Review of Survey activities 2018

Geological Survey of Denmark and Greenland Bulletin | Volume 43 | 2019

Last updated: 22 July 2019

 

The Review of Survey activities for 2018 captures a snapshot of the wide range of research underway at the Geological Survey of Denmark and Greenland (GEUS).

Readers may well notice some changes to the way that this edition of the GEUS Bulletin is presented online. Each article now has its own dedicated webpage where readers will find an introductory summary for the article, along with the complete bibliographic information, a permanent DOI and a link at the top of each page to download the article as a pdf.

Another change is that there will be no printed compilation of Review of Survey activities this year. Instead, individual articles will be published online as soon as they have been accepted and are ready for publication. This means no more waiting to read a particular article of interest as this page will be regularly updated with new articles as and when they are completed. A compilation of all the articles published in this volume will be made available for download once the volume is finalised and the last article is published online.

Read more about these changes and why they are happening, here.

Explore the links below to read each of the articles in this volume of the Bulletin and bookmark this page to stay up-to-date with new articles as they are published.

ACTIVITIES IN DENMARK

Research Article | Open Access

Sea-level rise in Denmark: Bridging local reconstructions and global projections

William Colgan, Jason E. Box, Sofia Ribeiro & Kristian K. Kjeldsen

Published online: 01 July 2019

Download PDF | Article 

Between 1850 and 2006 global mean sea level rose by 24 ± 18 cm. It is projected to rise a further 52 ± 21 cm under the Representative Concentration Pathway (RCP) 4.5 scenario, which approximates the carbon emissions reductions of the ‘Paris Agreement’ climate pathway. It is projected to rise 74 ± 28 cm under the RCP8.5 scenario, which represents a ‘business-as-usual’ climate pathway (Box & Colgan 2017). These rates of recent and future sea-level rise are faster than those reconstructed for previous warm intervals, such as the Medieval Climatic Optimum (c. 1000 to 1400 CE) and the Holocene Thermal Maximum (c. 7000 to 3000 BCE) (Gehrels & Shennan 2015). Moreover, palaeo reconstructions indicate a global sea-level sensitivity of two metres per degree of warming (Levermann et al. 2013).

The forces driving global sea-level change are complex. The global sea-level budget includes the transfer of land ice into the ocean, thermal expansion of seawater, changes in land water storage, and changes in ocean basin volume (Church et al. 2013). At the local scale, the evolving planetary gravity due to shifting water and ice masses, shifting oceanic and atmospheric currents and persistent tectonic and glacial isostatic adjustment processes can also be important. Sea-level changes around the globe are therefore far from uniform (Jevrejeva et al. 2016).

Here, we highlight the value of combining palaeo reconstructions of sea level, the measured tide gauge record, and projections of future sea level. This allows us to understand local sea-level changes from the recent past in the context of global projections for the near future (0 to 2100 CE). We explore the strong differences in local sea-level histories and future projections at three Danish cities: Skagen and Esbjerg, as they have contrasting glacio-isostatic adjustment histories, and Copenhagen, where we also compare local and global drivers of present-day sea-level rise based on previously published research.

Research Article | Open Access

Climate change: Sources of uncertainty in precipitation and temperature projections for Denmark

Ernesto Pasten-Zapata, Torben O. Sonnenborg & Jens Christian Refsgaard

Published online: 24 June 2019

Download PDF | Article 

Global Climate Models (GCMs) are the main tools used to assess the impacts of climate change. Due to their coarse resolution, with cells of c. 100 km × 100 km, GCMs are dynamically downscaled using Regional Climate Models (RCMs) that better incorporate the local physical features and simulate the climate of a smaller region, e.g. a country. However, RCMs tend to have systematic biases when compared with local observations, such as deviations from day-to-day measurements, and from the mean and extreme events. As a result, confidence in the model projections decreases. One way to address this is to correct the RCM output using statistical methods that relate the simulations with the observations, producing bias-corrected (BC) projections. Here, we present the first assessment of a previously published method to bias-correct 21 RCM projections of daily temperature and precipitation for Denmark. We assess the projected changes and sources of uncertainty. The study provides an initial assessment of the bias correction procedure applied to this set of model outputs to adjust projections of annual temperature, precipitation and potential evapotranspiration (PET). This method is expected to provide a foundation for further analysis of climate change impacts in Denmark.

Research Article | Open Access

Distribution of porosity-preserving microquartz coatings in sandstones, Upper Jurassic Danish Central Graben

Margrethe T. Nielsen, Rikke Weibel, Jens Therkelsen & Henrik Friis

Published online: 22 July 2019

Download PDF | Article 

High porosity is a key factor for good reservoir sandstones for both hydrocarbon and geothermal energy exploitation. The porosity of sandstones generally decreases with increased burial depth due to compaction and cementation. However, some sandstones in the North Sea show higher porosity than expected for their burial depth, due to the presence of micro­quartz coatings (e.g. Aase et al. 1996; Hendry & Trewin 1995; Jahren & Ramm 2000; Maast et al. 2011). Siliceous sponge spicules have been documented to be an internal source of silica that promotes microquartz coatings (e.g. Hendry & Trewin 1995; Aase et al. 1996). Siliceous sponge spicules, the solid ‘skeleton’ of sponges, consist of opal-A and will dissolve when exposed to higher temperatures, thereby causing supersaturation of the formation water with respect to opal-CT and quartz, resulting in nucleation of numerous small (1–5 µm) quartz crystals (Williams et al. 1985; Hendry & Trewin 1995). To predict reservoir quality it is important to understand the distribution of porosity-preserving microquartz in clastic deposits, and yet this is still poorly understood. To address this, our study presents petrographical analyses of cored sandstone sections from wells of various depositional environments, including  back-barrier, estuarine, shoreface and gravity flows, as well as various present-day burial depths across the Danish Central Graben.

Research Article | Open Access

The channels in Storebælt, Denmark: implications of new radiocarbon ages

Ole Bennike, Niels Nørgaard-Pedersen & Jørn Bo Jensen

Published online: 24 June 2019

Download PDF | Article 

The brackish water Baltic Sea and the more saline Kattegat in the north are connected by three straits, Lillebælt, Storebælt and Øresund. Storebælt (the Great Belt) is the deepest and widest of the straits. The strait is characterised by deeply incised channels that are partly filled by sediments. The water depth in major parts of Storebælt is about 20 m, though in some areas the channels are more than 50 m deep.

The formation of the channels has been subject to discussion. Andersen (1927) suggested that the channels formed due to strong currents that are still active today or by fluvial erosion during the so-called continental period (Fastlandstiden) in the Early Holocene. At this time, the relative sea level in the region was lower than at present and a huge lake, the Ancylus Lake, which occupied the Baltic Basin, may have drained via Storebælt. Andersen dismissed the idea that the channels were formed by subglacial erosion by meltwater during the last deglaciation. More Recently, Mathiassen (1997) interpreted some of the deposits in the channels as late glacial, a viewpoint followed by Bennike et al. (2004). However, the age of the late glacial deposits in the channels are poorly constrained.

The first studies of sediment cores from Storebælt were carried out by Krog (1973), Winn (1974) and Mathiassen (1997), but these studies concentrated on the Holocene development from mires to lakes to brackish and marine environments. Wiberg-Larsen et al. (2001) documented the presence of Early Holocene river deposits. Here we report on some new ages of macrofossils from late glacial deposits in the Storebælt channels.

Research Article | Open Access

Characterising brines in deep Mesozoic sandstone reservoirs, Denmark

Hanne D. Holmslykke, Niels H. Schovsbo, Lars Kristensen, Rikke Weibel & Lars Henrik Nielsen & Tonny B. Thomsen

Published online: 17 July 2019

Download PDF| Article 

The Danish subsurface contains several sandstone units, which represent a large geothermal resource (Vosgerau et al. 2016). Currently, only three geothermal plants are operating in Denmark, but several exploration licences are expected to be awarded in 2019. Geothermal energy is exploited from deeply buried porous sandstones by bringing warm form­ation water (brine) to the surface, extracting the heat and returning the cooled water to the same sandstones. The reduced temperature of the brine during this process implies a risk of scaling, which may reduce reservoir permeability and hence injectivity. Predicting the chemical composition of formation waters, however, could help to reduce the risk associated with scaling in planned geothermal facilities.

Here, we present a regional overview of the geochem­istry of brines from deep Mesozoic sandstones in the Danish Basin and North German Basin that supplements previous studies, notably by Laier (2002, 2008). The brine composition at shallow burial typically reflects the original (connate) formation water chemistry, which is determined by the original depositional environment of the sandstone, for example fluvial or marine. However, the mineralogical composition of the sandstone changes during burial, whereby some minerals may dissolve or precipitate when exposed to higher temperatures. These mineral changes are reflected in the brine composition, which typically becomes more saline with increased burial (e.g. Laier 2008; Kharaka & Hanor 2003). 

The brine chemistry reported here shows a distinct depth trend, which reflects original connate formation waters that are modified through burial diagenesis. We have classified the brines into brine types, which are shown to be related to their depositional environment, depth, geological formation and geographical domains. 

Review Article | Open Access

Review of hydrocarbon potential in East Denmark following 30 years of exploration activities

Niels H. Schovsbo & Finn Jakobsen

Published online: 17 June 2019

Download PDF | Article 

Between 1993 and 2017, Denmark was one of the largest oil exporting countries in Europe having gained this position from its share in the highly prolific Danish Central Graben. However, outside the Central Graben few prospects have been adequately mapped, due to a lack of data in these socalled ‘white areas.’ As such, their potential for hydrocarbon accumulation remains uncertain. This paper presents an update of the prospect and play types in this area outside the Danish Central Graben, east of 6°15´E longitude (Fig. 1), based on results from the last 30 years of exploration activities. The paper is part of a resource assessment made by the Geological Survey of Denmark and Greenland (GEUS) to the Danish Energy Agency (Schovsbo & Jakobsen 2017) and is an update of a former review of the area made in 1987 (Thomsen et al. 1987). The succeeding exploration efforts have not changed the overall low expectation for the play types in the area. Here, we show that an uncertain resource is associated with both the Zechstein carbonate play in the North German Basin and the Upper Triassic – Lower Jurassic sandstone and lower Palaeozoic shale gas plays in northern Jylland. However, questions remain as to the source of hydrocarbons in the western offshore area. Specifically, we are unable to confirm (or refute) whether these structures are sourced via long-distance migration of hydrocarbons from the Danish Central Graben.

ACTIVITIES IN GREENLAND

Research Article | Open Access

Greenland ice sheet mass balance assessed by PROMICE (1995–2015)

William Colgan, Kenneth D. Mankoff, Kristian K. Kjeldsen, Anders A. Bjørk, Jason E. Box, Sebastian B. Simonsen, Louise S. Sørensen, S. Abbas Khan, Anne M. Solgaard, Rene Forsberg, Henriette Skourup, Lars Stenseng, Steen S. Kristensen, Sine M. Hvidegaard, Michele Citterio, Nanna Karlsson, Xavier Fettweis, Andreas P. Ahlstrøm, Signe B. Andersen, Dirk van As & Robert S. Fausto

Published online: 08 July 2019

Download PDF| Article 

The Programme for Monitoring of the Greenland Ice Sheet (PROMICE) has measured ice-sheet elevation and thickness via repeat airborne surveys circumscribing the ice sheet at an average elevation of 1708 ± 5 m (Sørensen et al. 2018). We refer to this 5415 km survey as the ‘PROMICE perimeter’. Here, we assess ice-sheet mass balance following the input- output approach of Andersen et al. (2015). We estimate ice-sheet output, or the ice discharge across the ice-sheet grounding line, by applying downstream corrections to the ice flux across the PROMICE perimeter. We subtract this ice discharge from ice-sheet input, or the area-integrated, ice sheet surface mass balance, estimated by a regional climate model. While Andersen et al. (2015) assessed ice-sheet mass balance in 2007 and 2011, this updated input-output assessment now estimates the annual sea-level rise contribution from eighteen sub-sectors of the Greenland ice sheet over the 1995–2015 period.

Research Article | Open Access

Update of annual calving front lines for 47 marine terminating outlet glaciers in Greenland (1999–2018)

Jonas K. Andersen, Robert S. Fausto, Karina Hansen, Jason E. Box, Signe B. Andersen, Andreas P. Ahlstrøm, Dirk van As, Michele Citterio, William Colgan, Nanna B. Karlsson, Kristian K. Kjeldsen, Niels J. Korsgaard, Signe H. Larsen, Kenneth D. Mankoff, Allan Ø. Pedersen, Christopher L. Shields, Anne Solgaard & Baptiste Vandecrux

Published online: 26 June 2019

Download PDF| Article 

The Programme for Monitoring of the Greenland Ice Sheet (PROMICE) is dedicated to monitoring changes in the mass budget of the Greenland ice sheet, including monitoring of the calving front lines of marine terminating outlet glaciers. Here, we present an updated collection of annual measurements of end-of-melt-season calving front lines for 47 marine terminating outlet glaciers in Greenland between 1999 and 2018. We also present an example application of the data set, in which we estimate area changes for this group of glaciers since 1999. The Greenland calving front lines were measured from optical satellite imagery obtained from Landsat, Aster, and Sentinel-2 (Table 1). The PROMICE calving front product is freely available for download as ESRI shapefiles.

Research Article | Open Access

U-Pb dating identifies titanite precipitation in Paleogene sandstones from a volcanic terrane, East Greenland

Rikke Weibel & Tonny B. Thomsen

Published online: 08 July 2019

Download PDF| Article 

Titanite (CaTiSiO5) occurs as a rare mineral in magmatic and metamorphic rocks. It is commonly found in clastic sedimentary rocks as an accessory heavy mineral – a mineral of high density. Recently, U-Pb dating of single-grains of detrital titanite has been shown to be a useful tool in sedimentary provenance studies (e.g. McAteer et al. 2010; Thomsen et al. 2015). Titanite U-Pb geochronologies can add important information to constrain the sediment sources of rocks and basins, and can help date precipitation of titanite. However, there are a number of complicating factors that must be taken into consideration for reliable application of titanite U-Pb dating in provenance studies.

First, titanite is less stable than zircon – the most commonly employed dating target. For example, in Palaeocene sediments in the North Sea, titanite rarely occurs as detrital grains at burial depths greater than 1400 m (Morton 1984). It can also show dissolution features due to weathering and burial diagenesis (e.g. Morton 1984; Turner & Morton 2007). Second, titanite may precipitate during burial diagenesis, which would reflect the burial history of sediments and not their provenance. Precipitation of authigenic titanite is documented from deeply buried (i.e. at temperatures greater than 100°C) volcaniclastic sandstones and mudstones (Helmond & Van de Kamp 1984; Milliken 1992) and intrusion-associated mineralisation in volcanic Permian sandstones (van Panhuys-Sigler & Trewin 1990). Moreover, titanite also occurs in shallow-buried Jurassic sandstones with no volcanic affinity (Morad 1988). Thus, the formation of titanite is not necessarily linked to a volcaniclastic source, but nevertheless, the presence of volcanic material seems to promote titanite precipitation. If authigenic titanite precipitation was incorrectly identified as detrital, this would have considerable implications for provenance investigations, as apparently titanite-rich source rocks would be wrongly inferred to be present in the sediment source area. Here, we present examples from the Kangerlussuaq Basin in southern East Greenland of what appeared to be detrital titanite. However, new U-Pb dating reveals that the titanite formed authigenically, and hence contributed to the burial history, and not the provenance, of the sediments.

Review Article | Open Access

Liverpool Land Basement High, Greenland: visualising inputs for fractured crystalline basement reservoir models

Graham Banks, Stefan Bernstein, Sara Salehi, Pierpaolo Guarnieri, Dennis Bird, Catherine Hamblett, David Peacock & Jon Foster

Published online: 22 July 2019

Download PDF| Article 

Basement highs are large structural features, commonly buried in sedimentary basins (Busby & Azor 2012). They are of interest for natural resources exploration and research because of their ability to influence migration and entrapment of petroleum (Trice 2014) and water, and the deposition of metals (Hitzman 2005; Borg et al. 2012). Three-dimensional (3D) reservoir models (e.g. Shepherd 2009) are built to evaluate and model fluid-filled basement reservoirs (Ringrose & Bentley 2015). However, subsurface data are expensive, difficult to obtain and are often widely spaced. Ideally, basement reservoir models would be constrained by rock, fracture and mineral vein data from appropriate outcrop analogues (acknowledging that subaerial basement rocks have, by definition, a different uplift history than subsurface basement). The Liverpool Land Basement High (LLBH) in Greenland is an uplifted and well-exposed basement high located between two sedimentary basins, and thus provides a valuable analogue for fractured basement-hosted mineral, oil and geothermal reservoirs. 

The Geological Survey of Denmark and Greenland (GEUS) conducted reconnaissance work on the LLBH in 2018 to assess the quality of the exposure of basement palaeo-weathering profiles and fault-fracture networks. Here, we introduce the LLBH, the concept of fractured basement reservoir modelling, and how studying the LLBH can help enhance reservoir modelling of fractured basement. We present some of our preliminary observations of LLBH fault-fracture networks and discuss how the exposed sediment-basement features and processes might aid industry and research in their top basement mapping activities. We propose that LLBH provides a particularly suitable analogue for industry and research to analyse: (a) multiscale fracture system connectivity, (b) fluid migration and fluid-rock reaction processes, (c) input parameters for basement reservoir modelling and (d) top basement geomorphologies and processes.

Research Article | Open Access

Comparison of ASTER and Sentinel-2 spaceborne datasets for geological mapping: a case study from North-East Greenland

Sara Salehi, Christian Mielke, Christian Brogaard Pedersen & Simun Dalsenni Olsen

Published online: 17 July 2019

Download PDF| Article 

Spaceborne remote sensing is a suitable tool for early mineral exploration and surveying large areas of high Arctic environment in a fast and cost-effective manner. While spaceborne data have been used widely to map geology in arid areas, similar approaches for remotely-sensed geological mapping of Arctic environments is yet to be developed. Freely available spaceborne optical data provides detailed information of high-quality that could potentially reduce resource exploration risk in remote regions. To this end, this study compares the use of two different multispectral spaceborne datasets (i.e. the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Sentinel-2) to map geological units in and around Wollaston Forland, North-East Greenland – an area rich in Jurassic and Cretaceous sedimentary rocks and important targets for offshore petroleum exploration. Multispectral image sensors simultaneously capture image data within multiple wavelength ranges (bands) across the electromagnetic spectrum. Each band is commonly described by the band number and the band wavelength centre position. Here, we identify the bands most suitable for geological mapping in an Arctic setting, using the Wollaston Forland area as an example. We compare the results obtained by processing spaceborne data with a published geological map for the area (Henriksen 2003).

Research Article | Open Access

Mapping glacial rock flour deposits in Tasersuaq, southern West Greenland

Ole Bennike, Jørn Bo Jensen, Frederik Næsby Sukstorf & Minik T. Rosing

Published online: 17 July 2019

Download PDF| Article 

Poor soil quality in the tropics is largely due to the rapid weathering of minerals and leaching of dissolved nutrients in the warm and humid climate. If weathered minerals are not replaced by new minerals, for example due to volcanic activity, then soil fertility continues to decline over time. Therefore, it is necessary to use increasing amounts of fertilisers to feed growing populations in the tropics. Most nutrients come from geological deposits; the only exception is nitrogen, which can be extracted from the atmosphere. Nutrients that are mined constitute a limited resource. Hence the known occurrences of phosphorous can only cover the current demand for a few decades (van Vuuren et al. 2010).

In recent years, investigations have been conducted to see if the productivity of nutrient-poor soils can be improved by the application of glacial rock flour from Greenland. Rock flour in southern West Greenland consists of fine-grained silt, formed by the grinding of bedrock by stones and boulders embedded in the basal part of glaciers. Preliminary results indicate that plants cultivated in soils with rock flour can achieve increased growth (M.T. Rosing, unpublished data 2019). However, the research is still in its early days and many questions remain. We do not know why adding rock flour to soil results in increased growth. Maybe the silt fraction improves the soil properties. Also we do not know if it is feasible to mine rock flour and transport it to the tropics. As a first step towards answering some of these questions, our aim here was to simply map and sample the glacial rock flour in Tasersuaq, a large proglacial lake in southern West Greenland, c. 105 km north-east of Nuuk.

Research Article | Open Access

Preliminary landslide mapping in Greenland

Kristian Svennevig

Published online: 17 June 2019

Download PDF| Article 

The landslide of 17 June 2017 in Karrat Fjord, central West Greenland, highlighted the need for a better understanding of landslides and landslide-generated tsunamis in Greenland and motivated a landslide screening project in 2018, led by the Geological Survey of Denmark and Greenland (GEUS; see also Svennevig et al. this volume). A central part of this project was to conduct a preliminary mapping of Quaternary and historical landslides in Greenland – the first effort of its kind. The main objective was to establish a landslide inventory database that can be used to identify areas prone to landslides and serve as a tool for gaining a better understanding of where, when and why catastrophic landslides take place in Greenland.

This paper describes the workflow used to produce the preliminary landslide inventory of Greenland and discusses some of the initial results. To date (June 2019), I have mapped 564 landslides with the vast majority situated in the Nuussuaq Basin between Sigguup Nunaa (Svartenhuk Halvø), and Qeqertarsuaq (Disko) in West Greenland (Fig. 1). The inventory mapping is mainly based on observations and analyses of remotely sensed imagery and pre-existing geological maps. The mapping coverage was not systematic for all of Greenland, but focused on postglacial, potentially tsunamigenic landslides in inhabited coastal regions, i.e. on relatively large landslides on coastal slopes, mainly in West Greenland and small areas of East Greenland. However, smaller and inland landslides were included when they were encountered. Similarly, the less inhabited parts of Greenland were provisionally screened, but call for more thorough, systematic mapping in the future.

Research Article | Open Access

A multidisciplinary approach to landslide monitoring in the Arctic: Case study of the March 2018 ML 1.9 seismic event near the Karrat 2017 landslide

Kristian Svennevig, Anne Munck Solgaard, Sara Salehi, Trine Dahl-Jensen, John Peter Merryman Boncori, Tine B. Larsen & Peter H. Voss

Published online: 01 July 2019

Download PDF| Article 

The landslide of 17 June 2017 at Karrat Fjord, central West Greenland, triggered a tsunami that caused four fatalities. The catastrophe highlighted the need for a better understanding of landslides in Greenland and initiated a recent nation-wide landslide screening project led by the Geological Survey of Denmark and Greenland (GEUS; see also Svennevig (2019) this volume).

This paper describes an approach for compiling freely available data to improve GEUS’ capability to monitor active landslides in remote areas of the Arctic in near real time. Data include seismological records, space borne Synthetic Aperture Radar (SAR) data and multispectral optical satellite imagery. The workflow was developed in 2018 as part of a collaboration between GEUS and scientists from the Technical University of Denmark (DTU). This methodology provides a model through which GEUS will be able to monitor active landslides and provide relevant knowledge to the public and authorities in the event of future landslides that pose a risk to human life and infrastructure in Greenland.

We use a minor event on 26 March 2018, near the site of the Karrat 2017 landslide, as a case study to demonstrate 1) the value of multidisciplinary approaches and 2) that the area around the landslide has continued to be periodically active since the main landslide in 2017.

OTHER SURVEY ACTIVITIES

Research Article | Open Access

The North Atlantic Provenance Database: an introduction

Christian Knudsen, Martin Sønderholm, Tjerk Heijboer, Jeppe Å. Kristensen & Dag Bering

Published online: 22 July 2019

Download PDF| Article 

The amount of provenance information available for onshore and offshore sedimentary deposits in the North Atlantic Region is substantial and rapidly increasing. These data provide an improved understanding of reservoir geology (quality, diagenetic issues, regional source-to-sink relations and local stratigraphic correlations), and thereby can reduce hydrocarbon exploration risk. As such, the number of proprietary, industry-related and public research provenance studies has increased considerably in recent years, and the development and use of new analytical techniques has also caused a surge in the number of grains, isotopes and chemical elements analysed in each study. As a result, it is today close to impossible for the individual researcher or petroleum geologist to draw on all existing provenance data. And the vast expansion of data availability demands new and better methods to analyse and visualise large amounts of data in a systematic way

To this end, the Geological Survey of Denmark and Greenland (GEUS) and the Norwegian Petroleum Directorate (NPD) have established a web-based database of provenance data for the North Atlantic area: the North Atlantic Provenance Database. Construction of the database was funded jointly by GEUS and NPD. Future maintenance and further development will be funded by the petroleum industry by subscription to the database. Here, we provide a brief introduction to the database and its future development and expansion. We highlight the current capabilities with an example from East Greenland.

BULLETIN 43, REVIEW OF SURVEY ACTIVITIES 2018

Download Volume 43 (coming soon)

ISSN (online): 1904-4666

Volume DOI: https://doi.org/10.34194/GEUSB-201943- 

First articles published online: 17 June 2019

Final article published online: TBA

Edited by: Catherine Jex

Layout and graphic production: Jacob Lind Bendtsen

Illustrations: Jacob Lind Bendtsen

Editorial Secretary: Jane Holst

Published: Geological Survey of Denmark and Greenland (GEUS), Copenhagen | Danish Ministry of Energy, Utilities, and Climate | GEOCENTER Denmark.