Episodes of sea-floor spreading recorded by the North Atlantic basement

Sites 403 and 404

“…In the final phase, rifting and volcanism around 60 m.y. was followed by spreading at about the incipient Reykjanes Ridge axis at 52 m.y., thus completing the isolation of the Rockall Plateau micro-continent (Vogt et al, 1971;Laughton, 1971;Vogt and Avery, 1974;Roberts, 1975). Spreading continued in the Labrador Sea until about 40 m.y.…”

“…in age (Ewing and Ewing, 1958;Godby et al, 1968;Vogt et al, 1969Vogt et al, , 1971Scrutton and Roberts, 1971;Ruddiman, 1972;Laughton, 1971;Vogt and Avery, 1974) (Figure 3). The age of the oceanic basement abutting the southwest margin is, by the position there of anomaly-32, 73 m.y.…”

“…This spreading phase, of unknown speed and duration, split off the GreenlandRockall-North American plate from Eurasia. By 73 m.y., spreading had ceased in the Rockall Trough and the axis shifted to the line of the Labrador Sea, spreading Greenland-Rockall away from North America and creating the Gibbs fracture zone (Vogt et al, 1971;Laughton, 1971;Le Pichon et al, 1972;Olivet et al, 1974;Roberts, 1975). In the final phase, rifting and volcanism around 60 m.y.…”

“…The age of the oceanic basement abutting the southwest margin is, by the position there of anomaly-32, 73 m.y. (Vogt et al, 1971;Laughton, 1971;Vogt and Avery, 1975;Jones and Roberts, 1975). Early Cretaceous oceanic crust has been inferred to underlie the Rockall Trough (Roberts, 1971;Scrutton and Roberts, 1971;Roberts, 1974Roberts, , 1975Jones and Roberts, 1975).…”

“…Synthesis of the plate tectonic history of the North Atlantic Ocean, based on these data, has demonstrated that three distinct phases of spreading structurally isolated the Rockall Plateau (Vogt et al, 1971;Le Pichon et al, 1972;Laughton, Berggren et al, 1971;Olivet et al, 1973;Roberts, 1975). The first phase, in Early-Middle Cretaceous time, may have contemporaneously opened the Rockall Trough and Bay of Biscay and was preceded by a rifting phase perhaps represented by the Cimmerian epeirogeny of northwest Europe (Roberts, 1971(Roberts, , 1975Roberts et al, 1973;Jones and Roberts, 1975).…”