North Atlantic marine rifting in the Early Triassic: new evidence from East Greenland

Abstract

Two Early Triassic marine rifting events have been recognized in new outcrop data from East Greenland, increasing our understanding of this important tectonic episode in the development of the NE Atlantic (Norwegian–Greenland Sea). A detailed ammonoid stratigraphy, together with stratigraphic and radiometric evidence, show that the first rifting event took place in the Early Griesbachian. This event was largely confined to major basin-margin faults. The second rifting event, which involved splay-faulting and intra-basinal fault-block tilt, is dated as late Griesbachian. Deposition in East Greenland took place in half-grabens dominated by deep-water gravity flow sandstones and mudstones as well as shallow marine conglomerates and sandstones. Similarly, recent core data from offshore Mid-Norway show that deposition on the eastern margin of the Norwegian–Greenland Sea took place in deep marine settings dominated by gravity flows. This suggests that the Early Triassic marine realm extended from East Greenland to the present-day Norwegian coastline and that the marine rift-basin was significantly wider than previously thought.