Crustal structure of the Lofoten–Vesterålen continental margin, off Norway

Tsikalas, Filippos; Eldholm, Olav; Faleide, Jan Inge

doi:10.1016/j.tecto.2005.04.002

Cited by 74 publications

(86 citation statements)

References 56 publications

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“…In the Faeroe-Shetland Basin, the Late Paleocene-Early Eocene phase coincides with a strong unconformity and prograding sands and mudstone sequences offshore Faeroes (Sørensen et al, 2003). Along the Northeast Greenland shelf, five sequences of eastward prograding wedges document a strong uplift of the Greenlandic mainland from Paleocene to Early Eocene time (Tsikalas et al, 2005). Fig.…”

Section: Uplift History Of the Marginsmentioning

confidence: 91%

“…1), the initial oceanic crust is ~12 -15 km thick (Tsikalas et al, 2005). A LCB is documented seaward of the shelf edge.…”

Section: Volume Of Magmatismmentioning

confidence: 96%

“…The thickness of the LCB not only varies laterally (Tsikalas et al, 2005;Ebbing et al, 2006), but there is also discussion regarding its magmatic nature (Ebbing et al, 2006;Gernigon et al, 2006). A widely accepted interpretation of these bodies is magmatic underplating, representing both ponded magmatic material trapped beneath the Moho and magmatic sills injected into the lower crust (Furlong and Fountain, 1986;White and McKenzie, 1989).…”

Section: Volume Of Magmatismmentioning

confidence: 99%

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The North Atlantic Igneous Province: A review of models for its formation

Meyer

Wijk²,

Gernigon³

2007

Special Paper 430: Plates, Plumes and Planetary Processes

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The mantle plume concept is currently being challenged as an explanation for North Atlantic Igneous Province formation. Alternative models have been suggested, including delamination, meteorite impact, small-scale rift-related convection, and chemical mantle heterogeneities. We review available datasets on uplift, strain localization, age and chemistry of igneous material, and tomography for the North Atlantic Igneous Province, and compare them with predictions from the mantle plume and alternative models. The mantle plume concept is quite successful in explaining formation of the NAIP, but unexplained aspects remain. Delamination and impact models are currently not supported. Rift-related small-scale convection models appear to be able to explain volcanic rifted margin volcanism well. However, the most important problem that non-plume models need to overcome is the continuing, long-lived melt anomaly extending via the Greenland-Faeroe Ridges to Iceland. Mantle heterogeneities, resulting from an ancient subducted slab, are included in plate tectonic models to explain the continuing melt production as an alternative to the mantle plume model, but there are still uncertainties related to this idea that need to be solved.

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Section: Uplift History Of the Marginsmentioning

confidence: 91%

“…1), the initial oceanic crust is ~12 -15 km thick (Tsikalas et al, 2005). A LCB is documented seaward of the shelf edge.…”

Section: Volume Of Magmatismmentioning

confidence: 96%

Section: Volume Of Magmatismmentioning

confidence: 99%

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The North Atlantic Igneous Province: A review of models for its formation

Meyer

Wijk²,

Gernigon³

2007

Special Paper 430: Plates, Plumes and Planetary Processes

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“…Such elongate "edge effect" positive gravity anomalies are considered commonly observed features at passive continental margins [Rabinowitz and LaBrecque, 1979;Watts and Fairhead, 1999]; however, due to the inherent ambiguity in potential field interpretations, the genetic cause of these anomalies is not always clear. In particular, their cause has been ascribed in many margins to the difference in depth to major lateral, near-seafloor density contrasts and the equivalent depth difference of base crust compensation [e.g., Talwani and Eldholm, 1972;Tsikalas et al, 2005]. These "edge effect" positive gravity anomalies have also been interpreted as caused by the juxtaposition of continental and oceanic crust [Rabinowitz and LaBrecque, 1979;Bauer et al, 2000], as well as due to magmatic underplating [e.g., Watts, 2001].…”

Section: Margin Settingmentioning

confidence: 99%

“…This model predicts the occurrence of crustal-scale shear zones that are able to thin the crust to less than 10 km, without the presence of distributed normal faulting in the upper crust [Lavier and Manatschal, 2006]. At the same time, even minor shallowing of the Moho may lead to decompressional melts that are accreted on to the lower crust thereby increasing its density [e.g., Tsikalas et al, 2005]. Consequently thermal subsidence will enhance the accumulation of relatively thick and tectonically undeformed "sag" basins (Figures 15a and 15b) [e.g., Huismans and Beaumont, 2008].…”

Section: Total Rift Evolutionmentioning

confidence: 99%

Crustal breakup and continent-ocean transition at South Atlantic conjugate margins

Blaich¹,

Faleide²,

Tsikalas³

2011

J. Geophys. Res.

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146

174

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[1] Seismic reflection and refraction profiles, and potential field data, complemented by crustal-scale gravity modeling and plate reconstructions are used to study the evolution of the central and south segments of the South Atlantic conjugate margins. The central segment is characterized by a hyperextended continent-ocean transitional domain that shows evidence of rotated fault blocks and a detachment surface active during rifting. A polyphase rifting evolution mode, associated with a complex time-dependent thermal structure of the lithosphere, is substantiated for the central segment that is not a "magma-poor" end-member. Increase of volcanic activity during the late stages of rifting may have "interrupted" the extensional system implying a failed exhumation phase that was replaced instead by continental breakup and emplacement of fully igneous crust. The continent-ocean transitional domain along the "magma-dominated" south segment is characterized by a large volume of flood basalts and high-velocity/high-density lower crust. The northern province of the south segment is characterized by symmetrical seaward-dipping reflections and symmetrical continent-ocean transitional domain. The influence of the Tristan da Cunha plume on this province is very likely. The central province of the south segment is characterized by along-strike tectonomagmatic asymmetry, which can be caused by the initial continental stretching and accompanying magmatism rather than by the subsequent seafloor spreading. The Tristan da Cunha plume on the central province may have influenced the volume of magmatism but did not necessarily alter the process of rifted margin formation, implying that the central province of the south segment may have much in common with "magma-poor" margins.

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Accurate measurements of residual topography from the oceanic realm

2014

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In the oceans, our understanding of plate subsidence as a function of age permits residual depth anomalies to be identified and mapped. These anomalies may reflect dynamic topography and could be an important means for constraining convective circulation of the sublithospheric mantle. Here we analyze a global database of seismic reflection and wide‐angle profiles from heavily sedimented oceanic crust, which abuts continental lithosphere. At 449 locations, we calculated water‐loaded subsidence, compared it with a reference age‐depth relationship, and determined residual depth. We then combined these spot measurements of residual depth with observations from mid‐oceanic ridges and from selected ship track bathymetry to construct a global map of residual depth. Our results suggest that the amplitude of residual depth varies by up to ±1 km with wavelengths of order 103 km. We compare our residual depths with free‐air gravity and seismic tomographic anomalies. Our results show that residual depths correlate with long‐wavelength gravity anomalies. In contrast, correlations between residual depths and vertically averaged shear velocity anomalies within the upper and/or the lower mantle are weaker. The largest discrepancies occur at short (∼1000 km) wavelengths. These combined observations suggest that residual depth anomalies could be generate by density variations within a thin (∼102 km) low‐viscosity layer beneath the lithosphere. Our global compilation should play a significant role in helping to refine predictive geodynamical models.

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Crustal structure of the Lofoten–Vesterålen continental margin, off Norway

Cited by 74 publications

References 56 publications

The North Atlantic Igneous Province: A review of models for its formation

The North Atlantic Igneous Province: A review of models for its formation

Crustal breakup and continent-ocean transition at South Atlantic conjugate margins

Accurate measurements of residual topography from the oceanic realm

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