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

TY - JOUR

T1 - Crustal structure across the Møre margin, mid-Norway, from wide-angle seismic and gravity data

AU - Kvarven, Trond

AU - Ebbing, Jörg

AU - Mjelde, R.

AU - Faleide, Jan Inge

AU - Libak, Audun

AU - Thybo, Hans

AU - Flueh, Ernst R.

AU - Murai, Yoshio

PY - 2014

Y1 - 2014

N2 - The Møre 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 bottomseismometer profileswith deep seismic reflection and refraction datawere acquired in 2009; two dip-profiles which were extended by land stations, and one tie-profile parallel to the strike of the Møre-Trøndelag 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 Møre 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 Trøndelag Platform, but not under the Slørebotn Sub-basin. Furthermore, two lower crustal high-velocity bodies are modeled, one located near the Møre Marginal High and one beneath the Slørebotn 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.

AB - The Møre 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 bottomseismometer profileswith deep seismic reflection and refraction datawere acquired in 2009; two dip-profiles which were extended by land stations, and one tie-profile parallel to the strike of the Møre-Trøndelag 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 Møre 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 Trøndelag Platform, but not under the Slørebotn Sub-basin. Furthermore, two lower crustal high-velocity bodies are modeled, one located near the Møre Marginal High and one beneath the Slørebotn 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.

U2 - 10.1016/j.tecto.2014.03.021

DO - 10.1016/j.tecto.2014.03.021

M3 - Journal article

SN - 0040-1951

VL - 626

SP - 21

EP - 40

JO - Tectonophysics

JF - Tectonophysics

ER -