Geological Survey of Denmark and Greenland Bulletin最新文献

{"title":"Chalk-glacitectonite, an important lithology in former glaciated terrains covering chalk and limestone bedrock","authors":"S. Pedersen, P. Gravesen, K. Hinsby","doi":"10.34194/geusb.v41.4333","DOIUrl":"https://doi.org/10.34194/geusb.v41.4333","url":null,"abstract":"A glacitectonite is defined as a brecciated sediment or a cataclastic sedimentary rock formed by glaciotectonic deformation (Pedersen 1988). The term tectonite was initially introduced by Sander (1912), mainly for tectonically brecciated metamorphic rocks in the Alps. In the classic work on cataclastic rocks, Higgins (1971) stated that the term covered all rocks with fabric displaying coordinated geometric features related to continuous flow during deformation.Therefore brecciated lithologies formed by glaciotectonic deformations can be termed tectonites. Banham (1977) suggested the prefix glaci- to clarify the relation to glacial dynamics. Furthermore, Pedersen (1988) suggested the application of the bedrock prefix. Thus, a chalk-glacitectonite is a brecciated chalk formed by shear deformation during a glacial advance over an exposed bedrock surface of chalk (Fig. 1). Hence the term describes a sedimentary rock in which the primary structures are so disturbed that they cannot be continuously traced, and a glacitectonic fabric developed as joint fractures or shear surfaces superimposed on the lithology. The significance of recognising chalk-glacitectonite from chalk and limestone bedrock is the difference in textural properties, which is fundamental in geological modelling. In areas dominated by glaciotectonic complexes, which include thrust sheets of pre-glacial sedimentary rocks, the sheets are subject to shearing and dragged along the sole of the ice during its movement over the glaciotectonic complex. Due to truncation and shear-drag, the glacitectonite forms at the base of the deformational layer in a lodgement till. From the source area, which typically is a detachment anticline, the glacitectonite thins out in the direction of transport from 1–2 m (Fig. 2) to a thin shear zone only a few centimetres thick over a distance of one to a few kilometres (Pedersen 1996). Moreover, brecciation of thrust sheets displaced by glacial thrusting occurs within glaciotectonic complexes. The deformation ranges from initially anastomosing jointing (Figs 1, 3) to brecciation with bedrock clasts in crushed bedrock matrix (Fig. 4). The tectonic breccia distributed from the décollement zone at the base to the truncating glacial unconformity at the top may additionally be termed glacitectonites. Here we describe the occurrence and identification of chalk-tectonites.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73178239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Remote geological mapping using 3D photogrammetry: an example from Karrat, West Greenland","authors":"E. V. Sørensen, P. Guarnieri","doi":"10.34194/geusb.v41.4343","DOIUrl":"https://doi.org/10.34194/geusb.v41.4343","url":null,"abstract":"The geology of the Paleoproterozoic Karrat Group in West Greenland (71°–74°50´N) was investigated during the field seasons 2015–2017, using a combination of digital photogrammetry and traditional field work in a collaboration between the Geological Survey of Denmark and Greenland and the Ministry of Minerals Resources of Greenland. The area is characterised by steep alpine terrain with more than 2000 m of relief that in many places is completely inaccessible, which makes field work extremely difficult. Therefore 3D mapping using digital photogrammetry is an invaluable tool in the investigation of the region. Early geological investigations of the area involved the first use of photogrammetry in Greenland (Henderson & Pulvertaft 1987). This contribution serves as an example of the present-day use of photogrammetry in geological interpretation, following the workflow outlined in Sørensen & Dueholm (2018). During the last three years, more than 50 000 stereo images have been collected using handheld, calibrated digital cameras while conducting field work in the area (Rosa et al. 2016, 2017, 2018). The images, which cover large parts of the steep cliff sections in which the geology is superbly exposed, are essential to the ongoing revision of the geological map sheets covering the area. Here we present a small subset of the data from the island of Karrat (Fig. 1), showcasing the potential of 3D geological mapping in Greenland as well as presenting new insights into the geology of the Karrat Group.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91155188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mineral mapping by hyperspectral remote sensing in West Greenland using airborne, ship-based and terrestrial platforms","authors":"S. Salehi, Simon Mose Thaarup","doi":"10.34194/geusb.v41.4339","DOIUrl":"https://doi.org/10.34194/geusb.v41.4339","url":null,"abstract":"While multispectral images have been in regular use since the 1970s, the widespread use of hyperspectral images is a relatively recent trend. This technology comprises remote measurement of specific chemical and physical properties of surface materials through imaging spectroscopy. Regional geological mapping and mineral exploration are among the main applications that may benefit from hyperspectral technology. Minerals and rocks exhibit diagnostic spectral features throughout the electromagnetic spectrum that allow their chemical composition and relative abundance to be mapped. Most studies using hyperspectral data for geological applications have concerned areas with arid to semi-arid climates, and using airborne data collection. Other studies have investigated terrestrial outcrop sensing and integration with laser scanning 3D models in ranges of up to a few hundred metres, whereas less attention has been paid to ground-based imaging of more distant targets such as mountain ridges, cliffs or the walls of large pits. Here we investigate the potential of using such data in well-exposed Arctic regions with steep topography as part of regional geological mapping field campaigns, and to test how airborne hyperspectral data can be combined with similar data collected on the ground or from moving platforms such as a small ship. The region between the fjords Ikertoq and Kangerlussuaq (Søndre Strømfjord) in West Greenland was selected for a field study in the summer of 2016. This region is located in the southern part of the Palaeoproterozoic Nagssugtoqidian orogen and consists of high-grade metamorphic ortho- and paragneisses and metabasic rocks (see below). A regional airborne hyperspectral data set (i.e. HyMAP) was acquired here in 2002 (Tukiainen & Thorning 2005), comprising 54 flight lines covering an area of c. 7500 km2; 19 of these flight lines were selected for the present study (Fig. 1). The target areas visited in the field were selected on the basis of preliminary interpretations of HyMap scenes and geology (Korstgård 1979). Two different sensors were utilised to acquire the new hyperspectral data, predominantly a Specim AisaFenix hyperspectral scanner due to its wide spectral range covering the visible to near infrared and shortwave infrared parts of the electromagnetic spectrum. A Rikola Hyperspectral Imager constituted a secondary imaging system. It is much smaller and lighter than the Fenix scanner, but is spectrally limited to the visible near infrared range. The results obtained from combining the airborne hyperspectral data and the Rikola instrument are presented in Salehi (2018), this volume. In addition, representative samples of the main rock types were collected for subsequent laboratory analysis. A parallel study was integrated with geological and 3D photogrammetric mapping in Karrat region farther north in West Greenland (Rosa et al. 2017; Fig. 1).","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"168 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85562774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Examining the rare-earth elements (REE) supply– demand balance for future global wind power scenarios","authors":"P. Kalvig, Erika Machacek","doi":"10.34194/geusb.v41.4350","DOIUrl":"https://doi.org/10.34194/geusb.v41.4350","url":null,"abstract":"Rare-earth elements (REE) are considered Critical Raw Materials (CRM; EC 2018; US Department of the Interior 2018) and essential in the technological transformation of the energy sector into carbon-free technologies such as wind turbines, electrified transport and LED-lights. The new technologies have led to swiftly expanding markets for REE products, in which China has achieved a monopolistic role in all segments of the REE value chains. Political strategies aimed to establish REE supplies outside China are currently being implemented within the EU and in other Western countries in order to ensure an adequate future REE supply. However, new REE value chains outside China have not yet materialised. The aim of this paper is to assess whether the global REE supply from present and potential mines can keep pace with the REE demand for the expanding offshore wind energy sector (Fig. 1). A successful development of this sector outside China relies on an adequate supply of particularly neodymium (Nd) and to some extent praseodymium (Pr), terbium (Tb) and dysprosium (Dy), used in permanent magnets for windmill generators. In 2015, about 82% of the global Nd-oxide production was used in the permanent magnets production (Adamas 2016). Here we evaluate the future supply and demand situations for Nd, Pr, Tb and Dy in the global wind energy sector in the form of three scenarios, one for 2020 and two for 2030 based on high and low demand. The balance is discussed. Our assessment reflects the challenge caused by limited insight into the REE supply chains inside China, and the figures presented in this paper are therefore only indicative.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"496 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80022160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Circum-Greenland, ice-thickness measurements collected during PROMICE airborne surveys in 2007, 2011 and 2015","authors":"L. Sørensen, S. Simonsen, R. Forsberg, L. Stenseng, H. Skourup, S. Kristensen, W. Colgan","doi":"10.34194/GEUSB.V41.4348","DOIUrl":"https://doi.org/10.34194/GEUSB.V41.4348","url":null,"abstract":"The Greenland ice sheet has experienced an average mass loss of 142 ± 49 Gt/yr from 1992 to 2011 (Shepherd et al. 2012), making it a significant contributor to sea-level rise. Part of the ice- sheet mass loss is the result of increased dynamic response of outlet glaciers (Rignot et al. 2011). The ice discharge from outlet glaciers can be quantified by coincident measurements of ice velocity and ice thickness (Thomas et al. 2000; van den Broeke et al. 2016). As part of the Programme for monitoring of the Greenland Ice Sheet (PROMICE; Ahlstrøm et al. 2008), three airborne surveys were carried out in 2007, 2011 and 2015, with the aim of measuring the changes in Greenland ice-sheet thicknesses. The purpose of the airborne surveys was to collect data to assess the dynamic mass loss of the Greenland ice sheet (Andersen et al. 2015). Here, we present these datasets of observations from ice-penetrating radar and airborne laser scanning, which, in combination, make us able to determine the ice thickness precisely. Surface-elevation changes between surveys are also presented, although we do not provide an in-depth scientific interpretation of these.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78308112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analytical procedures for 3D mapping at the Photogeological Laboratory of the Geological Survey of Denmark and Greenland","authors":"E. V. Sørensen, Mads Dueholm","doi":"10.34194/geusb.v41.4353","DOIUrl":"https://doi.org/10.34194/geusb.v41.4353","url":null,"abstract":"Photogrammetry is a classical remote sensing technique dating back to the 19th century that allows geologists to make three-dimensional observations in two-dimensional images using human stereopsis. Pioneering work in the 1980s and 1990s (Dueholm 1992) combined the use of vertical (nadirlooking) aerial photographs with oblique stereo images from handheld small-frame cameras into so-called multi-model photogrammetry. This was a huge technological step forward that made it possible to map, in three dimensions, steep terrain that would otherwise be inaccessible or poorly resolved in conventional nadir-looking imagery. The development was fundamental to the mapping and investigation of e.g. the Nuussuaq basin (Pedersen et al. 2006). Digital photogrammetry, the all-digital version of multi-model photogrammetry, is nowadays an efficient and powerful geological tool that is used by the Photogeological Laboratory at the Geological Survey of Denmark and Greenland (GEUS) to address geological problems in a range of projects from 3D mapping to image-based surface reconstruction and orthophoto production. Here we present an updated description (complementary to Dueholm 1992) of the analytical procedures in the typical digital workflow used in current 3Dmapping projects at GEUS.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81866772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards a common geological data infrastructure for Europe","authors":"J. Tulstrup, M. Pedersen","doi":"10.34194/geusb.v41.4352","DOIUrl":"https://doi.org/10.34194/geusb.v41.4352","url":null,"abstract":"Geology does not respect national borders. Hence, in order to get geological overviews of Europe, input from geological surveys in more than 35 countries is required. European policy makers have several times been forced to rely on the US Geological Survey to provide e.g. resource estimates from the European continent, but for obvious reasons there is a wish to base European decision making on European knowledge. Consequently, the European Commission and the European Parliament have formulated a request for the establishment of a ‘Geological Service for Europe’. In its strategy towards 2020, EuroGeoSurveys (EGS) addresses the creation of such a service through three pillars. EGS is an umbrella organisation through which national geological survey organisations of 36 European countries cooperate, referred to below as national surveys. The three pillars are designed to integrate input from all national surveys into a system that can swiftly act on urgent needs for knowledge-based decision support. The three pillars relate to joint research, data integration and sharing of facilities (Fig. 1). Whilst the third pillar has only recently been dealt with, the two first have already advanced through a number of recent initiatives. Having been a key player in numerous EU projects for many years, the Geological Survey of Denmark and Greenland (GEUS) has attained a central role in the implementation of these two pillars of the strategy, both as coordinator of the European Geological Data Infrastructure (EGDI, www.europe-geology.eu) and as one of the biggest players in the so-called GeoERA programme. GEUS participates in ten projects and is a partner in the secretariat and the coordinator of the GeoERA Information Platform. The present paper outlines the main steps towards the current situation and provides a background for GEUS’ role in this.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"55 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81403910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New subsurface mapping offshore southern West Greenland using geophysical and geological data","authors":"U. Gregersen, M. Andersen, H. Nøhr-Hansen, E. Sheldon, T. Kokfelt, M. Olivarius, C. Knudsen, K. G. Jakobsen, J. Adolfssen","doi":"10.34194/geusb.v41.4342","DOIUrl":"https://doi.org/10.34194/geusb.v41.4342","url":null,"abstract":"The West Greenland continental margin has been the subject of petroleum exploration by companies and research projects since the 1970s and many data have been acquired since. Licensing rounds issued by the Greenland authorities in 2002 and 2004 offshore southern West Greenland resulted in company licenses which led to data acquisition and three exploration wells. The extensive new data form a basis for updated mapping by means of data, new analyses of the subsurface geology and improved understanding of the stratigraphy and the geological development. The Geological Survey of Denmark and Greenland (GEUS) has recently completed a comprehensive mapping project of the subsurface in an area covering 116 000 km2 offshore southern West Greenland (Fig. 1). The results include maps displaying large structural highs and faults, Cretaceous sedimentary basins and volcanic areas, illustrated by cross-sections through the area. A new seismic stratigraphy with eight mega-units from the seabed to the basement was also defined. In addition, studies from wells of biostratigraphy and petrology were carried out that provide important new information. The new data include extensive 2D seismic data and eight wells including the three exploration wells AT2-1, AT7-1 and LF7-1 drilled in 2011 by Cairn Energy (Fig. 1). Key results of the work are summarised below.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84616951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"European trading, whaling and climate history of West Greenland documented by historical records, drones and marine sediments","authors":"N. Mikkelsen, A. Kuijpers, S. Ribeiro, M. Myrup, I. Seiding, A. Lennert","doi":"10.34194/geusb.v41.4344","DOIUrl":"https://doi.org/10.34194/geusb.v41.4344","url":null,"abstract":"The European trading and whaling activities of the 17th– 19th centuries provide records of climate and sea- ice conditions off West Greenland in the form of ships’ logs and other official documents in many archives around Europe. These documents, combined with evidence from marine sediments, help describe climate changes in general, and seaice volume changes in particular, in connection with human activity in the region. The Greenland National Museum & Archives in Nuuk (NKA) hosts a unique collection of original documents presenting detailed insight into weather and ice conditions as well as the daily life of the colonial centres and outposts recorded by the documents of the Danish administration. These documents also reveal many aspects of the interaction between the Inuit and Europeans from 1779 onwards. Information retrieved from the archives in Nuuk has been combined with results from palaeo-environmental investigations of marine sediment cores to unravel climate variability and changes in sea ice. This information has been supplemented with data from an extensive field programme using drones to document onshore remains from the whaling period in the Disko Bugt region (Fig. 1).","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"94 1","pages":"67-70"},"PeriodicalIF":0.0,"publicationDate":"2018-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79450164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Update of the seamless 1:500 000 scale geological map of Greenland based on recent field work in the Wandel Sea Basin, eastern North Greenland","authors":"K. Svennevig","doi":"10.34194/geusb.v41.4337","DOIUrl":"https://doi.org/10.34194/geusb.v41.4337","url":null,"abstract":"Geological maps are core products of national geological surveys and represent the sum of geological knowledge of any given area. However, dedicated and extensive mapping projects in the Arctic are mostly a thing of the past due to difficulty in financing such costly basic research efforts. Today, an overview of the geology of Greenland is portrayed by a seamless digital 1:500 000 scale geological map (Kokfelt et al. 2013; Pedersen et al. 2013), based on printed maps on this scale produced since 1982 by the Geological Survey of Denmark and Greenland (GEUS; see Holst et al. 2013). The digital map now makes it possible to update smaller areas with new, published or otherwise quality-controlled geological data (e.g. Kolb et al. 2016). This ensures that the map reflects the current state of geological knowledge without undertaking extensive new mapping to update individual map sheets, as has previously been the modus operandi. An online version of the map is available from www.greenmin.dk/map. However, procedures are required to ensure that updates are carried out routinely and that the quality and coherence of the updated map is of the Survey’s standards. Results of recent field work in the Wandel Sea Basin (Fig. 1) and in particular the publication of a new geological map sheet Kilen on a scale of 1:100 000 (Svennevig in press) have implications for the geology shown on the above mentioned 1:500 000 scale seamless geological map of Greenland. The post-Devonian part of this map in eastern North Greenland has been updated according to the results of studies published since the publication of the original printed maps (Bengaard & Henriksen 1986; Jepsen 2000). The changes do not call for an update of the 1:2 500 000 scale geological map of Greenland (Henriksen et al. 2009).","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81338905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}