Late Mesozoic-Cenozoic Evolution of the NE Atlantic Region and Links to the Arctic

Detailed studies of the continental margins off Norway, Greenland and the Barents Sea have revealed a series of Late Mesozoic-Cenozoic rift phases reflecting the main plate tectonic episodes in the North Atlantic-Arctic breakup of Pangea. Each rift phase is related to the northward propagation of North Atlantic sea floor spreading, which finally reached the incipient Norwegian-Greenland Sea in early Tertiary times, but they are also linked to important tectonic events in the Arctic. Late Jurassic-Early Cretaceous rifting was a dominant, composite tectonic episode which gave rise to prominent NE-trending structures in the NE Atlantic. Following rifting, a wide region subsided and was covered by thick Cretaceous strata. Aptian-?Albian rifting is documented locally off Mid-Norway, onshore East Greenland and in the SW Barents Sea. A Large Igneous Province developed in the Arctic during Early Cretaceous breakup of the Amerasia Basin and formation of the Alpha Ridge, and gave rise to widespread magmatism in the northern Barents Sea. We propose that the SW Barents Sea rift may have a component trending northwards east of Svalbard, but this may be masked to some extent by the extensive magmatism which caused regional uplift instead of subsidence. A distinct Late Cretaceous rift event, with onset in middle Campanian, is documented on the conjugate mid-Norway and East Greenland continental margins, and is characterised by large-scale normal faulting and locally by low-angle detachment faulting within thick Cretaceous strata. The Late Cretaceous rifting between Norway and Greenland was taken up within the De Geer Zone by down-faulting in a pull-apart setting. The rifting culminated in crustal breakup and accretion of oceanic crust near the Paleocene-Eocene transition, accompanied by large-scale igneous activity associated with the North Atlantic Large Igneous Province. Passive rifted margins developed off mid-Norway and central East Greenland, and along the northern Barents Sea during opening of the Norwegian-Greenland Sea and Eurasia Basin, respectively. The western Barents Sea-Svalbard and NE Greenland margins developed as predominantly sheared margins. There is a well-defined along-strike margin segmentation and the various segments are characterized by distinct crustal properties, structural and magmatic styles, and post-opening history of vertical motion. The continent-ocean transition is confined within a narrow zone at the sheared margin segments, but is more obscure and partly masked by volcanics at the rifted margin segments. Following breakup, the subsiding margins experienced modest sedimentation until the late Pliocene when large wedges of glacial sediments prograded into the deep ocean from uplifted areas along the continental margins.