Timing and mechanisms of North Atlantic Cenozoic uplift: evidence for mantle upwelling

Abstract

AbstractPostrift domal uplift patterns are a distinct feature of northern North Atlantic margins. On the basis of apatite fission-track data, offshore seismic stratigraphy, geomorphology, gravity and seismic tomography, we argue that southern Norway is characterized by predominantly Neogene domal uplift. The uplift is tectonically driven and estimated at around 1.5 km. Low flexural rigidity (c. 1022 N m) and corresponding equivalent elastic thickness Te (c. 15 km) values for the southern Norwegian lithosphere indicate that the lithosphere is relatively weak. Additionally, high temperature estimates derived from low-velocity mantle P- and S-wave seismic tomography below the dome suggest a thermal anomaly at depth. Therefore, the observed topography is most plausibly explained by mantle upwelling. This would supercede other previously proposed primary mechanisms such as eustasy, isostatic readjustment to glacial erosion, magmatic underplating and intraplate compression. Currently available data suggest similar processes for other uplifted regions such as Spitsbergen, northern Norway, the British Isles and parts of East Greenland.