Crustal structure of the northern Nova Scotia rifted continental margin (eastern Canada)

Funck, Thomas; Jackson, H. R.; Louden, K. E.; Dehler, Sonya A.; Wu, Yue

doi:10.1029/2004jb003008

Cited by 108 publications

(161 citation statements)

References 56 publications

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“…An abrupt transition is not observed on either line, but the rise of the Moho from 26 to 22 km on line P2 and from 27 km (Weber et al, 2004) near Gaza to 22 km on line P1 could mark a zone with a gradual transition from continental to oceanic crust. Such a transition zone has been observed elsewhere, e.g., at the Hatton margin offshore Ireland (Vogt et al, 1998), at the Flemish Cap off New Foundland (Funck et al, 2004) and in Nova Scotia (Funck et al, 2004). In Nova Scotia and at the Flemish Cap ,the transition zones are characterized by an extremely thinned crust of 2-3km overlying serpentinized mantle with 7.2-7.6km/s (Nova Scotia) or 7.7-7.9 km/s (Flemish Cap).…”

Section: Velocity Distribution and Crustal Structurementioning

confidence: 93%

The Levantine Basin—crustal structure and origin

et al. 2006

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The origin of the Levantine Basin in the Southeastern Mediterranean Sea is related to the opening of the Neo-Tethys. The nature of its crust has been debated for decades. Therefore, we conducted a geophysical experiment in the Levantine Basin. We recorded two refraction seismic lines with 19 and 20 ocean bottom hydrophones, respectively, and developed velocity models. Additional seismic reflection data yield structural information about the upper layers in the first few kilometers. The crystalline basement in the Levantine Basin consists of two layers with a P-wave velocity of 6.0-6.4km/s in the upper and 6.5-6.9 km/s in the lower crust. Towards the center of the basin, the Moho depth decreases from 27 to 22km. Local variations of the velocity gradient can be attributed to previously postulated shear zones like the Pelusium Line, the Damietta-Latakia Line and the Baltim-Hecateus Line. Both layers of the crystalline crust are continuous and no indication for a transition from continental to oceanic crust is observed. These results are confirmed by gravity data. Comparison with other seismic refraction studies in prolongation of our profiles under Israel and Jordan and in the Mediterranean Sea near Greece and Sardinia reveal similarities between the crust in the Levantine Basin and thinned continental crust, which is found in that region. The presence of thinned continental crust under the Levantine Basin is therefore suggested. A β-factor of 2.3-3 is estimated. Based on these findings, we conclude that sea-floor spreading in the Eastern Mediterranean Sea only occurred north of the Eratosthenes Seamount, and the oceanic crust was later subducted at the Cyprus Arc.

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Section: Velocity Distribution and Crustal Structurementioning

confidence: 93%

The Levantine Basin—crustal structure and origin

et al. 2006

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“…An example of such a margin is the eastern Nova Scotia margin sampled by profile SMART1 (Fig. 1) [35]. Here, velocities of >7.0 km/s are reached only ~2 km beneath top basement and the adjacent oceanic crust is not unusually thick, but normal mantle velocities are not reached until 7-8 km beneath top basement.…”

Section: P-wave Velocity Structurementioning

confidence: 99%

Geophysical characterisation of the ocean–continent transition at magma-poor rifted margins

Minshull

2008

Comptes Rendus. Géoscience

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Geophysical characterisation of the ocean-continent transition (OCT) at magma-poor rifted margins has focused primarily on the determination of P wave velocities using wide-angle seismic techniques. Such experiments have shown that the OCT is heterogeneous, but that typically velocities increase gradually with depth from ~5.0 km/s at top basement to ~8.0 km/s at ~5 km deeper, without a large and abrupt Moho transition. The velocity variation with depth is similar to that of old fracture zone crust, and appears to differ from that of oceanic crust formed at ultra-slow spreading rates, though sampling of the latter is limited.Typically, the OCT is characterised by weakly lineated, low amplitude magnetic anomalies; the interpretation of these anomalies remains controversial. The oceanward limit of the OCT remains poorly defined on many margins.

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“…To first order, the large-scale synrift geometry of a rifted margin will depend on the distribution of lithospheric extension across the margin. In designing the models we assume that (1) lithospheric extension is uniform with depth, (2) the extension varies across the 200 km margin in an approximately linear manner that is consistent with crustal models developed by Keen and Potter [1995], Funck et al [2004], and Wu et al [2006], and (3) the stretched margin is in isostatic equilibrium in a configuration determined by the thickness, density and thermal state of the extended lithosphere. Synrift salt and clastic sediments load the margin and the system is flexurally isostatically balanced in a submarine configuration including loading by the water.…”

Section: Initial Configuration Of the Model Continental Margin And Samentioning

confidence: 99%

“…We chose h cc = 35 km, h oc = 6.5 km, and densities r cc = r oc = 2860 kg m −3 , and r cm = r om = 3225 kg m −3 , which allows the depth of the top of the oceanic crust to be calculated. Corresponding depths across the margin, assumed to be 200 km wide between positions X 1 and X 2 (a geometry consistent with recent seismic refraction surveys [Keen and Potter, 1995;Funck et al, 2004;Wu et al, 2006]), are calculated by linear interpolation because the lithosphere is assumed to thin linearly across the margin.…”

Section: Appendix B: Parameterized Model For Lithospheric Isostasy Anmentioning

confidence: 99%

An investigation of salt tectonic structural styles in the Scotian Basin, offshore Atlantic Canada: 1. Comparison of observations with geometrically simple numerical models

Albertz¹,

Beaumont

Shimeld

et al. 2010

Tectonics

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[1] Three primary salt tectonic structural styles of the Scotian Basin are compared with plane strain finite element models in order to investigate their origin. Here, we focus on simplified model salt basins with initial rectangular cross-sectional geometries and follow their evolution in the context of tectonic and parametric thermal subsidence and under various sedimentation regimes. Structural style A, an open-ended roho system with a synkinematic wedge, is reproduced by models including deltaic progradation and seaward spreading/ gliding of sediments above a salt detachment. Structural style B, a linked salt tectonic system with landward regional normal faults and allochthonous salt sheets climbing seaward over Late Cretaceous and Paleogene strata, is shown to be a consequence of early aggradation followed by progradation. Structural style C is characterized by salt diapirs and intervening minibasins and is reproduced by models with Rayleigh-Taylor instabilities requiring compaction driven density inversions, weak sediments, and initial perturbations of the overburden-salt interface.

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Crustal structure of the northern Nova Scotia rifted continental margin (eastern Canada)

Cited by 108 publications

References 56 publications

The Levantine Basin—crustal structure and origin

The Levantine Basin—crustal structure and origin

Geophysical characterisation of the ocean–continent transition at magma-poor rifted margins

An investigation of salt tectonic structural styles in the Scotian Basin, offshore Atlantic Canada: 1. Comparison of observations with geometrically simple numerical models

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