Upper Cretaceous palaeogeography of the British Isles and adjacent areas

The Upper Cretaceous sub-Period saw the deposition of the Chalk over much of the British Isles region, with progressively inundated land areas. By the Late Maastrichtian land areas were at their minimum and a thick Chalk sequence accumulated over the region. In the Early Palaeocene uplift in the Irish Sea interrupted deposition, but in many areas marly chalk deposition resumed. Mid-Palaeocene uplift led to dramatic erosion of this cover so that in most places all the Danian, Maastrichtian and, in some places, Campanian and even Santonian Chalk were removed before deposition of Late Palaeocene sediments; this widespread and pervasive erosional event has masked the true extent of Maastrichtian deposition. In areas outside the Palaeocene basins erosion of the Chalk continued, rapidly exposing underlying rocks.