GEUS Bulletin (Geological Survey of Denmark and Greenland)
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The Neoproterozoic Rivieradal Group of Kronprins Christian Land, eastern North Greenland
No full textThe Rivieradal Group, formally defined here, is confined to the Vandredalen thrust sheet of the Caledonian orogen in Kronprins Christian Land, eastern North Greenland. It comprises a succession of Neoproterozoic siliciclastic sediments that represent the fill of a half-graben basin. The syn-rift Rivieradal Group is overlain by post-rift sediments of the Hagen Fjord Group. The latter succession is present in both the thrust sheet and the Caledonian foreland to the west. In the foreland, where the Rivieradal Group is not represented, the Hagen Fjord Group disconformably overlies Palaeoproterozoic–Mesoproterozoic sandstones of the Independence Fjord Group
Prediction and risk evaluation of chalk cliff collapse: the PROTECT project
No full textA major cliff collapse took place at Store Stejlebjerg in the southern part of Møns Klint on 5 July 2003 (Fig. 1). This cliff collapse was one in a number of rock falls that has affected Møns Klint with a frequency of about one per five years. Geological investigations of the rock fall at Store Stejlebjerg were carried out by the Geological Survey of Denmark and Greenland (GEUS) after the Danish Forest and Nature Agency had asked for advice and help concerning security regulations for public access to the site. GEUS was prepared for this type of investigation due to the Survey’s engagement in the European Union project PROTECT, which aims at prediction of chalk cliff collapses. In this project a number of sites in northern Europe have been selected for detailed investigation, among which two are situated at Møns Klint, southeast Denmark (Fig. 1). This report provides a short description of the 2003 cliff collapse at Møns Klint and a brief description of the PROTECT project and its practical implications for cliff collapse evaluation
Geothermal energy in Denmark
No full textThe Geological Survey of Denmark and Greenland (GEUS) has for many years been involved with research, advisory and consultancy services concerning the assessment of the geothermal energy potential in Denmark, in close cooperation with private and public partners. The Survey’s particular responsibility has been the development of geological models to describe and predict the distribution of sandstone reservoirs suitable for geothermal exploitation. Danish geothermal resources in known sandstone aquifers are estimated to be sufficient to cover household heating requirements in Denmark for more than a century (Sørensen et al. 1998)
Immunological analysis of pesticides: a new tool in groundwater testing
No full textGroundwater is the major source of drinking water in many European countries, and in Denmark alone it accounts for more than 99% of the drinking water supply. Within the past decade pesticide residues have frequently been detected in groundwater, in many cases at levels exceeding the 0.1 µg/l limit set by the European Community. As a consequence, drinking water abstraction wells have had to be closed in many places in Denmark and other European countries, and a vast amount of money is expended to monitor groundwater pesticide levels. A degradation product of the herbicide dichlobenil, 2,6-dichlorobenzamide (BAM), is the most common cause of drinking water well closure in Denmark. Triazines and their metabolites also contaminate groundwater in many countries, and pose a similar risk to the drinking water supply. Analysis of most pesticides and their degradation products is usually carried out by concentrating the samples by solvent extraction, and identifying the contaminants using gas chromatography (GC) or high-pressure liquid chromatography (HPLC) combined with mass spectrometry (MS). These methods, although robust and well established, are very time-consuming and require specialised instrumentation. The large quantity of solvents used is another draw back to these methods, as the solvents themselves may be carcinogenic and are also well known contaminants of groundwater. The development of cheap, more sensitive and more rapid pesticide assays is therefore urgent. Due to their very high sensitivity, immunological methods have long been used in biological science for analysing a large variety of organic structures, but have only recently been introduced to environmental analysis. The benefit of such assays is primarily their high sensitivity, which allows the analysis to be undertaken without the need to concentrate the samples, but also the facility of dealing with large numbers of samples. Compared to conventional analyses, immunological methods face two major drawbacks – one related to specificity and the other to the fact that only very few chemicals can currently be analysed simultaneously. The crux of the specificity problem is that although antibodies react very specifically with particular chemical structures, these same structures may be present in analogous compounds. Thus antibodies developed to recognise, for example the herbicide atrazine might also recognise other triazines (Bruun et al. 2001). An important scientific challenge is therefore the development of highly specific assays recognising each individual compound, as well as assays recognising groups of related chemicals. With respect to the simultaneous analysis of numerous chemicals, this can be resolved by implementing the new biochip technology, which incorporates the parallellity of sample screening. On a pesticide biochip many specific immunological assays are carried out in isolated small spots on a glass or polymer surface. Each spot has a size of approximately 150 micrometers and forms a specific analysis. Such a miniaturised platform will be usable for monitoring programmes where water samples have to be screened for a range of chemical contaminants. The overall objectives of this study have been (1) to develop immunoassays for high-sensitivity analysis of specific pesticides and chemically related groups of pesticides, and (2) to transfer the developed assays to a miniaturised biochip platform in a manner allowing analysis of several pesticides simultaneously
Gold in central West Greenland – known and prospective occurrences
No full textIn 2003, the Geological Survey of Denmark and Greenland (GEUS) completed a four-year project aimed at assessing the mineral potential of the Precambrian region of West Greenland between latitudes 66° and 70°15´N. The project was part of a contract between GEUS and the Ministry of the Environment, and involved compilation of existing geoscientific data, new geological mapping, field examinations of known and potential mineral occurrences, new chemical and isotope analyses, and data interpretation. The data compilation, available on a DVD (Schjøth et al. 2004), comprises regional, systematically acquired data sets presented in a Geographic Information System environment. Aeromagnetic, aeroradiometric, stream sediment and rock geochemical and gravity data, a digital elevation model and a satellite image are included, plus descriptions of 60 mineral occurrences. Evaluation of the mineral potential is based on interpretations of the compiled information as well as on earlier investigations by the Survey, the University of Copenhagen and commercial companies (see e.g. Stendal & Schønwandt 2003; Stendal et al. 2004). From an economic point of view, the potential for gold and diamonds is the most interesting in the investigated area. This paper summarises the evaluation of the gold potential; results of diamond-related investigations are reported separately (Jensen & Secher 2004, this volume)
The fluviatile Bristol Elv Formation, a new Middle Jurassic lithostratigraphic unit from Traill Ø, North-East Greenland
No full textA new lithostratigraphic unit, the Bristol Elv Formation, is erected in this paper. It is only known from Traill Ø, East Greenland, where it unconformably overlies Triassic redbeds of the Fleming Fjord Formation and is overlain by lithologically similar shallow marine Upper Bajocian sandstones of the Pelion Formation. The age of the formation is not well constrained but is probably Early Bajocian. The Bristol Elv Formation is at least 155 m thick and consists of conglomerates, coarse-grained pebbly sandstones and subordinate mudstones, deposited in braided rivers. A finer-grained lacustrine/floodplain unit, c. 37 m thick, is interbedded with the fluvial sandstones at one locality. Deposition of the fluvio-lacustrine Bristol Elv Formation marks a major change in basin configuration and drainage patterns, reflecting the onset of the important, protracted Middle–Late Jurassic rift event in East Greenland
The Caledonian thin-skinned thrust belt of Kronprins Christian Land, eastern North Greenland
No full textKronprins Christian Land in the extreme north of the East Greenland Caledonides, exposes a thin-skinned thrust belt up to 50 km wide developed in Ordovician–Silurian platform limestones and dolostones of the Iapetus passive margin. This thrust belt is characterised by a series of SSW–NNE-trending and east-dipping Caledonian thrusts with westward displacements of generally a few kilometres each. It passes westwards into undisturbed autochthonous foreland. Based on a line and area restoration, total displacement along a well-exposed WNW–ESE section through the thrust belt amounts to 17.6 km, which represents a shortening of 45% in the line of section. Biostratigraphic control in the limestone and dolostone succession is based on conodonts and macrofossils. The alteration colours of the conodonts provide estimates of maximum burial temperatures, which show that the thickness of the overlying thrust sheets ranged from about 6 to 12.5 km from west to east across the thrust belt. Since the estimated former thickness of the Vandredalen thrust sheet above the thin-skinned parautochthonous thrust belt is insufficient to yield the temperatures attained, higher thrust sheets must once have extended across the region
Sediment distribution and transport in the shallow coastal waters along the west coast of Denmark
No full textUntil recently, studies of the regional distribution of seabed sediments off the littoral zone of the Danish North Sea coast had been concentrated on the Jutland Bank area (Fig. 1; Leth 1996, 1998). Knowledge on the sedimentary conditions and processes along the entire west coast of Jutland has, however, significantly increased as a result of 2000 km of newly acquired high-resolution seismic and side-scan sonar data, supplemented by about 100 vibrocores. These data were collected by the Geological Survey of Denmark and Greenland (GEUS) during joint projects with the Danish Coastal Authority between 1998 and 2001 (Leth et al. 1999; Larsen & Leth 2001). The coastal zone off west Jutland displays a highly dynamic environment, where sediment transport is governed by strong tidal and wave-induced currents. The net wave-generated current is south going, while the coastal current has a net direction towards the north (Knudsen et al. 2002). The direction of the net littoral drift is southward from the outlet of Limfjorden to Blåvands Huk, with net erosion north of Nymindegab and aggregation to the south; the offshore part of this depositional system has recently been studied (Larsen & Leth 2001)
Exploring for extended continental shelf claims off Greenland and the Faroe Islands – geological perspectives
No full textFollowing the expected ratification in 2004 of the United Nations Convention on the Law of the Sea (UNCLOS from 1982), Denmark, Greenland and the Faroe Islands have a period of maximum 10 years to make claims beyond 200 nautical miles (NM) in five potential areas off Greenland and the Faroe Islands (Fig. 1). In order to provide the necessary database, the Danish Continental Shelf Project has been launched by the Ministry for Science, Technology and Innovation in cooperation with the Faroese and Greenland Home Rule governments. Several institutions are participating in this project, with the Geological Survey of Denmark and Greenland (GEUS) as the coordinator of the technical work for the Greenland part of the project, and sharing the responsibility for coordination of the Faroese part with the Faroese Geological Survey (JFS)
Jurassic dinoflagellate cyst stratigraphy of Hold with Hope, North-East Greenland
No full textDinoflagellate cysts of the Middle–Upper Jurassic succession on northern Hold with Hope have been studied in order to establish a biostratigraphic framework and to date the succession. The Pelion Formation is characterised by abundant Chytroeisphaeridia hyalina and Sentusidinium spp., with some Ctenidodinium thulium and Paragonyaulacysta retiphragmata in the lower part. Mendicodinium groenlandicum appears higher in the formation followed by Trichodinium scarburghense in the upper part. The succeeding Payer Dal Formation contains Scriniodinium crystallinum, Rigaudella aemula and Leptodinium subtile in the lower part and Dingodinium jurassicum and Prolixosphaeridium granulosum in the uppermost part. The Bernbjerg Formation contains abundant Sirmiodinium grossii and Gonyaulacysta jurassica. Adnatospahaeridium sp., Cribroperidinium granuligerum, Glossodinium cf. dimorphum and Scriniodinium irregulare appear in the lower part of the formation, followed by Avellodinium spp. in the highest part. The dinoflagellate cyst assemblages in the Pelion Formation indicate an Early–Late Callovian age (C. apertum – P. athleta Chronozones). This is supported by ammonites in the lower part of the formation, which refer to the C. apertum and P. koenigi Chronozones. A significant hiatus, from Late Callovian to Middle Oxfordian, is present between the Pelion Formation and the overlying Payer Dal Formation. The age of the Payer Dal Formation is Middle Oxfordian to earliest Late Oxfordian (C. tenuiserratum – A. glosense Chronozones). The Payer Dal Formation is conformably overlain by the Bernbjerg Formation of Late Oxfordian to possibly earliest Kimmeridgian age (A. glosense – P. baylei Chronozones). The A. glosense Chronozone is also documented by abundant ammonites in the lowermost part of the formation