Svalbard is pivotal for defining the northern extent of the Grenville/Sveconorwegian orogenic belt. Consequently, to constrain the origin of Svalbard's Northwestern Terrane (NWT), detrital zircon populations from samples of the Krossfjorden Group and Smerenburgfjorden complex, northwestern Svalbard, were analyzed by U-Pb Laser ablation ICP-MS. These data indicate that the NWT's metasedimentary basement, the Krossfjorden Group, was deposited between c. 1020 and 995 Ma and indicates that the Smerenburgfjorden complex may represent a migmatized and deformed part of the Krossfjorden Group. Statistically, the source area of the Krossfjorden Group cannot be distinguished from other late Mesoproterozoic to early Neoproterozoic siliciclastic sequences exposed in the Caledonian orogenic belt and their detrital populations are compatible with derivation from the Eastern Grenville Province (EGP), dominated by ages coinciding with the Labradorian event (1710-1600 Ma). The diachronous tectonothermal evolution of these Meso- to Neoproterozoic metasedimentary sequences suggests deposition in a spatially linked peripheral foreland and remnant ocean basins outboard of the EGP, which migrated eastwards during the final suturing of Rodina. Thus, they do not represent a northern branch of the Grenvillian/Sveconorwegian orogeny.
- Programområde 4: Mineralske råstoffer