Strike‐Slip Tectonics in the SW Barents Sea During North Atlantic Rifting (Swaen Graben, Northern Norway)

Abstract

This study uses high‐quality, three‐dimensional (3‐D) seismic data to investigate the occurrence of strike‐slip faults in the Swaen Graben, SW Barents Sea. The Swaen Graben is divided into two principal subbasins: SSB1 and SSB2. The along‐strike and along‐dip displacement variations and scale relationships are analyzed for 42 faults. The displacement profiles for these faults are complex in the Swaen Graben, showing clear evidence for polycyclic fault growth and marked synsedimentary activity. The observed variations in the displacement profiles indicate complex along‐strike segmentation, linkage, and mechanical interactions at distinct structural levels. Along‐dip displacement minima indicate fault reactivation by dip linkage. Importantly, geometric evidence for strike‐slip faulting in the Swaen Graben includes the presence of extensional horsetail splay faults, positive flower structures, and minor transfer faults. This study shows that the faults in the Swaen Graben developed under extensional regimes during Late Jurassic to Early Cretaceous rifting and were reactivated by regional stresses during the Late Cretaceous. The two principal strike‐slip faults in the Swaen Graben reveal sinistral movement and are linked at a shallow depth by minor transfer faults at a relay zone. Our work further demonstrates the occurrence of Late Mesozoic strike‐slip movements in the SW Barents Sea, which were induced by regional tectonics, halokinesis, and fault block rotation. Importantly, strike‐slip faulting in the region extends perhaps into the Cenozoic interacting with extension during the North Atlantic rifting.

Salt‐Detached Strike‐Slip Faulting, Outer Kwanza Basin, Offshore Angola

“…Our determination of Tx (i.e., the point of maximum throw on the fault) is defined by constraining their lateral offset and throw. The lateral offset is defined by measuring the horizontal offset of piercing points across structures (i.e., salt structures, faults, and channels) (e.g., Kim et al., 2001; Peacock, 1991), whereas the throw is defined by measuring, in two‐dimensional cross‐sectional view, the vertical displacement of stratigraphic horizons (e.g., Deng et al., 2019; Omosanya et al., 2017).…”

“…and Omosanya et al (2017). Thus, in stark contrast to normal (e.g., Cartwright et al, 1995;Childs et al, 2017;Dawers et al, 1993;Rotevatn et al, 2019;Walsh et al, 2002;Walsh & Watterson, 1988) and even reverse (e.g., Bergen & Shaw, 2010;Higgins et al, 2009) faults, which have been extensively studied, we have a relatively poor understanding of the four-dimensional structure and growth of strike-slip fault arrays.…”