GEUS Bulletin (Geological Survey of Denmark and Greenland)
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The Continental Shelf Project of the Kingdom of Denmark – status at the beginning of 2010
No full textThe Kingdom of Denmark (Denmark, Faroe Islands and Greenland) ratified the United Nations Convention on the Law of the Sea (UNCLOS) on 16 November, 2004 and this allows for a period of ten years to submit extended continental shelf claims beyond 200 nautical miles (NM) to the Commission on the Limits of the Continental Shelf. To acquire the necessary data for delineating the extended continental shelf, the Continental Shelf Project of the Kingdom of Denmark was launched by the Ministry of Science, Technology and Innovation in cooperation with the Faroese and Greenland governments. Several institutions participate in the project. The technical work for the Greenland part is coordinated by the Geological Survey of Denmark and Greenland (GEUS) and the coordination of the Faroese part is shared between the Faroese Earth and Energy Directorate (Jarðfeingi) and GEUS. Further information can be found on the project website www.a76.dk
Amino acid analysis of pre-Holocene foraminifera from Kriegers Flak in the Baltic Sea
No full textThe Geological Survey of Denmark and Greenland (GEUS) and the Institute of Baltic Sea Research in Warnemünde (formerly the Institut für Meereskunde of the DDR) have co-operated for more than two decades on unravelling the history of the south-western part of the Baltic Sea, mainly based on shallow seismic profiling, sampling of sediment cores and analyses of core samples (Jensen et al. 2002). Here we report on some results from one of the latest joint cruises with the German research vessel Maria S. Merian
Thin-skinned thrust-fault tectonics offshore south-west Vietnam
No full textIn the c. 40 000 km2 large Phu Quoc basin south-west of Vietnam reflection seismic data suggest a thin-skinned thrust-fault complex concealed by Neogene marine sediments (Fig. 1; Fyhn et al. 2010). The deformed sedimentary succession in the complex is of Early Cretaceous age, which is documented by biostratigraphical studies of outcrops and a 500 m deep well on the Phu Quoc island. A model for the thrust-fault deformation suggests that piggy-back basins were formed during displacement along the thrust faults. The translation was 3–8 km from east to west. The model is based on detailed structural analyses of 36 seismic sections that cover the Phu Quoc basin (Fig. 1). The main structural elements in the complex are flats and ramps with hanging-wall anticlines developed above the ramps. The crests of the hanging-wall anticlines occur as remnants of partially eroded structural highs. This paper describes the thin-skinned thrust-fault structures that form the basis for the interpretation of the concealed fold-belt complex in the Phu Quoc basin
Study of a Palaeogene intrabasaltic sedimentary unit in southern East Greenland: from 3-D photogeology to micropetrography
No full textEstablishment of robust reservoir models and estimates of subsurface hydrocarbon volumes in relatively unknown subsurface settings can be improved by using data from field analogues. The discovery of the Rosebank oilfield in the Faroe–Shetland Basin showed that intrabasaltic sandstones can form important hydrocarbon reservoirs in volcanic basins (Helland-Hansen 2009). The Sødalen region in southern East Greenland (Fig. 1) forms an excellent field analogue to the Rosebank oilfield where contemporaneous Palaeogene sediments interbedded with lava units can be studied and sampled (Larsen et al. 1999). In this area many of the exposures are located along steep, inaccessible cliffs with excellent exposures that are ideal for 3-D photogeological studies based on digital high-resolution photographs taken from a helicopter
Interactive web analysis and presentation of computer-controlled scanning electron microscopy data
No full textIn the following we describe the result of the Titan Project, an interactive web application (Titan) developed at the Geological Survey of Denmark and Greenland (GEUS) together with DuPont Titanium Technologies. The main aim of Titan is to make computer-controlled scanning electron microscopy (CCSEM) data, generated at GEUS, available via the internet. In brief, CCSEM is a method automatically to detect particles with a scanning electron microscope (SEM), and based on computer-controlled imagery to measure the chemistry and grain morphology of each particle in a given sample (Knudsen et al. 2005; Bernstein et al. 2008); Keulen et al. 2008. Titan makes data available on-line so that the user can interact with the data sets and analyse them using a web browser. In addition to CCSEM data, Titan contains a global database of titanium deposits and various reports. The web application is customised, such that the functionality and amount of data available for a given user depend on the privileges of that user
The bedrock geology under the Inland Ice: the next major challenge for Greenland mapping
No full textGeological maps are of vital importance for documenting and advancing geological knowledge and they are a prerequisite for any meaningful evaluation of economic resources. In Greenland, mapping is taking place on the mainland – that for two centuries has been the traditional exploration target – and offshore, where only in the last decades has hydrocarbon exploration moved to the continental shelves. Greenland with its 2 166 000 km2 is the largest island in the world. However, the land is overwhelmed by ice. A central ice sheet – the Inland Ice – blankets some 81% of the country reducing rock outcrop to a coastal fringe 0 to 300 km wide (Fig. 1). The continental shelves comprise a little more than twice the area of this fringe, c. 830 000 km2. This preamble serves to emphasise that Greenland’s three physiographic units – exposed fringe, offshore and Inland Ice – are of very different size and that mapping has focused on the smallest acreage. Piecing together the composition of the largest, and hitherto unexplored, unit constitutes the next chapter of Greenland mapping
Earthquake in southern Sweden wakes up Denmark on 16 December 2008
No full textA moderately strong earthquake struck southern Sweden 5 km south-west of the town of Sjöbo, 60 km east of Malmö, in the early morning at 6:20 a.m. local time on 16 December 2008. The epicentre was located in Skåne, a region that is known for its extremely low seismicity, and its location was determined to be 55.5°N and 13.6°E with an uncertainty of about 6 km. A depth of 9 km with an uncertainty of 3 km was obtained from teleseismic observations at the Yellowknife seismic array, USA. Since waveform data from the Swedish national seismic network are not yet available, depth estimation using local stations has so far not been attempted. During the period 1970–2008, only three small earthquakes were detected in the region; the largest measured 2.8 on the local Richter scale. To our knowledge none of these previous earthquakes were felt by people. The historical archives dating back to 1375 show that 14 other earthquakes have been felt in the area. The largest of these, recorded in 1894, was felt over an area of 7300 km2 and had an epicentre 50 km east of the 16 December 2008 earthquake (Scandinavian Earthquake Archive 2003). The activity in southern Sweden is similar to that of northern Sjælland and north-western Jylland, and confirms the low seismicity of the region (Gregersen et al. 1991)
Soil erosion and land-use change during the last six millennia recorded in lake sediments of Gudme Sø, Fyn, Denmark
No full textThe Danish landscape is characterised by low relief and consequently the risk of soil erosion is low compared to many central and southern European countries with more variable terrain (European Environment Agency 2000; Van der Knijff et al. 2000). However, even in countries with less intensive erosion, water-induced soil erosion is recognised as an increasingly important environmental issue due to its role in the transport of nutrients, pesticides and other contaminants to rivers, lakes and coastal waters (e.g. Stone 2000)
Developing a 3-D model for the Skaergaard intrusion in East Greenland: constraints on structure, mineralisation and petrogenetic models
No full textThe Skaergaard intrusion (Fig. 1) is probably the most studied layered gabbro intrusion in the world (Wager & Deer 1939; Wager & Brown 1968; McBirney 1996; Nielsen 2004). The intrusion is c. 54.5 Ma old and was formed during the Palaeogene opening of the North Atlantic Ocean, intruding into the base of the East Greenland flood basalts. The intrusion is relatively small with a volume of c. 300 km3 (Nielsen 2004). Spectacular magmatic layering and systematic evolution in the compositions of liquidus phases and estimated melt compositions (e.g. Wager & Brown 1968) have made the intrusion the most studied example of the development of the ‘Fenner trend’ of iron enrichment in basaltic liquids (e.g. Thy et al. in press; Veksler in press)
Fingerprinting sediments along the west coast of Jylland: interpreting provenance data
No full textThe Danish North Sea coast is a dynamic sedimentary environment experiencing erosion, transport and re-deposition of sand along the coast. Because of the natural and economic value of the coastal zone expensive protection measures such as nourishment of the coast are undertaken. The present study utilises provenance analysis techniques developed at the Geological Survey of Denmark and Greenland (GEUS) to characterise the coastal sand bodies by fingerprinting the heavy minerals in the sand. The aims of the study are to test these new methods in an active sedimentary environment and to develop an understanding of transport pathways along the coast. A total of c. 40 samples have been collected and analysed as part of the project. This paper gives an outline of the project and provides examples of the methods used based on six samples from the Husby profile on the west coast of Jylland (Fig. 1). The study is a collaboration project involving GEUS and the Department of Geography and Geology (DGG) at Copenhagen University; GEUS is responsible for the analyses and DGG for sample collection