Alpine ocean seafloor spreading and onset of pelagic sedimentation : new radiolarian data from the Chenaillet-Montgenèvre ophiolite (French-Italian Alps)
is older than those previously established on ophiolite sedimentary covers from this segment of the western Alps. This chronological relationship implies either a late seafloor spreading-related magmatic activity in places younger than adjacent initial
pelagic sedimentation, or more likely that the Lago Nero-Replatte and the Chenaillet s.s. thrust sheets are distinct and distant pieces of lithosphere. These results strengthen the Bathonian correlation of widespread seafloor spreading in both western
Zur methodischen Vertiefung und Weiterentwicklung der Grundidee Alfred Wegeners: sea-floor-spreading und Neue Globaltektonik. (Approfondissement méthodique et développement des idées d'Alfred Wegener: expansion des fonds océaniques et tectonique
sequence. They were part of a Tethyan area of deposition now widely dispersed in North America, New Zealand, and Southeast Asia by subsequent sea-floorspreading and accretion onto the continents bordering the Paleo-Pacific.
Atlantic Ocean ; Bathymetry ; Geophysics ; Global tectonics ; Island arc ; Magnetic anomaly ; Oceanic ridge ; Plate tectonics ; Sea current ; Seafloor;Ocean floor ; South Atlantic Ocean ; Submarine geomorphology ; Submarine valley
Morphostructural transformation and stages of the geological history of the Scotia Sea were studied in connection with spreading of the Mid-Scotia Ridge, which has undergone a series of evolutionary cycles during the movement of the ancient South
-American and Antarctic lithospheric plates and young Scotia plate. The opening of the Scotia Sea (South Antillean basin) had taken place at 30-31 m.y. ago; the Drake Strait―at 20-23 m.y. At the same time the Antarctic Circumpolar Current―the dominant
basin, its bordering ridges and Mid-Scotia Ridge. One more ridge of mid-oceanic type was created in eastern part of the Scotia Sea about 7 m.y. ago (Late Miocene). Some new transform faults were discovered. A new morphostructural map of South-West
Atlantic Ocean and Scotia Sea was compiled. - (L'A.).