An integrated geophysical study of Vestbakken Volcanic Province, western Barents Sea continental margin, and adjacent oceanic crust

Libak, Audun; Mjelde, Rolf; Keers, Henk; Faleide, Jan Inge; Murai, Yoshio

doi:10.1007/s11001-012-9155-3

Cited by 19 publications

(14 citation statements)

References 57 publications

(92 reference statements)

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“…Of particular interest here would be a conjugate to the Vestbakken Volcanic Province that is characterized by volcanic rocks and a HVLC (Fig. 7c) (Libak et al 2012). Conjugate to this province, seismic reflection data show some strong, but discontinuous, reflectors that might be SDRs (cf.…”

Section: Discussionmentioning

confidence: 99%

“…The oceanic crust along this profile has a general thickness of 7 km, with variations of between 5 and 9 km. Velocities in the interpreted oceanic layer 3 (6.8-7.7 km s 21 ) are rather high and could also be compatible with partially serpentinized mantle, a possibility that was not ruled out by Libak et al (2012). In this case, the thickness of the oceanic crust would be overestimated.…”

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confidence: 88%

“…The oceanic crust lacks The rifted Vestbakken margin segment is illustrated by line 1 of the OBS 2008 experiment (Fig. 7c) (Libak et al 2012). In contrast to the rapid crustal thinning observed at the Hornsund margin, the shallowing of the Moho is more gradual from a depth of 28 to 13 km over a 170 km-wide zone.…”

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confidence: 94%

“…In contrast to the rapid crustal thinning observed at the Hornsund margin, the shallowing of the Moho is more gradual from a depth of 28 to 13 km over a 170 km-wide zone. Landward of the COB, increased velocities of up to 7.5 km s 21 are observed in the lower crust, which are interpreted as intrusions (Libak et al 2012). Within the region of the HVLC, volcanoes are observed (their position is indicated in Fig.…”

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confidence: 97%

“…Within the region of the HVLC, volcanoes are observed (their position is indicated in Fig. 7c) and Libak et al (2012) interpreted the upwarping of velocity contours in the lowermost sedimentary layer (velocities of 4.4-5.2 km s 21 ) as marking feeder dykes. Prominent volcanoes, as well as sill intrusions, are interpreted in seismic reflection data at the outer margin at the Vestbakken Volcanic Province with two phases of volcanism in the early Eocene and early Oligocene (Faleide et al 1988).…”

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confidence: 97%

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A review of the NE Atlantic conjugate margins based on seismic refraction data

Funck

Gaina

Geissler

et al. 2016

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The NE Atlantic region evolved through several rift episodes, leading to break-up in the Eocene that was associated with voluminous magmatism along the conjugate margins of East Greenland and NW Europe. Existing seismic refraction data provide good constraints on the overall tectonic development of the margins, despite data gaps at the NE Greenland shear margin and the southern Jan Mayen microcontinent. The maximum thickness of the initial oceanic crust is 40 km at the Greenland-Iceland-Faroe Ridge, but decreases with increasing distance to the Iceland plume. High-velocity lower crust interpreted as magmatic underplating or sill intrusions is observed along most margins but disappears north of the East Greenland Ridge and the Lofoten margin, with the exception of the Vestbakken Volcanic Province at the SW Barents Sea margin. South of the narrow Lofoten margin, the European side is characterized by wide margins. The opposite trend is seen in Greenland, with a wide margin in the NE and narrow margins elsewhere. The thin crust beneath the basins is generally underlain by rocks with velocities of .7 km s 21 interpreted as serpentinized mantle in the Porcupine and southern Rockall basins; while off Norway, alternative interpretations such as eclogite bodies and underplating are also discussed.Gold Open Access: This article is published under the terms of the CC-BY 3.0 license.

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Section: Discussionmentioning

confidence: 99%

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confidence: 88%

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confidence: 94%

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confidence: 97%

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confidence: 97%

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A review of the NE Atlantic conjugate margins based on seismic refraction data

Funck

Gaina

Geissler

et al. 2016

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Structure of the oceanic lithosphere and upper mantle north of the Gloria Fault in the eastern mid‐Atlantic by receiver function analysis

2017

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Receiver functions (RF) have been used for several decades to study structures beneath seismic stations. Although most available stations are deployed on shore, the number of ocean bottom station (OBS) experiments has increased in recent years. Almost all OBSs have to deal with higher noise levels and a limited deployment time (∼1 year), resulting in a small number of usable records of teleseismic earthquakes. Here we use OBSs deployed as midaperture array in the deep ocean (4.5–5.5 km water depth) of the eastern mid‐Atlantic. We use evaluation criteria for OBS data and beamforming to enhance the quality of the RFs. Although some stations show reverberations caused by sedimentary cover, we are able to identify the Moho signal, indicating a normal thickness (5–8 km) of oceanic crust. Observations at single stations with thin sediments (300–400 m) indicate that a probable sharp lithosphere‐asthenosphere boundary (LAB) might exist at a depth of ∼70–80 km which is in line with LAB depth estimates for similar lithospheric ages in the Pacific. The mantle discontinuities at ∼410 km and ∼660 km are clearly identifiable. Their delay times are in agreement with PREM. Overall the usage of beam‐formed earthquake recordings for OBS RF analysis is an excellent way to increase the signal quality and the number of usable events.

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Getting over continent ocean boundaries

Eagles

Pérez-Díaz

Scarselli

2015

Earth-Science Reviews

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The idea of a simple linear boundary between continental and oceanic crust at extended continental margins is widely recognised to be an oversimplification. Despite this, such boundaries continue to be mapped because of their perceived utility in palinspastic and plate kinematic reconstructions. To examine whether this perception is justified, we review the data and models on which basis continent ocean boundaries are interpreted, and map a set of such interpretations worldwide from more than 150 publications. The maps show that the location of the continent ocean boundary is rarely consistently estimated within the ~10-100 km observational uncertainty that might be expected of the geophysical data used for doing so, that this is the case regardless of whether the transition zone behind the boundary is classified as magma rich or magma poor, and that the geographical separation of estimates exceeds the width of single-study continent ocean transition zones. The average of global maximum separations across sets of three or more estimates is large (167 km) and mostly a consequence of interpretations published over the last decade. We interpret this to indicate an extra component of uncertainty that is related to authors' understanding of the range of features that are interpretable at extended continental margins. We go on to discuss the implications of this uncertainty for palinspastic and plate kinematic modelling using examples from the literature and from the South Atlantic ocean.We conclude that a precise continent ocean boundary concept with locational uncertainty defined from the ensembles is of limited value for palinspastic reconstructions because the reconstruction process tends to bunch the ensemble within a region that is (i) of similar width to the observational uncertainties associated with continent ocean boundary estimates, (ii) narrower than the regions of uncertainty about rotated features implied by the propagation of uncertainties from plate rotation parameters, and (iii) coincident, within all the above uncertainties, with the more-easily mapped continental shelf gravity anomaly.Secondly, we conclude that estimated continent ocean boundaries are of limited use in developing or testing plate kinematic reconstructions because (i) reconstructions built using them as markers do not, within uncertainty limits defined from the ensembles, differ greatly from those using more-easily determined bathymetric or gravity anomaly contours, and (ii) because it is impossible to segment and date them with useful precision to use as markers of the edges of rigid oceanic lithosphere outside of the constraints of a pre-existing plate kinematic model.

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An integrated geophysical study of Vestbakken Volcanic Province, western Barents Sea continental margin, and adjacent oceanic crust

Cited by 19 publications

References 57 publications

A review of the NE Atlantic conjugate margins based on seismic refraction data

A review of the NE Atlantic conjugate margins based on seismic refraction data

Structure of the oceanic lithosphere and upper mantle north of the Gloria Fault in the eastern mid‐Atlantic by receiver function analysis

Getting over continent ocean boundaries

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