GEUS Bulletin (Geological Survey of Denmark and Greenland)
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Structural development of Maglevandsfald: a key to understanding the glaciotectonic architecture of Møns Klint, SE Denmark
No full textThe Møns Klint Glaciotectonic Complex (Fig. 1) exposed in the N–S-trending chalk cliff on the east coast of the island of Møn in south-east Denmark is one of the most famous glaciotectonic geosites in the world. People of all nationalities are attracted to the site, which has more than 300 000 visitors per year. Many of them may not realise the uniqueness of the glaciotectonic framework, and are probably more fascinated by the spectacular view of the white cliff and chalk peaks separated by the deep green gorges. However, without the glaciotectonic deformation the cliffs would never have formed. Instead the Cretaceous chalk would still have been resting horizontally below the seabed, covered by glaciofluvial sand, glaciolacustrine clay and clayey till
Geological observations in the southern West Greenland basement from Ameralik to Frederikshåb Isblink in 2008
No full textIn 2008, the Geological Survey of Denmark and Greenland began a project in collaboration with the Bureau of Minerals and Petroleum of Greenland with the aim to publish a web-based, seamless digital map of the Precambrian bedrock between 61°30´ and 64°N in southern West Greenland. Such a map will be helpful for the mineral exploration industry and for basic research. Producing an updated digital map requires additional field work revisiting key localities to collect samples for geochemistry, geochronology and metamorphic petrology. The new data will help us to test and refine existing models and improve general understanding of the geological evolution of the area. Here we summarise some results from the 2008 field activities between Ame - ralik in the north and Frederikshåb Isblink in the south (Fig. 1). The area was mapped in the 1960s and 1970s, and although the 1:100 000-scale maps are of excellent quality, they do not include more recent developments in geochronology, thermobarometry and geochemistry. A notable exception is the Fiskenæsset complex (Fig. 1), which has received considerable attention after it was first mapped (Ellitsgaard-Rasmussen & Mouritzen 1954; Windley et al. 1973; Windley & Smith, 1974; Myers 1985). New tectonic models have been developed since the original 1:100 000 maps were produced, and the tectonic evolution has been com - monly ex plained in terms of terrane accretion (Friend et al. 1996)
Using spectral mixture analysis of hyperspectral remote sensing data to map lithology of the Sarfartoq carbonatite complex, southern West Greenland
No full textRemote sensing is the science of acquiring, processing, and interpreting images and related data acquired from aircraft and satellites that record the interaction between matter and electromagnetic energy (Sabins 1997). The 450–2500 nm wavelength region provides mineralogical information based on analysis of electronic absorption features in transitional metals, especially iron, and of molecular absorption features in carbonate, hydrate and hydroxide minerals (Hunt 1977). Landsat Thematic Mapper satellite images are widely used to interpret structure and geology, but due to their broad spectral bandpasses Landsat images cannot identify specific minerals. However, such details can be achieved by processing and analysing data from hyperspectral sensors. These sensors provide a unique combination of high spatial resolution and high spectral resolution imagery of the Earth’s surface unavailable from other sources (Goetz et al. 1985)
Lithostratigraphy of the Cretaceous–Paleocene Nuussuaq Group, Nuussuaq Basin, West Greenland
No full textThe Nuussuaq Basin is the only exposed Cretaceous–Paleocene sedimentary basin in West Greenland and is one of a complex of linked rift basins stretching from the Labrador Sea to northern Baffin Bay. These basins developed along West Greenland as a result of the opening of the Labrador Sea in Late Mesozoic to Early Cenozoic times. The Nuussuaq Basin is exposed in West Greenland between 69°N and 72°N on Disko, Nuussuaq, Upernivik Ø, Qeqertarsuaq, Itsaku and Svartenhuk Halvø and has also been recorded in a number of shallow and deep wells in the region. The sediments are assigned to the more than 6 km thick Nuussuaq Group (new) which underlies the Palaeogene plateau basalts of the West Greenland Basalt Group. The sediment thickness is best estimated from seismic data; in the western part of the area, seismic and magnetic data suggest that the succession is at least 6 km and possibly as much as 10 km thick. The exposed Albian–Paleocene part of the succession testifies to two main episodes of regional rifting and basin development: an Early Cretaceous and a Late Cretaceous – Early Paleocene episode prior to the start of sea-floor spreading in mid-Paleocene time. This exposed section includes fan delta, fluviodeltaic, shelfal and deep marine deposits.
The Nuussuaq Group is divided into ten formations, most of which have previously been only briefly described, with the exception of their macrofossil content. In ascending stratigraphic order, the formations are: the Kome Formation, the Slibestensfjeldet Formation (new), the Upernivik Næs Formation, the Atane Formation (including four new members – the Skansen, Ravn Kløft, Kingittoq and Qilakitsoq Members – and one new bed, the Itivnera Bed), the Itilli Formation (new, including four new members, the Anariartorfik, Umiivik, Kussinerujuk and Aaffarsuaq Members), the Kangilia Formation (including the redefined Annertuneq Conglomerate Member and the new Oyster–Ammonite Conglomerate Bed), the Quikavsak Formation (including three new members: the Tupaasat, Nuuk Qiterleq and Paatuutkløften Members), the Agatdal Formation, the Eqalulik Formation (new, including the Abraham Member), and the Atanikerluk Formation (including five members: the Naujât, Akunneq (new), Pingu (new), Umiussat and Assoq (new) Members)
Review of Survey activities 2008
No full textFollowing a number of years with major changes of the scientific environment in Denmark and also within the management of the Geological Survey of Denmark and Greenland (GEUS), 2008 was a year of stability and consolidation, a situation that will hopefully continue. Many new projects have been initiated and many previous projects have been completed at a time with strong focus on GEUS’ activities politically, commercially and from the media
Geophysical methods and data administration in Danish groundwater mapping
No full textGroundwater mapping in Denmark has high priority. It was initiated in the 1990s when the pressure on groundwater resources increased due to urban development and pollution from industrial and agricultural sources. In some areas, the groundwater mapping included survey drillings, modelling based on existing knowledge and geophysical mapping with newly developed methods that made area coverage on a large scale possible. The groundwater mapping that included development of new geophysical methods showed promising results, and led to an ambitious plan to significantly intensify the hydrogeological mapping in order to improve the protection of the Danish groundwater resources. In 1999 the Danish Government initiated the National Groundwater Mapping Programme with the objective to obtain a detailed description of the aquifers with respect to localisation, extension, distribution and interconnection as well as their vulnerability to pollution (Thomsen et al. 2004). This mapping programme covers around 40% of the area of Denmark designated as particularly valuable water abstraction areas. Water consumers finance the mapping programme by paying 0.04 € per cubic metre of consumed water. At the end of the programme in 2015, the total cost is estimated to be about 250 000 000 € with a significant part spent on geophysical mapping
Increased oil recovery from Halfdan chalk by flooding with CO2-enriched water: a laboratory experiment
No full textInjection of CO2 is a method that may increase the recovery of oil from Danish chalk reservoirs in the North Sea. The method is used elsewhere, particularly in North America, but has so far not been used in the North Sea and has nowhere been used for chalk reservoirs, and the performance of the method when used for North Sea chalk is therefore uncertain. A laboratory flooding experiment was conducted at the Geological Survey of Denmark and Greenland on a sample from the Nana-1X well of the Halfdan oil field in the Danish North Sea in order to test the efficiency of CO2-enriched water to produce additional oil from chalk. The sample is a low-permeability chalk from the Ekofisk Formation and represents rocks that are marginal to the Halfdan reservoir in an economical sense
Shallow core drilling and petroleum geology related field work in East and North-East Greenland 2008
No full textIn recent years, both the petroleum industry and governmentresearch institutions have shown renewed interest in the petroleum potential of the High Arctic. At the same time, arange of activities are taking place, aimed at defining national borders in the Arctic Ocean following ratification of article 76 of the United Nations Convention on the Law of the Sea (UNCLOS). Parallel to the general upsurge in data acquisition activities, the United States Geological Survey has carried out a Circum-Arctic Resource Appraisal (CARA), which for North-East Greenland was published in 2007. This assessment indicated that a significant petroleum exploration potential exists on the North-East Greenland shelf, in particular in the Danmarkshavn Basin and the North Danmarkshavn Salt Province (Fig. 1). The estimated potential amounts to 31 billion barrels of oil equivalents, principally in the form of natural gas. For comparison, this roughly corresponds to one third of the original reserve of the North Sea basins. The geology of the Danmarkshavn Basin and offshore areas farther to the north is only known in broad outline, since no wells have been drilled and only reconnaissance geophysical data are available. Moreover, the extensive ice cover and the overall hostile climate of the region pose significant logistical and technical challenges to data acquisition. Clearly, this emphasises the importance of analogue studies based on the much better known geology of the onshore basins in East and North-East Greenland. In 2007/2008, the Geological Survey of Denmark and Greenland (GEUS) launched a major petroleum industry-sponsored project with the objective of updating and expanding our current understanding of the petroleum geology of East and North-East Greenland. The projectis planned to continue for the next four to five years, and includes compilation of relevant existing data in the form of a geographic information system (GIS) product, supple-mented by new data obtained from shallow core drilling and new field work. Below we give a brief overview of a range of field activities that took place in East and North-East Greenland in the summer of 2008
The potential for large-scale, subsurface geological CO2 storage in Denmark
No full textCarbon capture and storage (CCS) is increasingly considered to be a tool that can significantly reduce the emission of CO2. It is viewed as a technology that can contribute to a substantial, global reduction of emitted CO2 within the timeframe that seems available for mitigating the effects of present and continued emission. In order to develop the CCS method the European Union (EU) has supported research programmes for more than a decade, which focus on capture techniques, transport and geological storage. The results of the numerous research projects on geological storage are summarised in a comprehensive best practice manual outlining guidelines for storage in saline aquifers (Chadwick et al. 2008). A detailed directive for geological storage is under implementation (European Commission 2009), and the EU has furthermore established a programme for supporting the development of more than ten large-scale demonstration plants throughout Europe. Geological investigations show that suitable storage sites are present in most European countries. In Denmark initial investigations conducted by the Geological Survey of Denmark and Greenland and private companies indicate that there is significant storage potential at several locations in the subsurface
Ladinian palynofloras in the Norwegian–Danish Basin: a regional marker reflecting a climate change
No full textThe Triassic – lower Cretaceous sedimentary succession of the Norwegian–Danish Basin has for a long time been of exploration interest, and numerous studies have been carried out. However, high-resolution correlation within the basin remains necessary, especially between the Danish and Norwegian parts of the basin. A variety of litho- and biostratigraphic schemes have been applied to the succession over the years, but lack of consistency in terminology has often led to confusing interpretations of the geological development. In this study a sequence stratigraphic scheme has been developed for the Danish Basin and a compiled palynological event stratigraphy is applied to a number of wells connecting the Danish and Norwegian parts of the basin and new marker horizons are identified. One of the aims of this study is to reach consistency in order to facilitate correlation within the basin and we also emphasise the recognition of a potentially important mid-Triassic event in the basin