaltic sedimentary thickness but are limited by the ambiguity inherent in potential field methods. The use of gravity gradients significantly decreases the available model solutions and provides boundary detection even in sub‐basaltic settings.

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“…The margin comprises three main segments, the Trøndelag Platform, the Vøring Basin and the Vøring Marginal High; which are separated by N‐S and NE‐SW‐trending fault systems (Blystad et al 1995). Seismic studies and potential field studies have shown that the basins underlying the margin have a thickness up to 15 km (e.g., Brekke 2000; Skilbrei and Olesen 2005; Mjelde et al 2005).…”

Section: Introductionmentioning

confidence: 99%

“…Potential field studies constrained by seismic profiles can help to identify the 3D structure of the basement underlying sedimentary basins (e.g., Skilbrei and Olesen 2005; Ebbing et al 2006), which is important for models of basin evolution. Using common interpretation techniques, gravity and magnetic data can be used to constrain the top basement as well as the base of the crust (Moho) and to identify different intra‐basement domains, if they are expressed by changes in petrophysical properties.…”

Section: Introductionmentioning

confidence: 99%

A discussion of structural and thermal control of magnetic anomalies on the mid‐Norwegian margin

Ebbing¹,

Gernigon²,

Pascal³

et al. 2009

Geophysical Prospecting

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A B S T R A C TWe discuss the correlation between the depth extent of magnetic sources, the Curie temperature depth and crustal structures on the mid-Norwegian margin. Spectral methods can be used to estimate the depth extent of magnetic sources, even if the bottom is located in the lower crust, however, only with limited resolution. The bottom of the magnetic surfaces is often regarded to represent the depth to the Curie isotherm. However, comparison with a 3D model based on the interpretation of potential field and seismic reflection data and thermal modelling shows that the depth extent of the magnetic sources is merely controlled by the overall geometry of the crystalline crust and not the temperature distribution. The observed changes in the magnetic field between the inner and outer part of the mid-Norwegian margin appears not to reflect, as previously assumed, the depth to the Curie temperature but the geometry of the basement and lower crust. Our 3D model of the mid-Norwegian margin reveals a basement configuration that involves a basement with different petrophysical properties, which can be connected with lithological basement units of onshore Norway.

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Deep structure of the Mid-Norwegian shelf and onshore-offshore correlations: Insight from potential field data

Cited by 10 publications

References 25 publications

The structural evolution of the Halten Terrace, offshore Mid‐Norway: extensional fault growth and strain localisation in a multi‐layer brittle–ductile system

The structural evolution of the Halten Terrace, offshore Mid‐Norway: extensional fault growth and strain localisation in a multi‐layer brittle–ductile system

The use of potential field data in revealing the basement structure in sub‐basaltic settings: an example from the Møre margin, offshore Norway

A discussion of structural and thermal control of magnetic anomalies on the mid‐Norwegian margin

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