Abstract
A new 3D geophysical model for the greater Barents Sea Region was
developed by the University of Oslo, NORSAR and the U.S. Geological
Survey. A considerable amount of continuous seismic velocity transects
were compiled and deep-seismic multi-channel data in the SW was further
used for density modeling and subsequent density-to-velocity conversion.The
final velocity model consists of five crustal layers. The model compilation
introduced in this study is based on geological provinces of different
sizes, such as sedimentary basins, structural highs or volcanic provinces
with individual sedimentary, tectonic and magmatic histories. Firstly,
the layer velocities and thicknesses were laterally inter- and extrapolated.
Within the provinces, linear relationships between the thickness
of the sedimentary rocks and the thickness of the remaining crystalline
crust are observed. We used therefore the additionally compiled (area-wide)
depth-to-basement data to adjust the crystalline crustal thickness
according to the sedimentary thickness where no data constraints
are given. After the compilation, the p-wave velocity model was converted
into a density model, in order to test the structure against independent
gravity data and to model densities for each layer. Our model is
completed by an upper mantle surface wave inversion model. The resultant
model was subsequently verified in terms of traveltimes. In order
to do so, we compiled a list of well-located reference events and
arrival times not used to construct the model. Within the uncertainty
limits, modeled traveltimes fit the available observations and qualitatively
validate the model. An outstanding improvement compared to other
(older) geophysical models is the high resolution of 50 km throughout
the target region. Velocity transects through the 3D model and a
new depth-to-Moho map exemplifies geological features of the European
Arctic and the formerly unknown diversity of the crustal structure
in the greater Barents Sea region.
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