Crustal structure beneath Orphan Basin and implications for nonvolcanic continental rifting

Chian, D.; Reid, I.; Jackson, H. R.

doi:10.1029/2000jb900422

Cited by 51 publications

(80 citation statements)

References 52 publications

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“…This gravity high zone, which runs from NW of Flemish Cap to the Charlie-Gibbs Fracture Zone, is also significantly wider than would typically be expected for a rifted margin and may correspond to an interpreted failed rift zone where higher density mantle material lies closer to the surface (Chian et al 2001). The overall gravity low in the Orphan Basin near the White Sail Fault suggests sagging in the centre of the basin, possibly owing to a weak upper mantle.…”

Section: Inversion Resultsmentioning

confidence: 95%

“…Significantly, the highly thinned crust immediately outboard of the Bonavista Platform on transect A-A′ (Fig. 6) has also been detected from seismic refraction modelling studies (Chian et al 2001), where it was interpreted as the product of the development of a failed rift.…”

Section: Conjugate Margin Comparisonsmentioning

confidence: 88%

“…Profile 84-3 transects the Orphan Basin and extends SW-NE from the Bonavista Platform of the Grand Banks, across the Orphan Basin to beyond Orphan Knoll, an isolated continental fragment lying inboard of the continent-ocean boundary (Keen et al 1987b;Keen & de Voogd 1988). Coincident wide-angle seismic reflection/ refraction modelling along this profile has revealed that the Orphan Basin is underlain by stretched continental crust extending more than 400 km to Orphan Knoll (Chian et al 2001). …”

Section: The Northeastern Flemish Cap and Orphan Basin Marginsmentioning

confidence: 95%

“…In contrast, inferred middle crustal densities thin out near magnetic chron 34. It is interesting to note that the inferred failed rift identified along transect A-A′ (Chian et al 2001) appears wider and less obvious in terms of crustal thickness along transect B-B′.…”

Section: Conjugate Margin Comparisonsmentioning

confidence: 96%

“…6) crosses from the Bonavista Platform, through the West Orphan Basin and Orphan Knoll (a foundered continental fragment (Keen et al 1987b;Chian et al 2001)), across the Porcupine Bank and onto the Irish Mainland Platform. This transect reveals the significant difference in relatively undeformed crustal thickness between the Bonavista Platform, where it exceeds 35 km, and both the Porcupine Bank and the Irish Mainland Platform, which are closer to the regional average of 30 km for unstretched crust onshore in Ireland (Lowe & Jacob 1989).…”

Section: Conjugate Margin Comparisonsmentioning

confidence: 99%

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Comparison of lithosphere structure across the Orphan Basin–Flemish Cap and Irish Atlantic conjugate continental margins from constrained 3D gravity inversions

Welford

Shannon

O’Reilly

et al. 2012

JGS

127

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Regionally constrained 3D gravity inversion results on the Orphan Basin-Flemish Cap and the Irish Atlantic conjugate continental margins are compared to investigate crustal structure, early rifting history and geological evolution of this part of the North Atlantic. The full-crustal density anomaly distributions provide some of the first depth images of how rifted structures compare along and across these conjugate margins. Broad similarities in crustal structure are identified with some noticeable differences, linked to rifting and crustal stretching processes. Extreme crustal thinning (stretching factors >3.5) is indicated beneath much of the southern Porcupine Basin, the western half of West Orphan Basin, the eastern half of Jeanne d'Arc Basin, the southeastern half of East Orphan Basin and in pockets beneath Rockall Basin. This appears to have resulted in the serpentinization (and possible exhumation) of mantle lithosphere on the Irish Atlantic and Flemish Cap margins but not beneath Orphan Basin. A simple evolution model is proposed for the early stages of rifting between the margins. It is suggested that ancient orogenic sutures played an important role in controlling the northward migration of rifting and the rotation and displacement of Flemish Cap out of Orphan Basin.Supplementary material: Enlarged maps from this paper are available at www.geolsoc.org.uk/SUP18527.

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Section: Inversion Resultsmentioning

confidence: 95%

Section: Conjugate Margin Comparisonsmentioning

confidence: 88%

Section: The Northeastern Flemish Cap and Orphan Basin Marginsmentioning

confidence: 95%

Section: Conjugate Margin Comparisonsmentioning

confidence: 96%

Section: Conjugate Margin Comparisonsmentioning

confidence: 99%

See 3 more Smart Citations

Comparison of lithosphere structure across the Orphan Basin–Flemish Cap and Irish Atlantic conjugate continental margins from constrained 3D gravity inversions

Welford

Shannon

O’Reilly

et al. 2012

JGS

127

View full text Add to dashboard Cite

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Crustal and basin evolution of the southwestern Barents Sea: From Caledonian orogeny to continental breakup

et al. 2014

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A new generation of aeromagnetic data documents the post-Caledonide rift evolution of the southwestern Barents Sea (SWBS) from the Norwegian mainland up to the continent-ocean transition. We propose a geological and tectonic scenario of the SWBS in which the Caledonian nappes and thrust sheets, well-constrained onshore, swing from a NE-SW trend onshore Norway to NW-SE/NNW-SSE across the SWBS platform area. On the Finnmark and Bjarmeland platforms, the dominant inherited magnetic basement pattern may also reflect the regional and post-Caledonian development of the late Paleozoic basins. Farther west, the pre-breakup rift system is characterized by the Loppa and Stappen Highs, which are interpreted as a series of rigid continental blocks (ribbons) poorly thinned as compared to the adjacent grabens and sag basins. As part of the complex western rift system, the Bjørnøya Basin is interpreted as a propagating system of highly thinned crust, which aborted in late Mesozoic time. This thick Cretaceous sag basin is underlain by a deep-seated high-density body, interpreted as exhumed high-grade metamorphic lower crust. The abortion of this propagating basin coincides with a migration and complete reorganization of the crustal extension toward a second necking zone defined at the level of the western volcanic sheared margin and proto-breakup axis. The abortion of the Bjørnøya Basin may be partly explained by its trend oblique to the regional, inherited, structural grain, revealed by the new aeromagnetic compilation, and by the onset of further weakening later sustained by the onset of magmatism to the west.

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A volcanic province near the western termination of the Charlie-Gibbs Fracture Zone at the rifted margin, offshore northeast Newfoundland

2014

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Crustal structure beneath Orphan Basin and implications for nonvolcanic continental rifting

Cited by 51 publications

References 52 publications

Comparison of lithosphere structure across the Orphan Basin–Flemish Cap and Irish Atlantic conjugate continental margins from constrained 3D gravity inversions

Comparison of lithosphere structure across the Orphan Basin–Flemish Cap and Irish Atlantic conjugate continental margins from constrained 3D gravity inversions

Crustal and basin evolution of the southwestern Barents Sea: From Caledonian orogeny to continental breakup

A volcanic province near the western termination of the Charlie-Gibbs Fracture Zone at the rifted margin, offshore northeast Newfoundland

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