Publication Date:
2019-09-23
Description:
We present results from an active-source, onshore–offshore seismic reflection/refraction transect acquired as
part of the PETROBAR project (Petroleum-related studies of the Barents Sea region). The 700 km-long profile
is oriented NW–SE, coincident with previously published multichannel seismic reflection profiles. We utilize
layer-based raytracing in a Markov Chain Monte Carlo (MCMC) inversion to determine a probabilistic velocity
model constraining the sedimentary rocks, crystalline crust, and uppermost mantle in a complex tectonic regime.
The profile images a wide range of crustal types and ages, fromProterozoic craton to Paleozoic to early Cenozoic
rift basins; and volcanics related to Eocene continental breakupwith Greenland. Our analyses indicate a complex
architecture of the crystalline crust along the profile,with crystalline crustal thicknesses ranging from43 kmbeneath
the Varanger Peninsula to 12 kmbeneath the Bjørnøya Basin. Assuming an original, post-Caledonide crustal
thickness of 35 km in the offshore area, we calculate the cumulative thinning (β) factors along the entire
profile. The average β factor along the profile is 1.7 ± 0.1, suggesting 211–243 km of extension, consistent
with the amount of overlap derived from published plate reconstructions. Local β factors approach 3, where
Bjørnøya Basin reaches a depth of more than 13 km. Volcanics, carbonates, salt, diagenesis and metamorphism
make deep sedimentary basin fill difficult to distinguish from original, pre-rift crystalline crust, and thus actual
stretching may in places exceed our estimates.
Type:
Article
,
PeerReviewed
Format:
text
DOI:
10.1016/j.tecto.2013.02.033
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