Tectonic Development of the North Atlantic: Revised Seafloor Spreading Isochrons and Tectonic Fabric Map from SEASAT Altimetry (Paleoceanographic Mapping Project, Progress Report No. 26-1287)
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New plate reconstructions for the opening of the North Atlantic were made by combining recent magnetic anomaly data and Seasat altimetry data. A tectonic fabric map of the North Atlantic from interpretation of Seasat data allowed us to trace the Charlie Gibbs Fracture Zone from the North American to the European margin. Ve use fracture zone lineations as additional constraints in fitting magnetic anomaly pairs by interactively using the advanced 3-D graphics capabilities of an Evans & Sutherland PS 300 computer system. We have applied a hierarchical analysis technique (Ross & Scotese, in press) to obtain a new set of reconstruction poles of relative motion for plates around the North Atlantic. Intraplate movements in the Canadian Arctic, in NE-Greenland, and the North Sea region were included in the model to improve the fit reconstruction and better describe propagating rift tectonics. Plate reorganizations at Chron 25 and 13 resulted in major changes of the plate boundary between Eurasia and North America in eastern Siberia and between Greenland and Svalbard. For the relative motion between Eurasia and North America in the Bering Sea region we suggest a succession of 4 tectonic phases from the Aptian to present day. Sinistral transpression dominated from chron MO (118.7 Ma) to chron 25. It was followed by dextral transtension from chron 25 to chron 13. Compression/left lateral transpression prevailed after chron 13. Our plate model predicts a Tertiary tectonic development between Greenland and Svalbard in four phases. We propose extension from chron 30 (68.4 Ma) to 25 (59.2), strike slip from chron 25 to 24 (56.1) and transpression from chron 24 to 20 (46.2 Ma) followed by transtension after chron 20.