Plate-kinematic reconstructions of the North Atlantic and Arctic: Late Jurassic to Present

Abstract Numerous reconstructions of the North Atlantic have been proposed based on fitting of magnetic anomalies transform-fracture-zone systems, continent-ocean boundaries, and/or bathymetry of previously adjacent segments of lithosphere. Some of the reconstructions have been used interpret the tectonic evolution of the Arctic, but none have used constraints from the geology of the Arctic to test the viability of the proposed reconstructions. The evolution of the circum-North Atlantic region is dominated by the relative motion history of North America and Eurasia, and by smaller plates, including Greenland, Rockall, Hatton-Edoras, Svalbard, Jan Mayen. Lomonosov and North Slope-Chukotka. Seafloor spreading began between North America and Eurasia in the Middle Albian, approximately 110 m.y. ago. Post-110 m.y. relative motions between North America and Eurasia are limited by the unconformable overlap of the essentially undeformed Aptian (?)-Albian and younger Okhotsk-Chukotsk volcanic-plutonic belt across the South Anyuy suture linking the North Slope-Chukotka block to Eurasia, and by the absence of post-Early Cretaceous motion between the North Slope-Chukotka block and North America. This constraint is supported by the geology of the circum-Arctic shelf which is characterized by extensional and strike-slip basins, but lacks any evidence of Middle Mesozoic and younger structures associated with contractional deformation. Published reconstructions of the North Atlantic predict between 500 and 1400 km of E-W shortening of North America to Eurasia during the interval 110-56 Ma. This is clearly incompatible with the geology of the Arctic, and suggests that all of these reconstructions are incorrect and therefore analyses dependent on these reconstructions, such as the evolution of the Tethyan domain, global paleomagnetic inversions, and paleo-oceanic and paleoclimatological reconstructions must also have significant errors. We present a revised set of plate reconstructions of the North Atlantic and Arctic that are compatible with constraints imposed by the geology, requiring less than 25 km of E-W shortening between 110 and 56 Ma by accounting for the distribution and timing of intracontinental extension along various margins of the North Atlantic and Arctic. Our revised reconstructions incorporate: 1. (1) The Amerasian Basin being opened by anticlockwise rotation of the North Slope-Chukotka block away from the Canadian Arctic islands between ≈ 131 and ≈ 110 Ma 2. (2) the Lomonosov Ridge being attached to the North American plate since 80 Ma opening the Eurasian Basin as a propagating rift 3. (3) initiation of seafloor spreading within the Labrador Sea at ≈ 90 Ma, continuing until chron 7 time and preceded by continental extension that started during the Barremian 4. (4) sinistral transtensional rotation of Svalbard + Greenland + Hatton-Edoras Bank + Rockall Plateau + North America away from Eurasia during the Late Jurassic and Early Cretaceous, which gave rise to abundant extensional basins along the conjugate margins; and 5. (5) anticlockwise rotation of Greenland ± Hatton-Edoras Bank ± Rockall Plateau away from the Eurasian margin to successively open the Rockall Trough, Rockall-Hatton Trough, and the North Atlantic between 110 and 84 Ma. ≈ 90 and ≈ 60 Ma, and ≈ 59 Ma and the present, respectively.