Metamorphic and structural studies of basement rocks, NE Svalbard
The complexes are subdivided into three different tectonic provinces, the Southwestern, Northwestern and the Eastern terranes, whose structure, sedimentary record and tectonothermal evolution differ from each other. The terranes are separated by major N-trending high-angle faults. Their juxtaposition probably occurred during the Caledonian orogeny, though no consensus about the involved mechanisms yet exists.
Petrological (P-T-t), structural and geochronological investigations have been taking place for many years in logistic combination with the geological mapping programme, and are now concentrated in Ny-Friesland, the western part of the Eastern terrane. The basement rocks of Ny-Friesland is divided into five thrust sheets; the Finlandveggen, Rekvika, Nordbreen, Dirksodden and Mosselhalvøya nappes. The first four nappes are composed of ca. 1750 Ma old granites and granitic gneisses which are overlain by younger, amphibolite facies metasediments.
The structure of Ny-Friesland is dominated by the ca. 150 km long, N-S-trending Atomfjella antiform. The antiform is characterized by a conspicuous N-S trending ductile fabric with axis-parallell extension. Early isoclinal folds and related thrusts have been refolded by the Atomfjella antiform. The early fabrics have been overprinted by younger N-S trending extensional structures, leaving little structural evidences, such as shear-sense indicators, for the direction of thrusting of the nappes.
Deltakere
Prosjektleder: Synnøve Elvevold
Øvrige deltakere: Winfried Dallmann
Samarbeidspartnere
- PMGRE (Polar Marine Geological Research Expedition) St. Petersburg
- Universitetet i Oslo