Archives

• The PGE-Au Mineralisation of the Skaergaard intrusion: precious metal minerals, petrography and ore genesis

  Vol. 54 (2023)

  Guest Editor: Rune B.E. Larsen, NTNU, Norway

  The Skaergaard PGE-Au Mineralisation, alias the Platinova Reef, is hosted in a series of mineralisation levels within a suite of bowl-shaped macrorhythmic layers in the upper Middle Zone of the Skaergaard intrusion. The intrusion is exposed 68°N in East Greenland. The occurrence defines its own type due to its exceptional structure and mineralogy. A wealth of mineralogical data is available in laboratory reports for individual samples and in peer-reviewed publications, but none of these account for the lateral and stratigraphic variations in the compositions of the minerals and phases of PGE and Au parageneses in the gabbros of the intrusion. In this special issue, the authors, Nikolay S. Rudashevsky, Troels F.D. Nielsen and Vladimir N. Rudashevsky, collate and describe the mineralogical data for the first-formed PGE-rich and last-formed gold-rich mineralisation levels and integrate these with petrogenetic models. A foreword is provided by the Guest Editor of this special issue, Rune B.E. Larsen.

• Annual Volume 2023

  Vol. 53 (2023)

  An annual collection of articles submitted to GEUS Bulletin and published throughout 2023. This issue is open until the end of 2023.

• Marine geodiversity and geosystem services in Scandinavian seas

  Vol. 52 (2022)

  Guest editors: Kaskela Anu (Geological Survey of Finland), Margaret Dolan (Geological Survey of Norway) and Verner Brandbyge Ernstsen (Geological Survey of Denmark and Greenland).

  This special issue highlights the application and development of the concepts of geodiversity and geosystem services in a marine context with a specific focus on the Scandinavian regional seas.

  The articles published in this issue address the role of marine geodiversity and geosystem services in relation to blue growth, green transition and sustainability and the importance and value of including abiotic components of nature in relation to nature conservation, protection and geoheritage. Hence, this issue promotes key elements for maritime or marine spatial planning and management in the marine realm in a changing climate.

  The editors intend for this issue to contribute to the UN Decade of Ocean Science for Sustainable Development by contributing to the scientific knowledge base.

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  Descriptive text to the Geological map of Denmark, 1:50 000, Møn 1511 I, 1511 IV and 1512 II

  Vol. 51 (2022)

  This is an English translation of Vol. 48 (2021), which was originally published in Danish.

  Translated and edited by: Adam A. Garde

  Written by: Stig A. Schack Pedersen, Peter Gravesen

  The Møn map area covers the islands of Møn, Nyord, Degneholm, Lindholm and Langø. It also includes the south-east corner of Sjælland, Kalvehave and the north-east corner of Falster, Grønsund.

  The map sheet description provides the systematic, geological description of the soil types that appear on the geological map. The geology is described to a depth of 60–80 m a.s.l., by four geological cross-sections based on boreholes from the Jupiter database at GEUS.

  The near-surface geology on Møn is dominated by clayey till, which covers c. 70% of the land area. Sandy deposits cover c. 20% of the land area and consist of glaciofluvial sand and marine sand. The latter forms the Ulvshale peninsula with an extended crescentic spit and the marine sandflat east of Nyord. In the valleys, postglacial peat is interbedded with freshwater sand and clay, which is particularly characteristic of infill in the former fjord at Borre Sømose.

  The Cretaceous chalk at Møns Klint is the most significant geological formation in the area. Here, a series of steep sheets of Cretaceous chalk form parallel hill ridges. The highest point is Aborre Bjerg (143 m a.s.l.). Sheets of Cretaceous chalk are also found elsewhere, including Hvideklint on the south coast of Møn.

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  Lithostratigraphy, geology and geochemistry of the Tertiary volcanic rocks on Svartenhuk Halvø and adjoining areas, West Greenland

  Vol. 50 (2022)

  The upper Cretaceous–Tertiary Nuussuaq Basin in West Greenland contains a thick succession of siliciclastic sediments and overlying volcanic rocks. The first studies in the early 19th century were centred on the coal and fossils in the sediments and minerals in the volcanic rocks. The present focus of interest includes modern stratigraphic and volcanological studies to decipher the basin evolution and support hydrocarbon and mineral exploration.

  This special issue of GEUS Bulletin presents the lithostratigraphy, geology and geochemistry of the Paleocene and Lower Eocene volcanic rocks on the Svartenhuk Halvø and adjoining areas to the north and east. The olivine-rich Vaigat Formation is more than 2000 m thick and comprises three members, of which the lowest is crustally contaminated. The basaltic Svartenhuk Formation is up to 1350 m thick and comprises four members. It extends from Svartenhuk Halvø to large areas to the north and east. The basaltic Naqerloq Formation, of early Eocene age, occurs in western Svartenhuk Halvø in erosional remnants up to 300 m thick. The comprehensive descriptions and chemical analyses are intended to serve as a guide for future studies.

  This bulletin is a companion to bulletin vol. 39 and vol. 40 on the volcanic rocks of the Vaigat and Maligât Formations on Disko and Nuussuaq.

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  Annual Volume 2022

  Vol. 49 (2022)

  An annual collection of articles submitted to GEUS Bulletin, published throughout 2022.

  Cover photo by @Robbie Shone / Greenland Caves Project, as featured in Smith & Moseley (2022; DOI:10.34194/geusb.v49.8298).

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  Kortbladsbeskrivelse, Geologisk kort over Danmark, 1:50 000, Møn Dele af 1511 I, 1511 IV og 1512 II

  Vol. 48 (2021)

  Den geologiske kortbladsbeskrivelse af Møn omfatter foruden hovedøen Møn tillige øerne Nyord, Degneholm, Lindholm og Langø. Desuden er det sydøstligste hjørne af Sjælland, Kalvehave, og det nordøstligste hjørne af Falster, Grønsund, medtaget på kortbladet.

  Kortbladsbeskrivelsen giver den systematiske, geologiske beskrivelse af jordarterne, som forekommer på det geologiske kort. Desuden indgår beskrivelsen af geologien ned til en dybde af 60–80 m u.h.o., som er repræsenteret ved fire geologiske tværsnit baseret på boringerne i GEUS’ boreprøve-database Jupiter.

  De overfladenære geologiske forhold på Møn domineres af moræneler, som dækker ca. 70% af landområdet. Sandede aflejringer, som dækker ca. 20%, består henholdsvis af smeltevandssand og marint sand. Sidstnævnte danner halvøen Ulvshale med et udbygget krumodde-system og den marine sandflade øst for Nyord. I dalstrøgene findes Postglacialt tørv mellemlejret af ferskvandssand og -ler, hvilket især er karakteristisk for opfyldningen af den tidligere fjordarm ved Borre Sømose.

  Den mest markante geologiske dannelse på Møn er skrivekridtet på Møns Klint. Her danner en serie stejlt stående flager af skrivekridt parallelle bakkerygge i landskabet, hvor det højeste punkt er Aborre Bjerg 143 m o.h. Flager af skrivekridt findes ikke kun ved Møns Klint, men indgår mange steder i landskabets opbygning, som f.eks. langs Hvideklint på sydkysten af Møn.

  This volume is available in English: Vol. 51 (2022).

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  Annual Volume 2021

  Vol. 47 (2021)
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  Jurassic stratigraphy of East Greenland

  Vol. 46 (2021)

   

  The Jurassic basin of East Greenland has an international reputation not only for its well-exposed examples of rift-related depositional systems but also as a source of direct analogues for the subsurface of the Norwegian shelf and the North Sea. In addition, the basin has played an important role over many years in research into Boreal Jurassic biostratigraphy and ammonite taxonomy. A well-constrained stratigraphic framework is an essential component of basin analysis, and understanding of the stratigraphy of the Jurassic in East Greenland has advanced in the last decades in parallel with intensive sedimentological, sequence stratigraphic and palaeontological research. 

  The aim of this bulletin, therefore, is to present a comprehensive, well-illustrated revision and up-date of the Jurassic stratigraphy of East Greenland to guide and constrain research efforts in future years. The Jameson Land Supergroup spans from the uppermost Triassic to the lowermost Cretaceous and comprises five groups that together include a total of 25 formations and 48 members. Many of these units are revised in this bulletin, and three new formations and 14 new members are introduced.

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  Denudation history and landscape development in East Greenland: Part Two

  Vol. 45 No. 2 (2021)

   

  The geology of East Greenland north of 70°N – including the Wandel Sea Basin – exposes unique evidence of the basin development between the Devonian collapse of the Caledonian Orogen and the extrusion of volcanics during Palaeogene break-up of the North-East Atlantic. Do the unconformities in the stratigraphic record represent periods of stability and nondeposition? Or do the unconformities represent periods of subsidence and accumulation of rocks followed by episodes of uplift and erosion which removed those rocks? How do the flat-topped mountains fit into the tectonic framework of the region? And when did these elevated plateaus reach their present elevation? To answer such questions, we have used apatite fission-track analysis (AFTA) and vitrinite reflectance (VR) data together with stratigraphic landscape analysis and observations from the stratigraphic record to study the denudation history and landscape development of East Greenland.

  In three separate, but interrelated papers, we present the results of these investigations. We show that episodes of kilometre-scale vertical movements (both ups and downs) have affected East Greenland and areas beyond, before as well as after the opening of the North-East Atlantic. Part two consists of a single monograph. Two shorter papers are published in part one.

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  Denudation history and landscape development in East Greenland: Part One

  Vol. 45 No. 1 (2021)

   

  The geology of East Greenland north of 70°N – including the Wandel Sea Basin – exposes unique evidence of the basin development between the Devonian collapse of the Caledonian Orogen and the extrusion of volcanics during Palaeogene break-up of the North-East Atlantic. Do the unconformities in the stratigraphic record represent periods of stability and nondeposition? Or do the unconformities represent periods of subsidence and accumulation of rocks followed by episodes of uplift and erosion which removed those rocks? How do the flat-topped mountains fit into the tectonic framework of the region? And when did these elevated plateaus reach their present elevation? To answer such questions, we have used apatite fission-track analysis (AFTA) and vitrinite reflectance (VR) data together with stratigraphic landscape analysis and observations from the stratigraphic record to study the denudation history and landscape development of East Greenland.

  In three separate, but interrelated papers, we present the results of these investigations. We show that episodes of kilometre-scale vertical movements (both ups and downs) have affected East Greenland and areas beyond, before as well as after the opening of the North-East Atlantic. Part one consists of two papers. A third, longer paper is published in part two.

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  Vol. 44 (2020)
• 

  Review of Survey activities 2018

  Vol. 43 (2019)
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  Petroleum geology of the Upper Jurassic – Lower Cretaceous of East and North-East Greenland: Blokelv-1 borehole, Jameson Land Basin

  Vol. 42 (2018)

  Editors: Jon R. Ineson and Jørgen A. Bojesen-Koefoed

  The exposed Jurassic succession in East and North-East Greenland has long been presented as an analogue for equivalent deeply buried strata on the Norwegian conjugate shelf and offshore North-East Greenland. In particular, the Upper Jurassic marine mudstone succession is often ascribed source-rock potential as proven from coeval rocks on the Northwest European margin. Previous outcrop investigations have not convincingly confirmed this potential, however, and three boreholes were drilled between 2008 and 2010 to provide full coverage of the Upper Jurassic – Lower Cretaceous petroleum source-rock succession in eastern Greenland. The Blokelv-1 borehole was drilled in 2008 in central Jameson Land to investigate the Middle Oxfordian – Lower Volgian Hareelv Formation, representing the lowermost part of the composite source-rock succession.

  The common aim of the collection of eight scientific papers in this bulletin, introduced by an account of the technical and logistic challenges of the drilling operation, is to document the significance of the Hareelv Formation in a petroleum geological context. Papers on the biostratigraphy, sedimentology, provenance and diagenesis establish the framework and geological history of the succession while companion papers on the source-rock potential, burial and exhumation history and igneous intrusive activity in the region contribute to an improved understanding of the petroleum geology of the Jameson Land Basin.

   

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  Review of Survey activities 2017

  Vol. 41 (2018)

  Editors Adam A. Garde, Ole Bennike and W. Stuart Watt

  The 22 contributions in this issue of Review of Survey activities demonstrate the broad field of activities performed by the Geological Survey of Denmark and Greenland and external partners.

  Seven papers on Danish geology comprise an investigation of reservoir sandstones for oil and gas production in the Danish Central Graben, an evaluation of alternative depository sites for unwanted brine in a commercial gas storage facility, and a study of alum shale nanoporosity, which provides new insight into the Danish shale gas play. Till deposits are addressed in a paper on chalk-glacitectonite and in an example of using ground-penetrating radar for a structural study. Two offshore articles describe Neogene oil-bearing diatom ooze in the North Sea and a large area of unusual, inclined bedding in Skagerrak.

  In Greenland, four papers deal with remote sensing in geological mapping, describing advanced methodology and results of photogrammetry and hyperspectral mapping from mobile platforms such as helicopters and boats, and a fifth paper discusses the need for systematic updates of Survey maps as new data are acquired. A new geophysical map offshore West Greenland is also presented and geochemical data from sedimentary rocks in North Greenland are used to discuss potential mineralisation processes related to the world-scale zinc deposit at Citronen Fjord. The ongoing monitoring of the Greenland ice sheet is addressed in four contributions, including the newly established radioactive waste study at Camp Century and a reconstruction of past sea-ice extent off eastern Greenland back to the 19th century. Besides, records of European whaling and trading in the 17th–19th centuries are used to discuss past climate variations in West Greenland.

  The issue also contains an evaluation of future use of and demand for rare-earth elements in wind turbines, a study of laser ablation techniques in the analysis of fish otoliths for fish stock monitoring, and an account of current activities to maintain and expand a common geological database for the European Union.