Figure 9. Schematic model of the interaction of WNW–ESE-striking Timanian faults and N–S-striking Caledonian and Eurekan faults in Svalbard during the opening of the Fram Strait.

( a) Inherited, late Neoproterozoic Timanian thrust systems such as the Kinnhøgda–Daudbjørnpynten and Kongsfjorden–Cowanodden fault zones (KDFZ and KCFZ; red lines) are reactivated as sinistral strike-slip faults during oblique extension and localize the formation of major transform faults, the Spitsbergen and Molloy fault zones (SPZ and MFZ; dashed yellow lines). ( b) Preexisting NNE–SSW-striking (e.g., Caledonian and Eurekan) structural grain and fabrics are reactivated as local dextral strike-slip faults (orange lines) to accommodate tectonic adjustments during NW–SE-oriented extension and NW–SE-striking transform faulting. WNW–ESE-striking transtensional folds form parallel to the extension direction and to reactivated Timanian thrust systems. The green line shows the amount of dextral movement along N–S-striking faults, i.e., a few km up to 10 km, and the blue line sinistral movement along WNW–ESE-striking faults, which is in the order of a few tens of km. Notice how this tectonic setting may give the illusion that the main transform fault strikes N–S instead of NW–SE due to the relatively larger number of N–S-dextral faults in the area. This impression is reinforced if the main few NW–SE-striking faults do not crop out or if related outcrops are of poor quality. Abbreviations: IYF: Isfjorden–Ymerbukta Fault; KCFZ: Kongsfjorden–Cowanodden fault zone; KDFZ: Kinnhøgda–Daudbjørnpynten fault zone; MFZ: Molloy fault zone; SEDL: Svartfjella–Eidembukta–Daudmannsodden Lineament; SFZ: Spitsbergen fault zone.