Palaeoproterozoic foreland fold-thrust belt structures and lateral faults in the West Troms Basement Complex, northern Norway, and their relation to inverted metasedimentary sequences

Palaeoproterozoic fold-thrust belt structures and steep, lateral shear zones characterize the foreland deformation of Neoarchaean basement tonalites in Vanna, West Troms Basement Complex, northern Norway. Low-grade par-autochthonous allochthonous cover units (2.4–2.2. Ga) with sandstones calcareous metapelites exist separate areas foreland. They were formed as intracontinental rift- and/or deltaic shelf deposits, subsequently intruded by a diorite sill at c. 2.2 Ga. The folded inverted along low-angle thrusts steep reverse faults during two late/post Svecofennian (1.77–1.63 orthogonal shortening events (D1-D2). D1 event involved NE-SW shortening, folding, ENE-directed thrusting, dextral shearing, controlled pre-existing, N-S striking mafic dykes (c. 2.4 basin-bounding normal faults. D2 SE vergent nappe translation, flat-ramp thrust propagation frontal duplex above basement-seated detachment, sinistral reactivation partitioned orogen-parallel, transpressive setting. Hydrothermal fluid circulation affected all zones. New aeromagnetic data show basement-involved architecture well. Vanna Island styles resemble other rift-basin deposits Fennoscandia, deformed Orogeny (1.92–1.79 Ga), Alta-Kautokeino Karasjok greenstone belts Norway, Central Lapland, Peräpohja, Kittilä Kuusamo Finland, Norrbotten province Sweden. Westward younging orogenic explain younger age span on Island.