Crustal structure between the Knipovich Ridge and the Van Mijenfjorden (Svalbard)

Ritzmann, O.; Jokat, Wilfried; Mjelde, Rolf; Shimamura, Hideki

doi:10.1023/b:mari.0000018168.89762.a4

Cited by 53 publications

(46 citation statements)

References 46 publications

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“…Ritzmann et al [2002] and Kandilarov et al [2008] report quite similar crustal thicknesses north of the Logachev Seamount (SMC #7) of 3.7 km and 3.5 km, respectively. Ljones et al [2004] reported a crustal thickness of 5.5 km south of SMC #9.…”

Section: Discussionmentioning

confidence: 95%

“…The amagmatic segments seem to correlate with a massive exposure of mantle peridotites along the Gakkel Ridge [Michael et al, 2003;Standish et al, 2008]. Geophysical studies along ultraslow ridges like the Knipovich Ridge [Ritzmann et al, 2002;Ljones et al, 2004;Kandilarov et al, 2008Kandilarov et al, , 2010, the Gakkel Ridge [Jokat et al, 2003;Jokat and SchmidtAursch, 2007] and the Southwest Indian Ridge [Muller et al, 1999;Minshull et al, 2006] show that such ridges have in general anomalously thin crust of 2-4 km, which thickens to 6-7 km at axial volcanic highs.…”

Section: Introductionmentioning

confidence: 97%

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Crustal thickness and earthquake distribution south of the Logachev Seamount, Knipovich Ridge

Jokat

Kollofrath

Geissler

et al. 2012

Geophysical Research Letters

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During RV Polarstern cruise ARK‐XXIV/3 (2009), a geophysical study along the ultraslow spreading Knipovich Ridge was conducted. The survey, located in the rift valley south of the Logachev Seamount (∼76°36′N), provides a crustal thickness of ∼4.5 km in the amagmatic parts and 5.7 km underneath the seamount itself. The velocity‐depth function indicates the presence of a thick oceanic layer 2 (4.5 km), but no indication for a thick oceanic layer 3. The only exception is the area underneath the Logachev Seamount, where velocities higher than 6 km/s are detected. This indicates a stronger and focussed melt supply underneath the seamount. Local seismicity was analysed for two days. In total, 191 quakes were identified in the vicinity of the rift valley with magnitudes up to ML = 2.6. At least 48 of them are located in the upper mantle (up to 18 km below sea level), supporting models predicting a cold mantle or conductive cooling underneath ultraslow ridges to explain the reduced melt supply.

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Section: Discussionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 97%

Crustal thickness and earthquake distribution south of the Logachev Seamount, Knipovich Ridge

Jokat

Kollofrath

Geissler

et al. 2012

Geophysical Research Letters

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“…, while a layer 3 could not be mapped (Ritzmann et al 2002). Velocities of 7.3 -8.0 km s 21 beneath the oceanic crust indicate a partial serpentinization of the mantle rocks.…”

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confidence: 90%

“…Between model km 150 and 180, a region with increased lower-crustal velocities (.7.2 km s 21 ) is observed, although the seismic resolution is low. Ritzmann et al (2002) related these velocities to magmatic intrusions of unknown origin. The nature of the deep sedimentary basin landward of the COB is not clear and the depth of the crystalline basement is not resolved by the data.…”

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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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“…The Norwegian Sea, SW Barents Sea and Svalbard margins are well-studied with extensive deep seismic studies [e.g., Faleide et al, 1991;Mjelde et al, 1997Mjelde et al, , 1998Mjelde et al, , 2002aMjelde et al, , 2005Ritzmann et al, 2002Ritzmann et al, , 2004Breivik et al, 2003Breivik et al, , 2006. In contrast, few deep seismic studies exist across the conjugate NE Greenland margin [Voss and Jokat, 2007;Jokat et al, 2004] and, so far, none to the north of 76°N.…”

Section: Introductionmentioning

confidence: 99%

East Greenland Ridge in the North Atlantic Ocean: An integrated geophysical study of a continental sliver in a boundary transform fault setting

et al. 2008

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The combined Greenland‐Senja Fracture Zones (GSFZ) represent a first‐order plate tectonic feature in the North Atlantic Ocean. The GSFZ defines an abrupt change in the character of magnetic anomalies with well‐defined seafloor spreading anomalies in the Greenland and Norwegian basins to the south but ambiguous and weak magnetic anomalies in the Boreas Basin to the north. Substantial uncertainty exists concerning the plate tectonic evolution of the latter area, including the role of the East Greenland Ridge, which is situated along the Greenland Fracture Zone. In 2002, a combined ocean‐bottom seismometer and multichannel seismic (MCS) survey acquired two intersecting wide‐angle reflection and coincident MCS profiles across and along the East Greenland Ridge. We present the results of integrated reflection seismic interpretation, first‐arrival tomography, 2D kinematic raytracing, full‐wave amplitude modeling, and gravity modeling of the intersecting profiles. The results show that (1) the Greenland Basin is characterized by a normal oceanic crustal velocity structure, (2) the velocity structure of the East Greenland Ridge is of overall continental type, and (3) a major faulted basin province above highly extended continental crust exists to the NE of the ridge. The results further suggest that a zone of extremely thin and faulted continental crust above partially serpentinized mantle peridotite defines the NW edge of the East Greenland Ridge and the transition to the NE Greenland margin.

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Crustal structure between the Knipovich Ridge and the Van Mijenfjorden (Svalbard)

Cited by 53 publications

References 46 publications

Crustal thickness and earthquake distribution south of the Logachev Seamount, Knipovich Ridge

Crustal thickness and earthquake distribution south of the Logachev Seamount, Knipovich Ridge

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

East Greenland Ridge in the North Atlantic Ocean: An integrated geophysical study of a continental sliver in a boundary transform fault setting

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