A sedimentary provenance study of modern river sands from northern Fennoscandia and its insight into the source of Mesozoic successions deposited on the southwest Barents Shelf.

A series of sedimentary provenance techniques were applied to 20 modern sand samples collected from twelve major river catchments in northern Fennoscandia. This was carried out in order to evaluate the extent that Mesozoic successions deposited on the southwest Barents Shelf were sourced from northern Fennoscandia.

One of the most distinctive provenance signatures in northern Fennoscandia comes from samples collected along the Tana River, which traverses the Lapland Granulite Belt (LGB). Downstream of exposures of the LGB, modern sands are dominated by rutile with c. 1.9 Ga U-Pb ages and a chemistry which indicate crystallization at c. 850 °C from a pelitic protolith. A rutile signature similar to the Tana River detritus is replicated in the Late Triassic – Early Jurassic Realgrunnen Subgroup deposited in the vicinity of the Nordkapp Basin, and indicates a common origin from the LGB. A strikingly different pattern comes from the Realgrunnen Subgroup deposited in the Hammerfest Basin where rutiles are mostly c. 430-515 Ma and crystallised at c. 650 °C from a pelitic protolith. The similarity of this pattern to rutile data collected from the Målselva River modern sands indicate a source from Caledonian allochthons affected by Palaeozoic amphibolite-facies metamorphism.

Models depicting rejuvenation of a Fennoscandian sedimentary source region and Late Triassic drainage reorganisation are supported by these data. The rutile technique provides one of the clearest mechanisms for tracing the dispersal of Fennoscandian-derived sediment across the Barents Shelf.