Seafloor expression and shallow structure of a fold-and-thrust system, Isfjorden, west Spitsbergen

• Published in: Polar research Vol. 31; no. 1; pp. 11209 - 13
• Main Authors: Blinova, Maria, Inge Faleide, Jan, Gabrielsen, Roy H., Mjelde, Rolf
• Format: Journal Article
• Language: English
• Published: Routledge 01-01-2012; Norwegian Polar Institute
• Subjects: Isfjorden; Marine; seafloor morphology; seismic interpretation; shallow structures; Svalbard; west Spitsbergen fold-and-thrust belt; PNE, Norway, Svalbard, Spitsbergen, Isfjorden; Norway, Svalbard, Spitsbergen
• DOI: 10.3402/polar.v31i0.11209
• EISSN: 1751-8369
• ISSN: 1751-8369; 0800-0395

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 north-west-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 Jurassic-Cretaceous outcrops on the seafloor. Subarea 3 is situated east of the main thrust fault T3 and mainly involves outcrops of Triassic-Jurassic rocks. Together, Subareas 2 and 3 are dominated by foreland-directed, north-west-south-east and NNW-SSE-striking thrusts that are hardly detectable in bathymetric data.