The deep Møre and Vøring basins of the Norwegian Sea as basement highs prior to Late Jurassic rifting

Abstract

Prior to the Kimmeridgian-Tithonian climax stage of the Jurassic rift episode emergent basement occupied the area between deep sediment basins offshore Mid Norway and onshore East Greenland. The basement high was remnants of the mountain range that developed during the Late Silurian-Early Devonian final stage of the Caledonian Orogeny. The sediment basin offshore Mid Norway was built upon a crust involved in Caledonian continent-continent collision and crossed over the Laurentia-Baltica plate boundary. Drillhole observations demonstrate that Triassic, Lower and Middle Jurassic sediments entering basins from the west contain conglomerates and sandstones derived from the emergent landmass. Along western basin margins, beneath the southeastern Møre Basin and the Halten Terrace, the coarse-clastic sediments were deposited under fluvial, deltaic and marginal marine conditions and deltaic clinoforms are recorded in Jurassic sandstones on the western Halten Terrace. Basement essentially remained as positive topographic elements and an important source for sediments until late Middle Jurassic when basement was worn down and became insignificant as westerly source areas. Due to Late Jurassic rifting, eastern parts of the basement high were converted into hyperextended intracontinental rift basins later infilled by thick Cretaceous sediments, which gave rise to the deep and now 200 km-wide Møre and Vøring basins.

The evolution of catchment‐depositional system relationships on the dip slopes of intra‐rift basement highs: An example from the Frøya High, Mid‐Norwegian rifted margin

“…The Rogn Formation is a distinct sand unit that commonly sits stratigraphically within the Spekk Formation on the eastern flank of the Frøya High (Figure 2b,c, Chiarella et al, 2020). The Rogn Formation is typically interpreted to represent Late Jurassic—Early Cretaceous deposits of shoreface to offshore‐bar environments (Chiarella et al, 2020; Jones et al, 2021) in a narrow seaway between footwall block islands and the Late Jurassic coastline of the Norwegian mainland (Bunkholt et al, 2022; Chiarella et al, 2020; Faerseth, 2021). The Viking Group is capped by a regional unconformity, commonly referred to as the Base Cretaceous Unconformity (BCU), which is overlain by deposits of the mud‐prone Lyr and Lange formations of the Cromer Knoll Group.…”

“…However, the uplift and rotation of the backtilted footwall dip slope also offer accommodation for sedimentary systems fed by drainage directed away from the footwall crest. (Gawthorpe & Leeder, 2000;Muravchik et al, 2018;Rapozo et al, 2021;Ravnås & Steel, 1998;Smyrak-Sikora et al, 2018, 2021. The tectono-sedimentary setting of dip slopes developed along the footwall of major faults is considerably different to that of immediate hangingwall systems such as fault-scarp degradation-related fans or rift-margin deltas.…”