Pre-existing normal faults have limited control on the rift geometry of the northern North Sea

Abstract

18Many rifts develop in response to multiphase extension with numerical and

The Influence of Structural Inheritance and Multiphase Extension on Rift Development, the NorthernNorth Sea

“…Structural measurements were converted from the time to the depth domains using the velocity model of Fazlikhani et al (), with those at deeper levels of the basin converted using interval velocities from Christiansson et al (). Although parts of these surveys have been interpreted in local studies (e.g., Claringbould et al, ; Deng, Fossen, et al, ; Duffy et al, ), this represents one of the first studies to integrate the available data with observations from these local studies to resolve the regional multiphase rift evolution of the whole of the northern North Sea.…”

“…A period of relative tectonic quiescence followed RP1 (Coward et al, ; Ziegler, ), although some faults remained active during this so‐called “interrift” period (Claringbould et al, ; Deng, Fossen, et al, ). Early‐Middle Jurassic thermal doming in the Central North Sea resulted in the erosion and removal of large thicknesses of strata across large parts of the North Sea (Davies et al, ; Quirie et al, ; Underhill & Partington, ).…”

“…Earlier phases of extension may also modify the crustal and lithospheric structure of rift systems. Faults related to earlier rift phases interact with, and may exhibit controls over the growth of newly formed normal faults (e.g., Bell et al, ; Claringbould et al, ; Deng, Fossen, et al, ; Duffy et al, ; Henstra et al, ; Henstra et al, ; Morley, ; Nixon et al, ); while, at the whole‐rift scale, lithospheric thinning associated with earlier phases of extension may focus strain during later rift phases (e.g., Boone et al, ; Brune et al, ; Claringbould et al, ; Cowie et al, ; Naliboff & Buiter, ; Odinsen et al, ). Previous studies often focused on local (less than tens of kilometers) scale aspects of the influence of preexisting structural heterogeneities on rift geometry and kinematics, with relatively few studies examining the regional, whole‐rift (hundreds of kilometers) scale (Corti, ; Daly et al, ; Fazlikhani et al, ; Morley, ).…”

How do pre‐existing normal faults influence rift geometry? A comparison of adjacent basins with contrasting underlying structure on the Lofoten Margin, Norway

“…This hypothesis may also help explain why pre‐existing faults that juxtapose similar lithologies on either side of the fault in some other multiphase rifts are not reactivated. For example, in east Shetland Basin, pre‐existing faults that juxtapose sedimentary rocks against sedimentary rocks did not influence later rift geometry (Claringbould et al, ). To our knowledge, the influence of a contrast in rheology between foot‐ and hanging wall rock on the likelihood of fault reactivation is not well understood and forms an interesting topic for future research.…”

“…Deng, Gawthorpe, Finch, and Fossen (2017) discuss styles of normal fault reactivation during multiphase rifting and distinguish between upward propagation and vertical linkage (see also Giba, Walsh, & Nicol, 2012;Walsh, Nicol, & Childs, 2002). Claringbould, Bell, Jackson, Gawthorpe, and Odinsen (2017), however, demonstrated that not all multiphase-rifted basins involve reactivation of pre-existing normal faults (see also Lee & Hwang, 1993;Tomasso, Underhill, Hodgkinson, & Young, 2008). In cases where pre-existing structural fabric (faults or shear zones) is not reactivated directly, the presence of crustal heterogeneity may still exert control by influencing the location and reorienting the strike of younger rift faults (Phillips, Jackson, Bell, Duffy, & Fossen, 2016;Rotevatn, Kristensen, et al, 2018).…”