Cristin-resultat-ID: 1779223
Sist endret: 21. januar 2020, 13:39
Resultat
Poster
2019

Dynamic topography development north of Iceland from subaerial exposure and erosion of the igneous Logi Ridge

Bidragsytere:
  • Asbjørn Johan Breivik
  • Pingchuan Tan og
  • Rolf Mjelde

Presentasjon

Navn på arrangementet: AGU Chapman Conference: Large-scale Volcanism in the Arctic: The Role of the Mantle and Tectonics
Sted: Selfoss
Dato fra: 13. oktober 2019
Dato til: 18. desember 2019

Arrangør:

Arrangørnavn: American Geophysical Union

Om resultatet

Poster
Publiseringsår: 2019

Beskrivelse Beskrivelse

Tittel

Dynamic topography development north of Iceland from subaerial exposure and erosion of the igneous Logi Ridge

Sammendrag

The Logi Ridge, located north of the West Jan Mayen Fracture Zone, is E-W oriented and 140-150 km long, terminating in an isolated seamount in the east. The seafloor surrounding the Logi Ridge is ~0.65 km shallower than conjugate seafloor east of the Mohn's Ridge, which has been attributed to dynamic uplift due to asthenospheric flow. Eight reflection seismic lines across the Logi Ridge constrain its development. Both the western and eastern parts have flat tops, indicating erosion at sea-level. Three different basement types surrounding the Logi Ridge are observed: rough basement represents abyssal hills; smooth basement caused by basalt flows overprinting early sediments; and irregular basement formed by basalt flows and intrusions. The surrounding sediments have two distinct units, where the age of the unit boundary is Middle Miocene (~12 Ma). Lava flows and erosion products from the Logi Ridge appears episodically in the lower unit throughout Late Oligocene to Middle Miocene. Ridge development may have started just after the Traill Ø intrusions were emplaced onshore Greenland. No erosion products are seen in the upper unit, proving Middle Miocene submergence. The end of erosion age can also be estimated from seamount height, or present top seamount depth, using the age-dependent oceanic floor subsidence. The two methods have different sensitivity to parameters, which constrains uncertainty when compared. In the west there is good agreement with the age constrained by the sedimentation, proving little dynamic topography change. In the east, discrepancies between the methods are best explained by 0.15-0.3 km increase of dynamic uplift after submergence. Hence, most of the regional dynamic uplift occurred before the end of the Logi Ridge development in the Middle Miocene, suggesting a causative relationship. Minor recent magmatic growth and seafloor uplift over a ~100 km zone southeast of the Logi Ridge may be tied to the younger dynamic uplift in the east.

Bidragsytere

Asbjørn Breivik

Bidragsyterens navn vises på dette resultatet som Asbjørn Johan Breivik
  • Tilknyttet:
    Forfatter
    ved Senter for Jordens utvikling og dynamikk ved Universitetet i Oslo

Pingchuan Tan

  • Tilknyttet:
    Forfatter

Rolf Mjelde

  • Tilknyttet:
    Forfatter
    ved Universitetet i Bergen
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