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Seismic volcanostratigraphy of the Norwegian Margin: constraints on tectono-magmatic break-up processes

Seismic volcanostratigraphy of the Norwegian Margin: constraints on tectono-magmatic break-up processes
Seismic volcanostratigraphy of the Norwegian Margin: constraints on tectono-magmatic break-up processes
Voluminous volcanism characterized Early Tertiary continental break-up on the mid-Norwegian continental margin. The distribution of the associated extrusive rocks derived from seismic volcanostratigraphy and potential field data interpretation allows us to divide the Møre, Vøring and Lofoten–Vesterålen margins into five segments. The central Møre Margin and the northern Vøring Margin show combinations of volcanic seismic facies units that are characteristic for typical rifted volcanic margins. The Lofoten–Vesterålen Margin, the southern Vøring Margin and the area near the Jan Mayen Fracture Zone show volcanic seismic facies units that are related to small-volume, submarine volcanism. The distribution of subaerial and submarine deposits indicates variations of subsidence along the margin. Vertical movements on the mid-Norwegian margin were primarily controlled by the amount of magmatic crustal thickening, because both the amount of dynamic uplift by the Icelandic mantle plume and the amount of subsidence due to crustal stretching were fairly constant along the margin. Thus, subaerial deposits indicate a large amount of magmatic crustal thickening and an associated reduction in isostatic subsidence, whereas submarine deposits indicate little magmatic thickening and earlier subsidence. From the distribution of volcanic seismic facies units we infer two main reasons for the different amounts of crustal thickening: (1) a general northward decrease of magmatism due to increasing distance from the hot spot and (2) subdued volcanism near the Jan Mayen Fracture Zone as a result of lateral lithospheric heat transport and cooling of the magmatic source region. Furthermore, we interpret small lateral variations in the distribution of volcanic seismic facies units, such as two sets of Inner Seaward Dipping Reflectors on the central Vøring Margin, as indications of crustal fragmentation.
0016-7649
413-426
Berndt, C.
231544d4-f681-44a2-ae6e-74385e588bf6
Planke, S.
5a1032d0-1883-4b28-bbb1-e457b09c3806
Alvestad, E.
16ec6026-e0b0-439a-8e0d-3617e07d4241
Tsikalas, F.
be9739aa-8110-4ea8-b4c2-9b5713bfdef1
Rasmussen, T.
f600932d-7727-4a70-aa99-be570f9fe98c
Berndt, C.
231544d4-f681-44a2-ae6e-74385e588bf6
Planke, S.
5a1032d0-1883-4b28-bbb1-e457b09c3806
Alvestad, E.
16ec6026-e0b0-439a-8e0d-3617e07d4241
Tsikalas, F.
be9739aa-8110-4ea8-b4c2-9b5713bfdef1
Rasmussen, T.
f600932d-7727-4a70-aa99-be570f9fe98c

Berndt, C., Planke, S., Alvestad, E., Tsikalas, F. and Rasmussen, T. (2001) Seismic volcanostratigraphy of the Norwegian Margin: constraints on tectono-magmatic break-up processes. Journal of the Geological Society, 158 (3), 413-426.

Record type: Article

Abstract

Voluminous volcanism characterized Early Tertiary continental break-up on the mid-Norwegian continental margin. The distribution of the associated extrusive rocks derived from seismic volcanostratigraphy and potential field data interpretation allows us to divide the Møre, Vøring and Lofoten–Vesterålen margins into five segments. The central Møre Margin and the northern Vøring Margin show combinations of volcanic seismic facies units that are characteristic for typical rifted volcanic margins. The Lofoten–Vesterålen Margin, the southern Vøring Margin and the area near the Jan Mayen Fracture Zone show volcanic seismic facies units that are related to small-volume, submarine volcanism. The distribution of subaerial and submarine deposits indicates variations of subsidence along the margin. Vertical movements on the mid-Norwegian margin were primarily controlled by the amount of magmatic crustal thickening, because both the amount of dynamic uplift by the Icelandic mantle plume and the amount of subsidence due to crustal stretching were fairly constant along the margin. Thus, subaerial deposits indicate a large amount of magmatic crustal thickening and an associated reduction in isostatic subsidence, whereas submarine deposits indicate little magmatic thickening and earlier subsidence. From the distribution of volcanic seismic facies units we infer two main reasons for the different amounts of crustal thickening: (1) a general northward decrease of magmatism due to increasing distance from the hot spot and (2) subdued volcanism near the Jan Mayen Fracture Zone as a result of lateral lithospheric heat transport and cooling of the magmatic source region. Furthermore, we interpret small lateral variations in the distribution of volcanic seismic facies units, such as two sets of Inner Seaward Dipping Reflectors on the central Vøring Margin, as indications of crustal fragmentation.

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Published date: 1 May 2001

Identifiers

Local EPrints ID: 39311
URI: https://eprints.soton.ac.uk/id/eprint/39311
ISSN: 0016-7649
PURE UUID: 579edbac-f08e-4097-8827-6de854d20231

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Date deposited: 30 Jun 2006
Last modified: 17 Jul 2017 15:37

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Contributors

Author: C. Berndt
Author: S. Planke
Author: E. Alvestad
Author: F. Tsikalas
Author: T. Rasmussen

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