Reactivation history of the long-lived Billefjorden Fault Zone in north central Spitsbergen, Svalbard

Abstract

New geological mapping has revealed further details of the tectonic and stratigraphic effects of Devonian and later reactivations of the Billefjorden Fault Zone, one of a number of important north-south trending lineaments in Svalbard. Analysis of offsets along the many steeply-dipping faults within the zone, and effects on the subsidence and deformation of the adjacent crustal blocks, is presented as a series of tectonic maps from the Late Devonian through to the Tertiary. Late Devonian sinistral transpression, suggested previously, cannot be ruled out, and Carboniferous reactivation was dominated by extension, with possibly a slight dextral strike-slip component. After Late Carboniferous to Early Cretaceous platform subsidence, during which the fault zone had little effect on sedimentation, development of the Tertiary West Spitsbergen Fold Belt (related to the opening of the Arctic Ocean) involved compressive (and transpressive?) reactivation of basement-seated structures further east, including the Billefjorden Fault Zone. In the Billefjorden-Austfjorden area this produced a large monoclinal fold across the fault zone, which was later cross-cut by extensional structures to produce the present day Billefjorden syncline. This localized late extension is related to a slight variation in the trend of the Billefjorden Fault Zone through this area.

Middle to Late Devonian–Carboniferous collapse basins on the Finnmark Platform and in the southwesternmost Nordkapp basin, SW Barents Sea

“…2). This succession consists of alluvial clastic sedimentary rocks that are progressively replaced upwards by shallow marine platform carbonates interbedded with clastic and evaporite deposits (McCann and Dallmann, 1996). In well 7124/3-1 (Fig.…”

Eurekan transpressive deformation in the Wandel Hav Mobile Belt (northeast Greenland)

“…[64] In Spitsbergen, normal faulting during Carboniferous times has been described by, for example, , Gjelberg and Steel [1981], Steel and Worsley [1984], Ringset and Andresen [1988], Johannessen and Steel [1992], Dallmann [1992], Dallmann et al [1993a], McCann and Dallmann [1996], and CASE Team [2001]. The most prominent structures are the Billefjorden Fault Zone and Lomfjorden Fault Zone in the east (Figure 19a), the Inner Hornsund Fault in the south, and additional fault bounded basins in the west [e.g., Maher and Welbon, 1992;Welbon and Maher, 1992;.…”

“…This applies to the Billefjorden and Lomfjorden Fault Zones in the east [e.g., Nøttvedt et al, 1988;Ringset and Andresen, 1988;Haremo et al, 1990;McCann and Dallmann, 1996] but also to southern and western parts within the fold-and-thrust belt proper [e.g., Dallmann, 1992;Maher and Welbon, 1992;Welbon and Maher, 1992;CASE Team, 2001].…”

3D restoration of a Cretaceous rift basin in Kilen, eastern North Greenland

“…Large, Late Palaeozoic lineaments of the Billefjorden and Lomfjorden fault complexes were not reactivated during the Late Mesozoic (Haremo et al, 1990;Dypvik et al, 1991;McCann & Dallmann, 1996).…”