open access

https://hdl.handle.net/2115/56858

Crustal structure across the More margin, mid-Norway, from wide-angle seismic and gravity data

英語

Jan Mayen Lineament

2014-06-20

Elsevier

Tectonophysics

626

21-40

The More Margin in the NE Atlantic represents a dominantly passive margin with an unusual abrupt transition from alpine morphology onshore to a deep sedimentary basin offshore. In order to study this transition in detail, three ocean bottom seismometer profiles with deep seismic reflection and refraction data were acquired in 2009; two dip-profiles which were extended by land stations, and one tie-profile parallel to the strike of the More-Trondelag Fault Complex. The modeling of the wide-angle seismic data was performed with a combined inversion and forward modeling approach and validated with a 3D-density model. Modeling of the geophysical data indicates the presence of a 12-15 km thick accumulation of sedimentary rocks in the More Basin. The modeling of the strike profile located closer to land shows a decrease in crustal velocity from north to south. Near the coast we observe an intra-crustal reflector under the Trondelag Platform, but not under the Slorebotn Sub-basin. Furthermore, two lower crustal high-velocity bodies are modeled, one located near the More Marginal High and one beneath the Slorebotn Sub-basin. While the outer lower crustal body is modeled with a density allowing an interpretation as magmatic underplating, the inner body has a density close to mantle density which might suggest an origin as an eclogized body, formed by metamorphosis of lower crustal gabbro during the Caledonian orogeny. The difference in velocity and extent of the lower crustal bodies seems to be controlled by the Jan Mayen Lineament, suggesting that the lineament represents a pre-Caledonian structural feature in the basement.

学術雑誌論文

Accepted Manuscript

(C) 2014 Elsevier B.V. All rights reserved.

0040-1951