Prolonged dynamic support from the Icelandic plume of the NE Atlantic margin

Abstract

Sedimentary basins affected by hotspots often contain records of uplift and subsidence within coeval stratigraphic successions. The subsidence history can contain measurable perturbations in ancient palaeogeographies that can help constrain the duration of dynamic support. At c. 56 Ma the NE Atlantic experienced uplift related to the Iceland mantle plume. Within the Faroe–Shetland Basin, we document the stratigraphic record of subsidence following plume uplift, through integration of regional seismic datasets and well data. Subsidence following plume uplift is recorded by mapping the southward migration of palaeocoastlines throughout the early Eocene of the Faroe–Shetland Basin. We find that after initial uplift over 0.5 myr, subsidence was inhibited for 0.45 myr. Coeval with initiation of rifting in the North Atlantic, at 54.9 Ma, a c. 0.9 myr period of accelerated subsidence occurred, recorded by migration of the coastline by c. 80 km inland. We attribute these events to a prolonged period (2 myr) of dynamic support from the Iceland plume terminated by rapid loss of dynamic support coeval with rifting in the NE Atlantic at 54.9 Ma. Our results suggest that palaeogeographical analysis is a powerful tool in constraining the duration of dynamic support in basins affected by mantle plumes.