Analysis of structural trends of sub-sea-floor strata in the Isfjorden area of the West Spitsbergen Fold-and-Thrust Belt based on multichannel seismic data

作者：Blinova Maria^*; Faleide Jan Inge; Gabrielsen Roy H; Mjelde Rolf

来源：Journal of the Geological Society, 2013, 170(4): 657-668.

DOI：10.1144/jgs2012-109

A dense grid of 2D multichannel seismic data was used for the interpretation of sub-sea-floor structures in the area of Isfjorden in western Spitsbergen. West Spitsbergen underwent Eocene transpressional deformation that resulted in formation of the West Spitsbergen Fold-and-Thrust Belt. Three horizons were defined for the seismic interpretation as well-expressed and continuous reflections: (1) the top of the metamorphic basement; (2) the base of the upper Carboniferous Nordenskioldbreen Formation; (3) the base of the Lower Cretaceous Helvetiafjellet Formation. Time-structure maps and analysis of the sub-bottom structural trends were generated for each horizon. The top of the metamorphic basement displays north-south-trending graben structures, apparently representing continuation of the Devonian grabens from northern Spitsbergen. The tectonostratigraphic unit bounded by the base of the upper Carboniferous Nordenskioldbreen Formation and base of the Helvetiafjellet Formation encloses the fold-and-thrust belt and is affiliated with WSW-ENE shortening involving three decollement levels. Within this unit the strata between the middle (Triassic shales) and upper (Upper Jurassic shales) decollements have undergone the most intense strain, whereas sediments situated between the basal (lower Permian evaporites) and middle decollements underwent a relatively mild deformation. The strata above the base of the Helvetiafjellet Formation are characterized by minor Tertiary deformation only.

• 出版日期2013-7