Seafloor expression and shallow structure of a fold-and-thrust system, Isfjorden, west Spitsbergen
A detailed map of the structure of the west Spitsbergen fold-and-thrust belt in the Isfjorden area, Spitsbergen, is presented. The map was constructed from a dense grid of two-dimensional multichannel reflection seismic and bathymetric data. Joint interpretation of two data sets allowed a comparison of tectonic structures detected along the uppermost parts of the seismic sections and those reflected in the morphology of the seafloor. Three major, predominantly northwest south-east striking faults were identified. The westernmost fault (T1) is a hinterland-directed (most likely out of sequence) thrust, while the central and easternmost faults (T2 and T3) are foreland-directed (in-sequence thrusts). The thrusts divide Isfjorden into three subareas. Subarea 1 is bounded by thrust faults T1 and T2 and comprises Tertiary rocks surrounded by Jurassic- Cretaceous strata. The structural signature of Subarea 1 is that of a system of hinterland- and foreland-directed thrust faults, resulting in a seafloor relief characterized by parallel ridges and troughs. Subarea 2 is limited by thrust faults T2 and T3 and shows JurassicCretaceous outcrops on the seafloor. Subarea 3 is situated east of the main thrust fault T3 and mainly involves outcrops of TriassicJurassic rocks. Together, Subareas 2 and 3 are dominated by forelanddirected, north-westsouth-east and NNWSSE-striking thrusts that are hardly detectable in bathymetric data.
Keywords: Svalbard; Isfjorden; west Spitsbergen fold-and-thrust belt; seismic interpretation; seafloor morphology; shallow structures
(Published: 5 September 2012)
Citation: Polar Research 2012, 31, 11209, http://dx.doi.org/10.3402/polar.v31i0.11209
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Authors retain copyright of their work, with first publication rights granted to the Norwegian Polar Institute.