2-D and 3-D modelling of wide-angle seismic data: an example from the Vøring volcanic passive margin

Rouzo, S.; Klingelhöfer, F.; Jonquet-KolstØ, H.; Karpuz, R.; Kravik, K.; Mjelde, Rolf; Murai, Yoshio; Raum, T.; Shimamura, Hideki; Williamson, P.; Géli, Louis

doi:10.1007/s11001-006-0001-3

Cited by 8 publications

(7 citation statements)

References 25 publications

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“…On the refraction profile 6‐00 (Raum et al, ; Figure C), the T ‐Reflection is associated with velocities ranging between 5 and 6 km/s. However, P wave velocity of 7+ km/s have been modeled at the level of the T ‐Reflection, along the same transect (Rouzo et al, ), showing already that OBS modeling can produce a large range of uncertainties.…”

Section: Discussionmentioning

confidence: 94%

“…Furthermore, high V p velocities on the Rån Ridge have been interpreted as indication of the existence of a deep seated eclogite body ( Figure 9C; e.g., Raum et al, 2006). However, we note that an alternative model suggests that the T-Reflection coincides with velocities of up to 7 km/s (Rouzo et al, 2006).…”

Section: -D Comparisonmentioning

confidence: 84%

“…In later studies, these reflections have been regionally mapped along the outer Vøring Basin and named the T ‐Reflection (Gernigon et al, ). In the North and South Gjallar ridges, Gernigon et al () further discussed the definition and structural interpretation of the T ‐Reflection and suggested that it coincides with the top of the continental part of the LCB geophysically modeled at approximately the same depth based on ocean bottom seismometer (OBS) data (Mjelde, Faleide, et al, ; Rouzo et al, ; Figure ). The part of the LCB imaged beneath the North Gjallar Ridge appears to have been emplaced before the main volcanic event and influenced the faulting and distal development of the sedimentary basin at least 10–15 Ma before the breakup and the main magmatic event (Gernigon et al, ).…”

Section: Introductionmentioning

confidence: 99%

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The T‐Reflection and the Deep Crustal Structure of the Vøring Margin, Offshore mid‐Norway

et al. 2017

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Seismic reflection data along volcanic passive margins frequently provide imaging of strong and laterally continuous reflections in the middle and lower crust. We have completed a detailed 2‐D seismic interpretation of the deep crustal structure of the Vøring Margin, offshore mid‐Norway, where high‐quality seismic data allow the identification of high‐amplitude reflections, locally referred to as the T‐Reflection. Using a dense seismic grid, we have mapped the geometry of the T‐Reflection in order to compare it with filtered Bouguer gravity anomalies and seismic refraction data. The T‐Reflection is identified between 7 and 10 s. Sometimes it consists of one single smooth reflection. However, it is frequently associated with a set of rough multiple reflections displaying discontinuous segments with varying geometries, amplitudes, and contact relationships. The T‐Reflection seems to be connected to deep sill networks and is locally identified at the continuation of basement high structures or terminates over fractures and faults. The T‐Reflection presents a low magnetic signal. The spatial correlation between the filtered positive Bouguer gravity anomalies and the deep dome‐shaped reflections indicates that the latter represent a high‐impedance boundary contrast associated with a high‐density and high‐velocity body. In ~50% of the outer Vøring Margin, the depth of the mapped T‐Reflection is found to correspond to the depth of the top of the Lower Crustal Body (LCB), which is characterized by high P wave velocities (>7 km/s). We present a tectonic scenario, where a large part of the deep crustal structure is composed of preserved upper continental crustal blocks and middle to lower crustal lenses of inherited high‐grade metamorphic rocks. Deep intrusions into the faulted crustal blocks are responsible for the rough character of the T‐Reflection, whereas intrusions into the ductile lower crust and detachment faults are likely responsible for its smoother character. Deep magma intrusions can be responsible for regional metamorphic processes leading to an increasing velocity of the lower crust to more than 7 km/s. The result is a heterogeneous LCB that likely represents a complex mixture of pre‐ to syn‐breakup mafic and ultramafic rocks (cumulates and sills) and old metamorphic rocks such as granulites and eclogites. An increasing degree of melting toward the breakup axis is responsible for an increasing proportion of cumulates and sill intrusions in the lower crust.

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Section: Discussionmentioning

confidence: 94%

Section: -D Comparisonmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

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The T‐Reflection and the Deep Crustal Structure of the Vøring Margin, Offshore mid‐Norway

et al. 2017

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“…This HVLC is accordingly explained as eclogite because the velocities are too high for both crustal crystalline rocks and mantle peridotite. Other studies use much lower densities for gravity modelling (Rouzo et al 2006;Reynisson et al 2010) and the 3D complexity of the area might suggest that 2D seismic refraction profiles did not adequately map the deep crustal structures in sufficient detail. In contrast, velocities between 7.0 and 7.8 km s 21 could represent both mafic intrusions (including magmatic underplating) and partially serpentinized mantle peridotite (Miller & Christensen 1997;Christensen 2004).…”

Section: Mid-norwegian Continental Marginmentioning

confidence: 99%

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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“…These observations may indicate that they are genetically unrelated. We note that the > 8 km/s body in the southern Vøring Basin was not included in the final model presented by Rouzo et al (2006), who performed a 3D modeling of parts of the OBS data in that area. Their modeling was focused on the sedimentary and upper crystalline section, and did not include lower crustal/upper mantle arrivals.…”

Section: The Moho and +8 Km/s Bodiesmentioning

confidence: 99%

Crustal structure and evolution of the outer Møre Margin, NE Atlantic

et al. 2009

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Five regional Ocean Bottom Seismic profiles from the northwestern part of the Møre Margin, NE Atlantic, have been modeled with regard to crustal structure, and the interpretations have been supported by the use of multi-channel seismic and potential field data. The chi-squared values (uncertainty) for the studied profiles are generally in the range 1-3, and the uncertainty in the Moho depth is estimated to +/-1 km. The Continent-Ocean-Transition is found to be relatively sharp (10-40 km wide) expressing a change in physical properties corresponding to felsic continental crust along the landward part of the marginal high (V p =6.2-6.5 km/s), and thick, mafic oceanic crust further northwestwards. The Early Eocene breakup was associated with excessive magmatism, and the models document direct continuity between this magmatism and a lower crustal high-velocity layer in the Møre Basin (V p =7.1-7.3 km/s), suggesting a genetic link. The Jan Mayen Lineament is observed across the entire study area as northeastward termination of the lower crustal body, as well as structuring in the top of the crystalline basement and the Moho. We present a 2 speculative model involving lower crustal bodies of eclogites (Vp > 8 km/s) inferred in the easternmost part of the Møre Basin linking the Jan Mayen Lineament to the post-Caledonian Nordfjord-Sogn Detachment.

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2-D and 3-D modelling of wide-angle seismic data: an example from the Vøring volcanic passive margin

Cited by 8 publications

References 25 publications

The T‐Reflection and the Deep Crustal Structure of the Vøring Margin, Offshore mid‐Norway

The T‐Reflection and the Deep Crustal Structure of the Vøring Margin, Offshore mid‐Norway

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

Crustal structure and evolution of the outer Møre Margin, NE Atlantic

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