Isostatic compensation of Quaternary vertical crustal motions: coupling between uplift of Britain and subsidence beneath the North Sea

TLDR: In this article, it was shown that the Quaternary uplift of Britain and subsidence beneath the North Sea are coupled, mediated by lower-crustal flow induced by the lateral pressure gradient caused by climate-driven surface processes.

Abstract: New data from offshore and onshore regions confirm the view that the Quaternary uplift of Britain and subsidence beneath the North Sea are coupled, mediated by lower-crustal flow induced by the lateral pressure gradient caused by climate-driven surface processes. Most measured onshore uplift rates, in both upland and lowland localities, are only applicable since the Mid-Pleistocene Revolution; beforehand, generally lower rates prevailed. Earlier (?Oligocene–Pliocene) phases of uplift and subsidence had typically even lower rates; furthermore, the western margin of the North Sea depocentre was ∼200 km farther from the modern coastline of north-east England. In the earliest Cenozoic, complex isostatic adjustments occurred in response to the magmatism associated with the Iceland mantle plume; the contemporaneous land surface (relative to the present-day rock column) in northern England was typically ∼1500 m OD. However, this activity died out during the Palaeogene; the main effect of these events on the modern isostatic configuration was via the emplacement of thick mafic underplating, which now constricts the mobile lower-crustal layer, explaining the Late Cenozoic ultra-stability of Ireland. The evidence enables interpretations of the present-day topography of Britain as static, caused by the Iceland mantle plume, or actively developing in response to plate motions or plate boundary forces, to be excluded.