Sveconorwegian igneous complexes beneath the Norwegian–Danish Basin

Olesen, Odleiv; Smethurst, M. A.; Torsvik, Trond H.; Bidstrup, Torben

doi:10.1016/j.tecto.2004.06.009

Cited by 32 publications

(22 citation statements)

References 52 publications

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“…2), our model area is bounded by the Sorgenfrei-Tornquist and the Lithosphere Transition zones which separate lithospheric blocks with different thicknesses and velocities (Berthelsen, 1992;Thybo, 2001;Cotte et al, 2002;Gregersen et al, 2005;Shomali et al, 2006;Medhus et al, 2009Medhus et al, , 2012Hejrani et al, 2015Hejrani et al, , 2017Kolstrup et al, 2015;Köhler et al, 2015). These deeply seated, lithosphere-scale, fault zones may possibly represent Precambrian suture zones (Olesen et al, 2004), Maystrenko et al, 2012. Faults are after Sigmond (2002) and LTZ is after Medhus et al (2012).…”

Section: Tectonic Settingsmentioning

confidence: 99%

“…The uppermost crystalline layer comprises gabbro to anorthositic rocks Olesen et al (2004) ratio of remanent to induced magnetisation) to some rocks in order to fit the observed and modelled magnetic anomalies (Table 4). Measured values of remanent declination and remanent inclination have been used for the SE middle-upper crustal intrusion and the upper-crustal magmatic rocks of the Rogaland Igneous Province based on the values published by McEnroe et al (1996), Brown & McEnroe (2004) and Olesen et al (2004). Consequently, remanent declination and inclination have been set to be 293° and -64°,respectively, for the rocks of the Rogaland Igneous Province and two Q-values of 3 and 7 have been chosen for these rocks.…”

Section: Densities and Magnetic Propertiesmentioning

confidence: 99%

“…Brown & McEnroe (2004 have also shown that parameters of the paleomagnetic field (declination and inclination) within the Rogaland Igneous Province can also vary quite strongly locally and, therefore, our chosen values are indicative numbers rather than the real ones. In addition, different values of remanent declination and inclination of the SE middle-upper crustal magmatic intrusion have been tested during the modelling based on the data published by Torsvik et al (1997) and Olesen et al (2004) with the preferable one according to Torsvik et al (1997) (Table 4). Moreover, remanent declination and inclination have been used for the Jotun Nappe Complex according to measured values published by Piper & Poppleton (1990).…”

Section: Densities and Magnetic Propertiesmentioning

confidence: 99%

“…Our knowledge of the structure of the crystalline crust within the study area is mainly based on 2D deep reflection and refraction seismic lines (Calcagnile, 1982;Christie, 1982;Barton & Wood, 1984;Klemperer & White, 1989;Iwasaki et al, 1994;McBride & England, 1999;Abramovitz & Thybo, 2000;Christiansson et al, 2000;Nielsen et al, 2000;Erickson, 2004;Sandrin & Thybo, 2008;Sandrin et al, 2009;Stratford et al, 2009;Stratford & Thybo, 2011;Thybo & Nielsen, 2012;Kvarven et al, 2014Kvarven et al, , 2016 and teleseismic receiver functions (Ottemöller & Midzi, 2003;Svenningsen et al, 2007). Furthermore, several potential field studies have revealed additional important features of the deep structure within the study area both in 2D (Åm, 1973;Hovland, 1987;Olesen et al, 2004;Lyngsie et al, 2006;Fichler et al, 2011;Ebbing et al, 2012;Kvarven et al, 2014;Nirrengarten et al, 2014 and others) and in 3D (Tesauro et al, 2007;Yegorova et al, 2007;Kaban et al, 2010;). …”

Section: Introductionmentioning

confidence: 99%

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Deep structure of the northern North Sea and southwestern Norway based on 3D density and magnetic modelling

Maystrenko¹,

Olesen²,

Ebbing³

et al. 2017

NJG

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The deep structure of the northern North Sea and the adjacent Norwegian mainland has been analysed by integrating all available structural data in combination with 3D density and magnetic modelling into a lithosphere-scale 3D structural model. The modelled configurations of the sedimentary cover and crystalline crust are consistent with the long-wavelength components of the observed gravity and magnetic fields over the study area. The first-order configurations of the top of the crystalline basement and the Moho topography have been obtained. According to the 3D density modelling, the low-density upper-crustal block beneath the Horda Platform has been shown to indicate a possible presence of metasedimentary and/or fractured granitic rocks. Possible remnants of island arc chains within the central part of the North Sea between the Laurentian and Baltican crustal domains are supported by the modelling. Moreover, based on the results of the 3D magnetic modelling, the 3D density/structural model has been differentiated into smaller crustal blocks with different magnetic properties, implying that these magnetically derived crustal blocks most likely differ lithologically from the rest of the initial density-based larger layers. Within the mainland, most of the crustal blocks with increased magnetic susceptibility are related to granitic and/or granodioritic rocks which are well mapped at the surface according to geological data. A prominent middle-upper crustal magmatic intrusion has been modelled within the northern part of the NorwegianDanish Basin. The local magnetic pattern supports a possible Permian age for this intrusion, whereas the regional magnetic pattern and known geology from the mainland indicate a Sveconorwegian origin as a more viable alternative. At the mantle level, a low-density lithospheric mantle has been modelled beneath NW Norway and adjacent offshore areas, reflecting the likely presence of an upper-mantle low-velocity zone there.

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Section: Tectonic Settingsmentioning

confidence: 99%

Section: Densities and Magnetic Propertiesmentioning

confidence: 99%

Section: Densities and Magnetic Propertiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Deep structure of the northern North Sea and southwestern Norway based on 3D density and magnetic modelling

Maystrenko¹,

Olesen²,

Ebbing³

et al. 2017

NJG

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“…Potential field studies and particularly high-resolution aeromagnetic data have long been known and employed to complement field investigations and mapping, notably in poorly exposed regions and also on continental shelves in different parts of the world (e.g., Åm, 1973;Mettone et al, 1987;Nielsen, 1987;Vasilieva & FrankKamenetsky, 2003;Olesen et al, 2004;Genske et al, 2012). Where not exposed on the present-day surface, plutons, dyke swarms and even ore deposits identified by geophysical methods are commonly referred to as 'blind' features (e.g., Genske et al, 2012), in much the same sense as structural geologists refer to blind thrusts, meaning that these particular faults remain concealed, at varying depths, having not managed to propagate to the terrain surface.…”

Section: Discussionmentioning

confidence: 99%

Multiphase mafic dykes in the Caledonides of northern Finnmark revealed by a new high-resolution aeromagnetic dataset

Nasuti¹,

Roberts²,

Gernigon³

2015

NJG

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New high-resolution aeromagnetic data from northern Finnmark provide confirmatory evidence for the existence of both metadolerite and unmetamorphosed dolerite dykes transecting the Caledonian nappes and subjacent (par)autochthonous lithostratigraphical successions from Magerøya in the west to Varanger Peninsula in the east. Three ages of mafic dykes are known from isotopic dating studies -Ediacaran, Late Devonian and Early Carboniferous -but actual dyke outcrop in the case of the two younger dyke sets is very limited. High-amplitude magnetic responses in two thrust sheets in northwestern Varanger Peninsula, north of the TKFZ and beneath the Tanahorn Nappe, are clearly shown to relate to swarms of Ediacaran metadolerite dykes. Individual dykes discontinuously exposed on the surface can be followed as linear positive magnetic anomalies over distances of 25 km inland. Their extent offshore is not discussed here because it is beyond our data coverage in this paper. In eastern Varanger Peninsula, 8-9 dolerite dykes of Late Devonian age occur in discontinuous or limited outcrop. The new aeromagnetic data show, however, that up to 20 such dykes can be identified in the subsurface in the region between Vardø and Syltefjorden based on their linear positive magnetic anomaly signatures. South of the TKFZ, two Late Devonian dolerite dykes, well known from small coastal outcrops, are clearly visible as linear positive magnetic anomalies both on land and offshore beneath the sea-floor of Varangerfjorden. The most spectacular manifestations of what we consider to represent blind dolerite dykes are seen in connection with linear positive magnetic anomalies relating to Early Carboniferous dolerite dykes exposed on Magerøya and western Digermul Peninsula. These prominent linear anomalies follow many of the mapped NW-SE-to WNW-ESE-trending faults that have disrupted the Caledonian nappes in this part of Finnmark, and some are continuous over distances of more than 100 km from Magerøya to western Varanger Peninsula. These particular dykes and faults have been interpreted as relating to a major period of extension and rifting that occurred in the SW Barents Sea and adjacent onshore areas of Norway in Carboniferous time.

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