Structural and Thermal Evolution of the SE-Baffin Bay Margin: Insight from the West Greenland Area

Mohamed Mansour Abdelmalak

We present a structural and thermal synthesis of the Cretaceous-Paleocene sedimentary basin of the central West-Greenland margin. This margin is located immediately to the north of the Ungava transform zone linking the Labrador Sea to Baffin Bay. Its structural and thermal evolution are made complex by the large mantle melting occurring during the Paleogene and the consecutive development of a volcanic passive margin. The structural evolution of the margin was characterized by: (1) a first syn-depositional extensional episode which took place during Aptian?/Albian. This early tectonic event is consistent with a NNE-SSW extensional direction. The basement inheritance probably exerts a structural control on this deformation. This episode is tentatively interpreted as a RRR triple junction during Lower Cretaceous; (2) A post-rift subsidence episode which occurred during the Cenomanian/Campanian period with a small scale sag basin formation. The NW-SE to WNW-ESE oriented depocenters follow the former trends of the previous syn-sedimentary faults; (3) a late syn-sedimentary extension episode which occurred during the Upper Campanian to Early Paleocene period. The faults associated with this last extension are the border faults of the present day sedimentary basins. This stage predates the extrusion of Paleocene hyaloclastites in a residual lacustrine basin. The syn-magmatic Eocene breakup is notably accommodated with the development of the SDR (Seaward Dipping Reflectors) sequences to the western edge of the exposed margin. Within the sedimentary basin, the Tertiary extension is poorly expressed. The thermal maturity of sediments was inferred using the routine methods (RockEval and vitrinite reflectance). The new thermal results combined to the published data outline that maturity of the sedimentary formations increase seaward (i.e. toward the SDRs) whereas the sediments are younger. Taking together both structural and thermal data, it appears that the sedimentary basin was probably affected by high thermal fluxes to the west. We discuss the significance of this anomalously thermal gradient regarding to the development of the magmatic part of the margin. Some local effects caused by sill/dykes intrusion are also noticed in the sedimentary basin.

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