Basin Development of the West Greenland Margin during the Late Cretaceous Continental Break-up

Sulaiman Alsulami

Syn and post-rift sedimentation, differential subsidence and uplift have been established for the west Greenland margin through time. The study presents a structural analysis of the tectonic development of the west Greenland margin. This study utilized GEUS and TGS 2D seismic reflection data to evaluate the lateral variation of megasequences and the crustal thinning factor associated with the evolution of the margin. The megasequences have been correlated along the entire west Greenland margin even though it is subdivided into four district provinces, each containing sub-basins. Isochron maps were used to identify thickness variations, to delineate areas affected by faulting and to establish overall basin architecture. In addition, the crustal thinning factor (β) was estimated for three representative seismic profiles: 1) Labrador Sea; 2) Davis Strait; and 3) Baffin Bay. The southernmost Cape Farewell Province requires a whole lithosphere thinning factor β ~1.6 to infinity and upper crust β of ~1.2. The Nuuk West Province towards the north is characterised by a significant number of small rift basins and domes associated with uplift, erosion, inversion and strike deformation structures from the Fylla Complex Structures in the south to Sisimiut Basin to the north. In contrast to this, a volcanic centre dominates the Disko West Province and the rift architecture is poorly imaged. Upper crust stretching of β ~1.1 was common with a gradual increase of the whole lithosphere β from ~1.5 to infinity. The volcanic rocks become less prevalent in Baffin Bay where the whole lithosphere crustal thinning factor β ranges from ~2.1 to ~5 (particularly evident in the Melville Bay Graben and the Kivioq Basin) and the upper crustal stretching factor β is ~1.4. Consequently, a variation in late Cretaceous lateral sediments is observed in the syn rift packages of the Fylla Structures Complex. The presence of post rift sediments in the Lady Franklin Basin may also indicate subsidence relative to the Fylla Structures Complex. The Davis Strait flower-like structure is a transfer zone during rifting and may have caused a shift in the position of the depocentre to be south of Baffin Bay. In summary, our analysis reveals that the stretching factor (β) derived from faulting of the upper crust (~1.1 to 1.4) is less than the stretching factor (β) from the whole lithosphere (~1.5 to >10) and therefore a depth-dependent stretching model is preferred for the west Greenland margin.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013