| Summary: | This study investigates the upper-mantle P- and S-wave velocity structure as well as structure in the VP/VS ratio across the high topography areas of north Atlantic Caledonides, integrating data from a new East Greenland Caledonide Central Fjord Array (EGCFA) with results of recent studies of the northern Tornquist Zone and Southern Scandinavia, the Caledonides in central Norway and the Scandinavian Peninsula. On the European side of the Atlantic a strong Upper-Mantle Velocity Boundary is traced from the Tornquist zone, past the Oslo Graben, along the western boundary of the Transscandinavian Igneous Belt and further north along the Norwegian coast. This boundary stands out clearly in the P-velocity and even clearer in the S-velocity. Compositional difference between the Baltic Shield and adjacent units is indicated by consistent VP/VS ratio anomalies. The new EGCFA profile reveals a similar strong upper-mantle velocity boundary under the East Greenland Caledonides. However, the contrast in the VP/VS ratio is not as clear at this location. A correlation study of topography versus upper-mantle velocity revealed positive correlation in southern Norway but negative or absent correlation in three other regions bordering the North Atlantic. This result challenges the hypothesis of widespread Late Cenozoic uplift in this region.
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