The area of NW Wedel Jarlsberg Land south of Bellsund (Spitsbergen), between Dunderbukta in the west and the Berzeliustinden mountain group in the east, consists of five fault-bounded blocks: (1) the Renardbreen Block (Middle–Late Proterozoic basement rocks), (2) the Chamberlindalen Block (Late Proterozoic basement rocks), (3) the Martinfjella Block (Late Proterozoic through Early Ordovician basement rocks), (4) the Berzeliustinden Block (Late Proterozoic and Early Ordovician basement rocks covered by Late Palaeozoic–Tertiary platform deposits), (5) the Reinodden Block (Late Palaeozoic and Mesozoic rocks). The paper presents an outline of lithostratigraphy (Middle/Upper Proterozoic–Lower Ordovician: Hecla Hoek Succession) and architecture of the Caledonian basement in which several thrust-sheets and thrust-folds have been recognized. It also discusses some aspects of Tertiary overthrusting, faulting and rotation with affected the basement rocks and remodelled its Caledonian architecture.

A total number of 156 palaeomagnetic specimens of metacarbonates from 9 sites in Blomstrandhalvøya and Lovénøyane (Kongsfjorden, western Spitsbergen) and an additional 77 specimens of unmetamorphosed sediments infilling fractures (4 sites) within the Caledonian metamorphic basement of Blomstrandhalvøya were demagnetized. No relicts of pre-metamorphic magnetization were identified. The Natural Remanent Magnetization (NRM) pattern of metacarbonates is dominated by Caledonian (sensu lato) – Svalbardian and Late Mesozoic/Cenozoic secondary magnetic overprints carried by the pyrrhotite and magnetite/maghemite phases, respectively. The NRM of unmetamorphosed sediments infilling the karstic/tectonic fractures is dominated by hematite carrier. It revealed three stages of magnetization: Caledonian sensu lato, Carboniferous and Late Mesozoic/Cenozoic, which can be related to their initial fracturing, karstification and sedimentation or reactivation. As the majority of the palaeopoles calculated for the Kongsfjorden sites fit the 430 – 0 Ma sector of Laurussia reference path in an in situ orientation these results support the hypothesis that Blomstrandhalvøya and Lovénøyane escaped main Eurekan deformations. The potential rotation of the Kongsfjorden basement by any west dipping listric fault activity rotating the succession accompanying the opening of North Atlantic Ocean was not documented by the palaeomagnetic data presented here.