GEUS Bulletin (Geological Survey of Denmark and Greenland)
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Placing Greenland ice sheet ablation measurements in a multi-decadal context
No full textIn recent years, the Greenland ice sheet has been losing mass at an average rate of 262 ± 21 Gt yr–1 (2007–2011; Andersen et al. 2015). Part of this mass loss was due to increases in melt, reducing the surface mass budget (Enderlin et al. 2014). Also, the acceleration of many marine-terminating outlet glaciers increased the dynamic mass loss (Rignot et al. 2008). Both mass-loss mechanisms are linked to recent increases in atmospheric and oceanic temperatures (Dutton et al. 2015). For instance, in summer 2012 Greenland experienced exceptionally warm atmospheric conditions, causing nearly the entire ice-sheet surface to melt for two periods of several days (Nghiem et al. 2012) and contributing to the largest annual ice-sheet mass loss on record (Khan et al. 2015). This is in contrast to a return to more average conditions in 2015 (Tedesco et al. in press).
 
3D hydrogeological modelling for urban subsurface management in Odense, Denmark
No full textThe subsurface material in urban areas comprises the original geological succession together with anthropogenic modifications and deposits. The Geological Survey of Denmark previously performed geological mapping in selected Danish cities (e.g. Mertz 1974), but this practice stopped in the mid-1980s. The lack of recent systematic mapping in urban areas is apparent not only in Denmark but also in most other European countries (COST 2015). However, there is a growing demand for knowledge of the subsurface beneath our cities for a number of reasons: increased urbanisation, infiltration of excess surface water and other climate-change related measures, thermal storage, groundwater cooling and abstraction, subsurface infrastructure, infrastructure projects, etc. The physical properties of the subsurface material are in constant change due to urban growth and infrastructure development. This can strongly influence the geotechnical properties and handling of excess surface water. In order to manage both challenges and opportunities of the ground beneath the cities there is a growing need for 3D hydrogeological models that can encompass all relevant parts of the physical subsurface system and act as operational tools in its management. With the main focus on hydrogeology and the urban water cycle, the Municipality of Odense, the local waterworks (VandCenter Syd), the Geological Survey of Denmark and Greenland (GEUS) and two consultants (Alectia and I-GIS) have made a joint effort to systematically map the subsurface layers and build a 3D hydrogeological model of the subsurface of the city of Odense (Fig. 1). This paper provides an overview of the project rationale and an outline of the major results
Middle–Upper Ordovician and Silurian stratigraphy and basin development in southernmost Scandinavia
No full textA complete log-stratigraphical breakdown of the Middle Ordovician to lower Silurian shale-dominated succession is presented for the Bornholm–Skåne–Kattegat area in southernmost Scandinavia. A wireline log zonation developed for the onshore Bornholm Palaeozoic shales is extended to include the offshore Palaeozoic shales in the adjacent Rønne Graben. A complete log zonation scheme for the Cyrtograptus shale (late Llandovery–Wenlock) and the lower part of the Colonus shale (Ludlow) is presented including correlation within the Bornholm–Skåne–Kattegat area. The Cyrtograptus shale in the Bornholm area is estimated to be 400 m thick and marks the shift to a rapidly subsiding foreland basin, heralding the Caledonian Orogeny
Monitoring of pesticide leaching from cultivated fields in Denmark
No full textThe Danish Pesticide Leaching Assessment Programme (PLAP) was initiated in 1998 by the Danish Parliament in order to evaluate whether the use of approved pesticides will result in an unacceptable contamination of the groundwater, if applied under field conditions in accordance with current Danish regulation. In this programme, water samples from variably saturated soil and groundwater collected at five cultivated fields are analysed for selected pesticides and their degradation products. The PLAP results are summarised and evaluated in yearly reports and used by the Danish Environmental Protection Agency in the regulation of pesticides in Denmark (Brüsch et al. 2015). In order to represent typical farming scenarios in Denmark, the test fields are situated on meltwater and marine sands, and on tile-drained clayey soils in till areas
Middle Pleistocene interglacial deposits near Herning, Jylland, Denmark
No full textMarine interglacial deposits are fairly common and widespread in Denmark, but so far none have been reported from the Herning area in central Jylland. In 2014, the Geological Survey of Denmark and Greenland (GEUS) received samples at one metre intervals from a borehole at 55°59.3´N, 8°56.6´E (elevation 27.56 m above sea level), at Hesselvigvej 7 near Kibæk in central Jylland (Fig. 1). The succession consisted of Miocene and Quaternary deposits. The Quaternary part was dominated by glaciofluvial sand and a single till bed, but it also contained a marine clay unit (16–21 m depth, 6.5–11.5 m a.s.l.). This marine clay contained spines of the sea-urchin Echinocardium cordatum, a boreal species known from Eemian and Holocene deposits from Denmark, but unknown from interstadial deposits. A lacustrine unit between 26 and 33 m depth (5.5 m b.s.l. to 1.5 m a.s.l.) consisted of clay, calcareous-rich gyttja and diatomite. Because Quaternary marine deposits are unexpected in this part of Denmark, we report here on analyses of pollen from the lacustrine unit and foraminifera from the marine unit, and we compare these with some interglacial records from Jylland.
 
New geophysical and geological mapping of the eastern Baffin Bay region, offshore West Greenland
No full textThe Geological Survey of Denmark and Greenland has carried out a detailed mapping project in the eastern Baffin Bay region covering c. 200 000 km2 (Fig. 1). The purpose of the study was to update the previous mapping by using the most recent data and provide an improved basis for evaluation of the geological development and hydrocarbon potential of the region. After licensing rounds in 2007–2008 and 2010 considerable new geophysical and geological data were acquired in the region, and the extensive database now includes more than 100 000 km 2D seismic data and a number of wells (Fig. 1). The results of the work are summarised below and suggest deep basins and large ridges with complex structures
aFieldWork – an Android app for offline recording of geological information and data display
No full textSince 2008 the Geological Survey of Denmark and Greenland (GEUS) has used handheld devices (Personal Digital Assistents PDAs) for collecting field data in a digital format. Since PDAs are becoming obsolete and new device technology with improved functionality is available, it was decided to develop an Android-based application (app) that can be used by many mobile telephones and to test this on different devices during field work in Greenland
Cretaceous and Cenozoic dinoflagellate cysts and other palynomorphs from the western and eastern margins of the Labrador–Baffin Seaway
No full textNew palynological analysis of samples from 13 offshore wells on the Canadian Margin and six wells on the West Greenland Margin has led to a new event biostratigraphic framework for Cretaceous–Cenozoic strata of the Labrador Sea – Davis Strait – Baffin Bay (Labrador–Baffin Seaway) region. This framework is based on about 150 dinoflagellate cyst taxa and 30 acritarch, algal, fungal and plant microfossil (mostly miospore) taxa. In the systematics we include three new genera of dinocysts (Scalenodinium, Simplicidinium and Taurodinium), 16 new species of dinocysts (Chiropteridium gilbertii, Chytroeisphaeridia hadra, Cleistosphaeridium elegantulum, Cleistosphaeridium palmatum, Dapsilidinium pseudoinsertum, Deflandrea borealis, Evittosphaerula? foraminosa, Ginginodinium? flexidentatum, Hystrichosphaeridium quadratum, Hystrichostrogylon digitus, Impletosphaeridium apodastum, Scalenodinium scalenum, Surculosphaeridium convocatum, Talladinium pellis, Taurodinium granulatum and Trithyrodinium? conservatum), four emendations of dinocyst genera (Alterbidinium, Chatangiella, Chiropteridium and Surculosphaeridium), six new combinations for dinocyst species (Alterbidinium biaperturum, Deflandrea majae, Kleithriasphaeridium mantellii, Simplicidinium insolitum, Spongodinium grossum, Spongodinium obscurum), one new acritarch species (Fromea quadrangularis), one new miospore species (Baculatisporites crenulatus) and one new combination for miospores (Tiliaepollenites crassipites). Most of the taxa included provide age information, almost exclusively last occurrences (range ‘tops’), but some are useful mainly for environmental interpretations. Collectively, they provide a powerful tool for helping to establish the geological history of the Labrador–Baffin Seaway.
 
Crustal structure over the Nagssugtoqidian deformation front in West Greenland: Receiver Function analysis
No full textA marked change in crustal thickness is seen at the deformation boundary between the undisturbed Archaean core in the south and reworked Archaean gneiss in the foreland of the Nagssugtoqidian orogen in West Greenland. In addition, intra-crustal boundaries can be tentatively interpreted. This is the first information on crustal structure in the area, which is known for kimberlite, carbonatite and ultramafic lamprophyre occurrences, and diamond exploration
Burial and exhumation history of the Labrador-Newfoundland margin: first observations
No full textThe continental shelf of Labrador and Newfoundland has a long history of hydrocarbon exploration, and the accumulated oil production from the northern Grand Banks exceeds one billion barrels (Fig.1). The Canada-Newfoundland & Labrador Offshore Petroleum Board (www.cnlopb.ca) awarded several new licenses on the northern Grand Banks in 2015 and announced licensing rounds for the Labrador Sea region in the coming years