Comment on: “Cenozoic evolution of the eastern Danish North Sea” by M. Huuse, H. Lykke-Andersen and O. Michelsen, [Marine Geology 177, 243–269

Abstract

Neogene uplift and erosion of the southern part of the Scandinavian Shield and adjoining areas have been revealed by several studies during the last 10 yr. The amount of late Cenozoic erosion induced by the Neogene uplift and subsequent glacial processes that has been estimated in some of these studies has, however, been questioned in a recent paper by Huuse et al. (2001). Huuse et al. (2001) estimated late Cenozoic erosion from stratal geometries along a N^S oriented seismic section west of Jylland, Denmark (Figs. 1 and 2). These authors found erosion to be several hundred metres less than estimated in studies of maximum burial based on vitrinite re£ectance and sonic data (Jensen and Schmidt, 1993; Japsen, 1998). We ¢nd, however, that the preserved late Cenozoic record in the eastern North Sea is in good agreement with the section removed by the late erosional event as estimated by basin modelling and sonic data (Japsen and Bidstrup, 1999). According to our interpretation, a section of ca. 400 m westward dipping, upper Miocene sediments is erosionally truncated along an E^W oriented seismic dip-line that intersects the strike-line published by Huuse et al. (2001) (Fig. 3). Eastwards extrapolation of this upper Miocene unit ¢ts with the estimates of the section removed by erosion based on data in wells where mid-Miocene sediments are preserved. Consequently, ca. 400 m of upper Miocene sediments appear to have been deposited in the easternmost North Sea Basin and then removed by erosion, e.g. during the Plio^Pleistocene. Closer to the Scandinavian Shield, where the base-Quaternary unconformity cuts into Paleogene and older strata, an earlier phase of Neogene uplift and erosion also appears to have taken place, e.g. during the midMiocene (Japsen et al., in press). Japsen and Bidstrup (1999) studied maximum burial of the drilled section in 68 Danish wells in order to estimate the amount of section missing due to late Cenozoic erosion. This they found to be smaller than that estimated in previous studies. The study was based on basin modelling constrained by e.g. vitrinite re£ectance data and by sonic data from diierent stratigraphic units. These authors found the thickness of the missing section to increase towards the coasts of Norway and Sweden from zero in the North Sea to ca. 500 m in most of the Danish Basin, but over a narrow zone it was found to reach ca. 1000 m on the Skagerrak^Kattegat Platform. The increasing amount of erosion matches the increase in the hiatus at the base of the Quaternary where Neogene and older strata are truncated, and the Mesozoic succession is thus found to have been more deeply buried by ca. 500 Paleocene^Miocene sediments in large parts of the area. On the basis of