Publication Date:
2018-07-19
Description:
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.
Type:
Article
,
PeerReviewed
Format:
text
DOI:
10.1016/j.tecto.2011.11.015