Torben Bidstrup

Neogene uplift and erosion of southern Scandinavia induced by the rise of the South Swedish Dome

Abstract Basin modelling and compaction studies based on sonic data from the Mesozoic succession in 68 Danish wells were used to estimate the amount of section missing due to late Cenozoic erosion. The missing section increases gradually towards the coasts of Norway and Sweden from zero in the North Sea to c. 500 m in most of the Danish Basin, but over a narrow zone it reaches c. 1000 m on the Skagerrak-Kattegat Platform in northernmost Denmark. 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 c. 500 Paleocene-Miocene sediments in large parts of the area. These observations suggest that the onset of erosion occurred during the Neogene, and that the Skagerrak-Kattegat Platform was affected by tectonic movements prior to glacial erosion. In southern Sweden just east of the Kattegat, the exposed basement of the South Swedish Dome attains altitudes of almost 400 m. The formation of the Dome started in the Late Palaeozoic, but geomorphological investigations have led to the conclusion that a rise of the Dome occurred during the Cenozoic. We find that the pattern of late Cenozoic erosion in Denmark agrees with a Neogene uplift of the South Swedish Dome and of the Southern Scandes in Norway. This suggestion is consistent with major shifts in sediment transport directions during the late Cenozoic observed in the eastern North Sea, and with formation of a new erosion surface as well as re-exposure of sub-Cambrian and sub-Cretaceous surfaces in southern Sweden. The Neogene uplift and erosion of southern Scandinavia appears to have been initiated in two phases, an early phase of ?Miocene age and a better-constrained later phase that began in the Pliocene. Neogene uplift of the South Swedish Dome with adjoining areas in Denmark fits into a pattern of late Cenozoic vertical movements around the North Atlantic.

Denudation and uplift history of the Jameson Land basin, East Greenland—constrained from maturity and apatite fission track data

Abstract The Jameson Land basin in East Greenland comprises a well exposed succession of Upper Paleozoic–Mesozoic sediments. During Middle Devonian–Early Permian rifting, ∼13 km of continental clastics were deposited. In latest Paleozoic to Mesozoic times, ∼4 km of sediments accumulated during regional subsidence. In the Early Paleocene, during North Atlantic break-up, the basin was covered by a thick volcanic pile. Subsequently, uplift and erosion took place over the whole region. The volcanic cover was completely removed from Jameson Land and erosion cut deeply into the underlying sediments. To assess the exploration potential of Jameson Land, a basin modelling study with 21 1D pseudo-wells was carried out based on all seismic and surface data available. In addition to the calculation of hydrocarbon generation in space and time, the basin modelling provided an opportunity to study the magnitude and timing of uplift and erosion. Basin modelling constrained by apatite fission track data has made it possible to determine a consistent uplift and erosion history of the area. Tectonic backstripping based on a simple Airy type isostatic model has been used to separate the tectonic uplift from the actual uplift. The combined basin modelling and backstripping study has led to the following conclusions: (1) the thickness of the Cretaceous succession varied from 1.3 km in the south to 0.3 km in the north; (2) the volcanic rocks formed a wedge with a thickness of >2 km in the south thinning to

Chapter 43 Assessment of NE Greenland: prototype for development of Circum-Arctic Resource Appraisal methodology

Abstract Geological features of NE Greenland suggest large petroleum potential, as well as high uncertainty and risk. The area was the prototype for development of methodology used in the US Geological Survey (USGS) Circum-Arctic Resource Appraisal (CARA), and was the first area evaluated. In collaboration with the Geological Survey of Denmark and Greenland (GEUS), eight ‘assessment units’ (AU) were defined, six of which were probabilistically assessed. The most prospective areas are offshore in the Danmarkshavn Basin. This study supersedes a previous USGS assessment, from which it differs in several important respects: oil estimates are reduced and natural gas estimates are increased to reflect revised understanding of offshore geology. Despite the reduced estimates, the CARA indicates that NE Greenland may be an important future petroleum province.

Comment on: ''Cenozoic evolution of the eastern Danish North Sea'' by M. Huuse, H. Lykke-Andersen and O. Michelsen, (Marine Geology 177, 243^269)

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

Saline Aquifer Storage of CO2 from Major Point Sources — A Danish Case Study

Publisher Summary This chapter presents data for a possible future aquifer storage site in Denmark and evaluates the entire CO2 sequestration system including nature and characteristics of the geological structure, CO2 point sources, transport, and injection system. Over the past two years, the potential for underground storage of CO2 in Denmark has been evaluated as part of the European Community supported research project GESTCO (Geological storage of CO2 from fossil fuel combustion). The Danish part of the study comprised the storage potential of hydrocarbon fields, deep saline aquifers, and a combined application in geothermal energy systems. Two main options exist with respect to geological sequestration of CO2: utilization of CO2 for enhanced oil recovery (EOR) in the North Sea oil fields 500-100 km away from the emission points, and aquifer storage close to the individual emission point. The storage site comprises a 4-way domal structure with an estimated storage capacity of more than 1 Giga tons of CO2. It is situated close to the largest CO2 point source in Denmark. The analyzed sequestration system alone could account for up to half of the reduction required for Denmark to fulfill the Kyoto Protocol.

Geothermal Energy in Denmark – Potential, Policy and Progress

A new assessment of the geothermal resources in Denmark published by GEUS concludes that the Danish subsurface contains huge geothermal resources (Mathiesen et al. 2009). To rationalise administration the Danish Energy Agency (DEA) has established a new simple application procedure with a standard license period and work program. These initiatives and rising prizes on fossil fuels have together with public concerns related to climatic changes and increasing emission of CO2 to the atmosphere triggered the awareness of the large potential of the geothermal resources, which may contribute to a safe, sustainable, price stable and reliable supply of energy. It is thus expected that geothermal energy may play an important role in the future energy strategy in Denmark (Fenham et al. 2010; Nielsen et al. 2011).