Evidence for Late Triassic provenance areas and Early Jurassic sediment supply turnover in the Barents Sea Basin of northern Pangea

• Published in: Lithosphere
• Main Authors: Klausen, T. G., Müller, R., Sláma, J. (Jiří), Helland-Hansen, W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: U-Pb geochronology; detrial zircon; Cenozoic evolution; rocks; metamorphism; Barents Sea; Nordmela; Novaya Zemlya
• Online Access: https://doi.org/10.1130/L556.1; http://hdl.handle.net/11104/0282086

We used detrital zircon fractions from the Late Triassic to Early Jurassic sedimentary succession in the Norwegian Barents Sea to constrain the role of eastern provenance areas in the basin infill history of the Northern Pangea Boreal basin. Geochronological data from sedimentary rocks in this succession reveal detrital zircon ages that are very close to the biostratigraphically defined maximum depositional age of the two lowermost intervals: The Norian to Rhaetian Fruholmen Formation show U-Pb minimum ages of 208.3 +/- 4.2 Ma (discordant by - 0.58) and 213.8 +/- 5 Ma (discordant by 0.8), and the Rhaetian to Sinemurian Tubaen Formation is 200.6 +/- 4.9 Ma (discordant by -3.99) at its minimum. These are the youngest ages thus far documented in the Norwegian Barents Sea, and they demonstrate that a provenance area was magmatically active while, or shortly before, these formations were being deposited. Such protolith ages have not been documented close to the study area, but based on the regional tectonic setting and paleogeography, we argue that the Novaya Zemlya protrusion of the northern Uralian orogen was the most likely provenance area in the region. The Sinemurian to Pliensbachian Nordmela Formation samples yielded, with an exception of a single detrital zircon age of 211 +/- 4.3 Ma, a consistent 240-237 Ma minimum detrital zircon age, which suggests that either the magmatic activity or the sediment supply had come to an end by Sinemurian times. This turnover can be explained by a change in the hinterland drainage pattern. This study documents that eastern provenance areas were actively supplying sediments into the Norwegian Barents Sea Basin later than previously assumed, and our data offer age constraints for tectonic activity in the basin and its hinterland inferred from the changes in sediment supply to the basin.