Plate Tectonic Evolution of the Greenland-Scotland Ridge and Surrounding Regions

Nunns, Alan G.

doi:10.1007/978-1-4613-3485-9_2

Cited by 87 publications

(98 citation statements)

References 22 publications

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“…6. On the basis of the pronounced JMFZ and inferred discontinuities, a finite rotation pole describing motion of the Jan Mayen microplate relative to the Eurasia plate between ---50 Ma and 25 Ma was found by trial and error to be at 64ø34'N, 13øW, about 50 km southwest of the pole previously determined by Nunns [1983].…”

Section: Discussionmentioning

confidence: 72%

“…Talwani and Eldholm [1977] identified magnetic anomalies 23 to 7 in the Norway Basin and suggested that fan-shaped, asymmetric spreading had occurred there. Nunns [1983] analyzed a larger magnetic data set and obtained a rotation pole for fan-shaped spreading at 64ø52'N, 12ø18'W. The fan shape is a consequence of the counterclockwise rotation of the Jan Mayen microplate.…”

Section: Introductionmentioning

confidence: 99%

“…According to Nunns [1983] the earliest seafloor spreading between Greenland and Norway took place along the extinct Aegir Ridge at chron C23 or earlier. Between chrons C20 and C7, complementary fan-shaped spreading had occurred about both the Aegir Ridge and the newly formed Kolbeinsey Ridge to the west of the Jan Mayen block.…”

Section: Introductionmentioning

confidence: 99%

“…By doing so we will better understand how the regional asymmetry was formed and envison the crustal accretionary processes more clearly. to 25 Ma, and the solid triangle represents the rotation pole from a past study [Nunns, 1983]. The solid square on the southeastern Aegir Ridge flank represents DSDP site 337.…”

Section: Introductionmentioning

confidence: 99%

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A gravity and magnetic anomaly study of the extinct Aegir Ridge, Norwegian Sea

Jung¹,

Vogt²

1997

J. Geophys. Res.

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Section: Discussionmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A gravity and magnetic anomaly study of the extinct Aegir Ridge, Norwegian Sea

Jung¹,

Vogt²

1997

J. Geophys. Res.

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“…2); by ∼25 Ma the AR was extinct and spreading was completely transferred to the KR (Nunns, 1983;Vogt et al, 1980). Plume influence along the RR at this time is inferred from smooth basement topography created by the part of the RR spreading obliquely (Müller et al, 2008) showing the tectonic evolution of the study area.…”

Section: Introductionmentioning

confidence: 99%

The origin of the asymmetry in the Iceland hotspot along the Mid-Atlantic Ridge from continental breakup to present-day

Howell

Ito

Breivik

et al. 2014

Earth and Planetary Science Letters

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The Iceland hotspot has profoundly influenced the creation of oceanic crust throughout the North Atlantic basin. Enigmatically, the geographic extent of the hotspot influence along the Mid-Atlantic Ridge has been asymmetric for most of the spreading history. This asymmetry is evident in crustal thickness along the present-day ridge system and anomalously shallow seafloor of ages ∼49-25 Ma created at the Reykjanes Ridge (RR), SSW of the hotspot center, compared to deeper seafloor created by the nowextinct Aegir Ridge (AR) the same distance NE of the hotspot center. The cause of this asymmetry is explored with 3-D numerical models that simulate a mantle plume interacting with the ridge system using realistic ridge geometries and spreading rates that evolve from continental breakup to present-day. The models predict plume-influence to be symmetric at continental breakup, then to rapidly contract along the ridges, resulting in widely influenced margins next to uninfluenced oceanic crust. After this initial stage, varying degrees of asymmetry along the mature ridge segments are predicted. Models in which the lithosphere is created by the stiffening of the mantle due to the extraction of water near the base of the melting zone predict a moderate amount of asymmetry; the plume expands NE along the AR ∼70-80% as far as it expands SSW along the RR. Without dehydration stiffening, the lithosphere corresponds to the near-surface, cool, thermal boundary layer; in these cases, the plume is predicted to be even more asymmetric, expanding only 40-50% as far along the AR as it does along the RR. Estimates of asymmetry and seismically measured crustal thicknesses are best explained by model predictions of an Iceland plume volume flux of ∼100-200 m 3 /s, and a lithosphere controlled by a rheology in which dehydration stiffens the mantle, but to a lesser degree than simulated here. The asymmetry of influence along the present-day ridge system is predicted to be a transient configuration in which plume influence along the Reykjanes Ridge is steady, but is still widening along the Kolbeinsey Ridge, as it has been since this ridge formed at ∼25 Ma.

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Origin and evolution of the Kolbeinsey Ridge and Iceland Plateau, N-Atlantic

Brandsdóttír

Hooft

Mjelde

et al. 2015

Geochem. Geophys. Geosyst.

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Variations in crustal structure along the 700 km long KRISE7 refraction/reflection and gravity profile, straddling 66.5 N across the Iceland Shelf, Iceland Plateau and western Norway Basin confirm that extinct spreading centers coexisted with the now extinct AEgir Ridge prior to the initiation of the Kolbeinsey Ridge at 26 Ma. The western 300 km of the profile, across the Iceland shelf, formed by rifting at the Kolbeinsey Ridge, whereas the eastern 400 km, across the Iceland Plateau and the western Norway Basin, formed by earlier rifting, possibly containing slivers of older oceanic or continental crust rifted off the central EGreenland margin along with the Jan Mayen Ridge. Crustal thickness increases gradually across the Iceland shelf, from 12 to 13 km near the Kolbeinsey Ridge to 24-28 km near the eastern shelf edge, decreasing abruptly across the shelf edge, to 12-13 km. The Iceland Plateau has crustal thickness ranging from 12 to 15 km decreasing to 5-8 km across the western Norway Basin and 4-5 km at the AEgir Ridge. We suggest that high-velocity lower crustal domes and corresponding gravity highs across the Iceland plateau mark the location of extinct rift axes that coexisted with the AEgir Ridge. Similar lower crustal domes are associated with the currently active rift segments within Iceland and the Kolbeinsey Ridge.

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Plate Tectonic Evolution of the Greenland-Scotland Ridge and Surrounding Regions

Cited by 87 publications

References 22 publications

A gravity and magnetic anomaly study of the extinct Aegir Ridge, Norwegian Sea

A gravity and magnetic anomaly study of the extinct Aegir Ridge, Norwegian Sea

The origin of the asymmetry in the Iceland hotspot along the Mid-Atlantic Ridge from continental breakup to present-day

Origin and evolution of the Kolbeinsey Ridge and Iceland Plateau, N-Atlantic

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