Fridtjof Riis

Quantification of Cenozoic vertical movements of Scandinavia by correlation of morphological surfaces with offshore data

Abstract Correlation between offshore geology and onshore morphological elements suggests that the enveloping summit level of Scandinavia originated as a peneplain in the Jurassic. Deep weathering profiles locally encountered in the mountainous areas are interpreted as relics of Mesozoic denudation. Late Cretaceous and Early Tertiary uplift of northern and western Fennoscandia caused deep erosion, and an erosional surface which marks a lower level of elevation was formed in the east. In northern Fennoscandia, this erosional surface was transgressed in the Eocene, and its present elevation is a result of uplift in the Neogene. The recognition of the Mesozoic peneplain and the Tertiary erosional surface has allowed a quantification of the two major phases of Cenozoic uplift. The Paleogene uplift phase had a maximum of almost 1500 m in northern Scandinavia, while the Neogene phase had its uplift centra in South Norway and Lofoten which were uplifted approximately 1000 m. The corresponding Neogene erosion of the coastal areas is estimated to have reached a maximum of 800–1000 m along the coast of southern Norway and slightly more to the north.

Chronology of Tertiary fan deposits off the western Barents Sea: Implications for the uplift and erosion history of the Barents Shelf

Abstract A combined biostratigraphic and seismic study was performed on three holes drilled in the western Barents Sea. Two holes penetrate the thick sedimentary wedge which forms a large fan located off a trough on the Barents Sea Shelf, the Bjornoyrenna Fan. The study shows that the fan was built over a short time span in the late Pliocene-Pleistocene, mainly due to glacial erosion of the Barents Shelf region. This contrasts earlier age assignments which concluded that fan-deposition started in the Oligocene. The results have a major impact on the understanding of trough mouth fan formation and has important bearing on the history of the sedimentary basins of the Barents Shelf.

Evolution of the Triassic shelf in the northern Barents Sea region

The interpretation of an unpublished data set of shallow stratigraphic cores and deep, seismic profiles from the northern Barents Shelf has provided new information about the Middle and Late Triassic development of the Barents Shelf and Svalbard. At that time, sediment sources along the eastern and south-eastern margins of the Barents Sea controlled the infilling of a previously deeper shelf area, gradually converting it into a paralic platform. Compared with the eastern source, sediment volumes from other areas were small. In our data, there are no indications of a provenance area north of Svalbard. Progradation from the ESE resulted in diachronous lithostratigraphic boundaries. The organic-rich shales of the Botneheia and Steinkobbe formations were deposited in the remaining deeper shelf areas in the western and north-western Barents Sea shelf, from the Olenekian to the latest Ladinian, by which time the progradation from the ESE had reached eastern Svalbard. In mid-Carnian times, the area of paralic deposits extended from the eastern Barents Sea into the Svalbard Archipelago.