Three-phased latest Jurassic–Eocene rifting and mild mid-Cenozoic compression offshore NE Greenland

Abstract

The groundwork for the northeast Atlantic opening was laid during the latest Jurassic to mid-Cenozoic. The period is well-investigated on the Norwegian and UK continental margins at which the tremendous petroleum potential to a large extent resulted from the latest Jurassic to mid-Cenozoic development. Harsh ice conditions have made investigations of the NE Greenlandic margin more difficult. Based on a large 2D seismic dataset tied to cored stratigraphic boreholes, three phases of rifting leading to continental breakup are documented: 1) latest Jurassic to mid-Cretaceous, 2) mid-Cretaceous to Maastrichtian and 3) Maastrichtian to early Eocene. This development is in many ways comparable to offshore Norway. However, Early Cretaceous rifting was more severe offshore NE Greenland compared to elsewhere in the northeastern Atlantic with more than 10 km downfaulting and accumulation of up to 16 km of Lower Cretaceous strata in the Danmarkshavn and Thetis basins. During the mid-Cretaceous, rifting ceased in most of the Danmarkshavn Basin and the inner Thetis Basin but continued in the outer Thetis Basin. This coincides with a shift in rifting taking place in the Barents Sea, offshore central Norway, and onshore NE Greenland.During the latest Cretaceous, rifting shifted seawards to the outermost NE Greenland margin and the eventual line of continental break-up, again mirroring the development at the central Norwegian margin. Coincident uplift of Greenland resulted in clinoform progradation across the central and southern Danmarkshavn Basin and incursion of Greenland-derived sand to offshore central Norway. The uplift and change in rifting may reflect the initial effects of the Icelandic mantle plume building up underneath Greenland. Shortly thereafter, magmatism commenced along parts of the NE Greenland margin followed by continental break-up. Subsequently, small amounts of compression on the outer margin formed subtle folds and small thrusts during presumably Oligocene to early Miocene times.