Mafic intrusions east of Svalbard imaged by active-source seismic tomography

Minakov, Alexander, Mjelde, Rolf, Faleide, Jan Inge, Flueh, Ernst R., Dannowski, Anke and Keers, Henk (2012) Mafic intrusions east of Svalbard imaged by active-source seismic tomography Tectonophysics, 518/521 . pp. 106-118. DOI 10.1016/j.tecto.2011.11.015.

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A seismic refraction and reflection tomography experiment was performed across the igneous province east
of Svalbard which is a part of the Cretaceous High Arctic Large Igneous Province. Seismic travel times from 12
ocean bottom seismometers/hydrophones deployed along a 170 km line are inverted to produce smooth 2D
images of the crustal P-wave velocity and geometry of the acoustic basement and Moho. The inversion of
travel times was complemented by forward elastic wave propagation modeling. Integration with onshore geology
as well as multichannel seismic, magnetic and gravity data have provide additional constraints used in
the geological interpretation. The seismic P-wave velocity increases rapidly with depth, starting with 3 km/s
at the sea floor and reaching 5.5 km/s at the bottom of the upper sedimentary layer. The thickness of this
layer increases eastward from 2 km to 3.5 km. On average the P-wave velocity in the crystalline crust increases
with depth from 5.5 km/s to 6.8 km/s. The crustal thickness is typical for continental shelf regions
(30–34 km). Finger-shaped high-velocity anomalies, one reaching 12% and two of 4–6% velocity perturbation,
are obtained. These velocity anomalies are concomitant with Lower Cretaceous basaltic lava flows and
sills in the shallow sediments and elongated gravity and magnetic highs, traced towards the northern Barents
Sea passive continental margin. We interpret the obtained velocity anomalies as signatures of dikes emplaced
in the basement during breakup and subsequent spreading in the Arctic Amerasia Basin.

Document Type: Article
Keywords: Seismology; Meeresgeologie; Svalbard ; Magmatism ; Mafic intrusions ; Seismic tomography ; Dike swarms ; High-Arctic Large Igneous Province
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
OceanRep > The Future Ocean - Cluster of Excellence
Refereed: Yes
DOI etc.: 10.1016/j.tecto.2011.11.015
ISSN: 0040-1951
Projects: Future Ocean
Date Deposited: 09 Jan 2012 10:40
Last Modified: 15 Jun 2016 11:58

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