Archives - Page 4

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  Quaternary glaciation history and glaciology of Jakobshavn Isbræ and the Disko Bugt region, West Greenland: a review

  Vol. 14 (2007)

  Anker Weidick and Ole Bennike

  "Der Jakobshavner Eisstrom ist der König unter
  Den grönlandischen Gletschern. Kein anderer der
  Schnellaufenden Inlandeis-Abflüsse füllt so wie er
  Seinen Fjord mit Eisberge an."
  (Alfred Wegener 1930)

  Central West Greenland is characterised by a number of permanent ice streams, a term introduced by H.J. Rink, who conducted the first glaciological investigations in Greenland. Jakobshavn Isbræ is one of the fastest and most important ice streams draining the Greenland ice sheet. In recent years, the velocity of Jakobshavn Isbræ has increased, and since 2002 a marked recession of the ice front has taken place.

  This bulletin provides a review of the Quaternary development of the Disko Bugt region, but we also present new radiocarbon age determinations that provide constraints on the Holocene development of the Jakobshavn Isbræ. Disko Bugt was deglaciated rapidly in the early Holocene, around 10 500–10 000 years ago. The margin of the Inland Ice attained a position close to that seen today 8000–6000 years ago, and about 5000 years ago, it was located east of its present position. The subsequent Neoglacial readvance culminated around A.D. 1850, during the Little Ice Age.

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  Review of Survey activities 2006

  Vol. 13 (2007)

  Edited by Martin Sønderholm and A.K. Higgins

  The Review of Survey activities presents a selection of 17 papers reflecting the wide spectrum of activities of the Geological Survey of Denmark and Greenland, from the microscopic to the plate-tectonic level.

  Activities in Denmark: The Survey's field of activities in Denmark is illustrated by three papers on petroleum- and groundwater-related topics and one on recent environmental changes.

  Activities in Greenland: The Survey's activities in Greenland are covered by nine articles focusing on investigations related to mineral and petroleum exploration reflecting the unprecedented level of exploration activity in Greenland in 2006.

  International activities: During 2006, the Survey carried out work in more than 25 countries outside Denmark, Greenland and the Faroe Islands. This bulletin contains descriptions of three projects related to the national implementation of EU legislation, such as the Water Framework Directive, and a project in Vietnam aiming to improve the local geoscientific capacity.

   

   

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  Lithostratigraphy of the Palaeogene – Lower Neogene succession of the Danish North Sea

  Vol. 12 (2007)

  Poul Schiøler, Jan Andsbjerg, Ole R. Clausen, Gregers Dam, Karen Dybkjær, Lars Hamberg, Claus Heilmann-Clausen, Erik P. Johannessen, Lars E. Kristensen, Iain Prince and Jan A. Rasmussen

  In the mid-1990s, hydrocarbon exploration in the Danish sector of the North Sea shifted from Mesozoic targets to the lower Cenozoic, particularly in the so-called 'Siri Canyon', an erosional feature incised into the top of the Chalk on the eastern flank of the Central Graben. Intensive drilling activity in subsequent years has provided a wealth of new information concerning the nature of the Cenozoic sedimentary succession in this region and has also illustrated the need for a refined, up-dated lithostratigraphic framework.

  This bulletin presents the lithostratigraphy of the marine siliciclastic Palaeogene – Lower Neogene succession of the Danish North Sea. Existing groups (three) and formations (seven) defined elsewhere in the North Sea region are adopted and supplied with reference wells; eleven new members are defined from the Danish North Sea succession.

   

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  Precambrian crustal evolution and Cretaceous-Palaeogene faulting in West Greenland

  Vol. 11 (2006)

  Editors: A.A. Garde and F. Kalsbeek

  Central West Greenland exposes a large region of Archaean continental crust that was rifted and subsequently reworked in the Palaeoproterozoic during the Nagssugtoqidian and Rinkian orogenies. The southern margin of the Nagssugtoqidian orogen with its deformed Kangâmiut dykes is a classic example of an orogenic front, the central part of the orogen displays Palaeoproterozoic collisional structures, and the northern part illustrates strain partitioning at regional scale. The region also displays onshore expressions of the Cretaceous–Palaeogene break-up of eastern Laurentia. This bulletin contains ten research papers dealing with the Archaean and Palaeoproterozoic crustal evolution in the southern and especially northern parts of the Nagssugtoqidian orogen, a paper on the cooling history of the Rinkian fold belt farther north, and a paper presenting a detailed remote sensing and field geological analysis of onshore brittle structures in the central Nagssugtoqidian orogen, which are related to the Cretaceous–Palaeogene Ungava fault zone in the Davis Strait.

   

   

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  Review of Survey activities 2005

  Vol. 10 (2006)

  Editors: Martin Sønderholm & A.K. Higgins

  The Review of Survey activities presents a selection of 15 papers reflecting the wide spectrum of activities of the Geological Survey of Denmark and Greenland, from the microscopic to the plate tectonic level.

  Activities in Denmark: The Survey's field of activities in Denmark is illustrated by four papers on petroleum- and groundwater-related topics.

  Activities in Greenland: The Survey's activities in Greenland and the North Atlantic are covered by ten articles focusing on investigations related to mineral and petroleum exploration and climate research in the Arctic Ocean. Two papers deal with technical aspects of microanalysis by laser ablation techniques and their use in sediment provenance analysis.

  Activities in other countries: During 2005, the Survey carried out work in more than 20 countries outside Denmark, Greenland and the Faroe Islands. This volume includes an account of a project on developing an environmental sensitivity atlas for the coastal areas of Kenya.

   

   

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  Scientific results from the deepened Lopra-1 borehole, Faroe Islands

  Vol. 9 (2006)

  Editors: James A. Chalmers and Regin Waagstein

  The Faroe Islands in the northern North Altantic consist primarily of Palaeogene eruptive volcanic rocks. Two research boreholes were drilled in 1980 and 1981 on the islands, the deeper of which, Lopra-1, extended 2 km into the unexposed part of the volcanic succession.

  Exploration for hydrocarbons in the area to the south-east of the Faroe Islands and leakage of gas from the still-open Lopra-1 borehole suggested the presence of a sedimentary section below the volcanics that might contain hydrocarbons. VSP (Vertical Seismic Profiling) studies from the Lopra-1 borehole indicated the presence of seismic reflections from below its final depth that might indicate the base of the volcanic series underlain by sediments.

  These observations motivated an industry consortium to drill an extension to the Lopra-1 borehole in 1996 that, including a side-track, reached a final depth of 3565 m. The extension penetrated a thick sequence of previously unknown volcanic rocks, but not pre-volcanic siliciclastic sediments as hoped.

  This bulletin presents many new scientific studies of both the extended and original Lopra-1/1A boreholes, in some cases combined with regional studies from elsewhere in the Faroe Islands.

   

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  Structural analysis of the Rubjerg Knude Glaciotectonic Complex, Vendsyssel, northern Denmark

  Vol. 8 (2005)

  Stig A. Schack Pedersen

  The coastal cliff (99 m high at its highest point) at Rubjerg Knude on the west coast of Vendsyssel, northern Denmark. The lower two-thirds of the cliff, beneath the prominent dark sub-horizontal surface, forms part of the cross-section through the Rubjerg Knude Glaciotectonic Complex displaying imbricated thrust sheets composed of the Lønstrup Klint Formation (bluish-grey colour) and the overlying Rubjerg Knude Formation (yellow colour), both of Late Weichselian age. The thrust sheets are truncated by a glaciotectonic unconformity (the prominent surface), upon which the Kattegat Till Formation is only preserved as a boulder bed due to subsequent aeolian erosion of the till matrix. The upper third of the cliff comprises recent aeolian dune sands that have accr eted over the last 100 years and now encroach on the Rubjerg Knude lighthouse, the top of which is just visible above the clifftop. 

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  The Review of Survey activities 2004

  Vol. 7 (2005)

  Editors: Martin Sønderholm & A.K. Higgins

  The Review of Survey activities presents a selection of 18 papers reflecting the wide spectrum of activities of the Geological Survey of Denmark and Greenland, from the microbial to the plate tectonic level.

  Activities in Denmark: The Survey's activities in Denmark are documented by 11 papers. The main themes are petroleum- and groundwater-related topics and Quaternary geology but neotectonics of the Baltic Shield and new methods in provenance studies of sandstones are also touched upon.

  Activities in Greenland: The Survey's activities in Greenland and the North Atlantic are covered by six articles focusing on climate research, the mineral potential of the Precambrian basement terranes in West Greenland and on the possibility of exploiting dimension stones.

  Other countries: During 2004, the Survey carried out work in more than 20 countries outside Denmark, Greenland and the Faroe Islands. In this report a project on developing small-scale mining in Mongolia and Kyrgyzstan is described.

   

   

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  East Greenland Caledonides, stratigraphy, structure and geochronology

  Vol. 6 (2004)

  Edited by A.K. Higgins and Feiko Kalsbek

  The Caledonian orogen of East Greenland has been intensely studied over the last 30 years during a series of regional mapping expeditions. The orogen that extends between 70°N and 81°30´N in East Greenland, is now completely covered by five geological map sheets in the Survey's regional 1:500 000 series.

  This collection of six papers includes two on aspects of Neoproterozoic and Lower Palaeozoic stratigraphy. Two other papers describe structural studies, one the geometry of the thin-skinned thrust belt in Kronprins Christian Land and the second the significance of the discovery of the Eleonore Sø and Målebjerg foreland windows. The remaining two papers report the results of geochronological studies.

   

   

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  The Jurassic of North-East Greenland

  Vol. 5 (2004)

  Edited by L. Stemmerik and S. Stouge

  The Jurassic rift succession of East Greenland has been intensely studied over the last 25 years, particularly within the main outcrop areas of Jameson Land and Wollaston Forland. The more isolated and poorly known outcrops on Traill Ø, Hold with Hope, Hochstetter Forland and Store Koldewey were investigated in the late 1980s and mid-1990s in order to develop a better regional understanding of the Jurassic in eastern Greenland.

  This collection of seven papers focuses on stratigraphic and depositional aspects of the Jurassic at these localities. Comprehensive descriptions of the Jurassic on Hold with Hope and south-eastern Traill Ø are accompanied by papers covering fluvial deposits and new ammonite collections from the Middle Jurassic of Traill Ø. The bulletin is concluded by studies of the dinoflagellate cyst stratigraphy of the Middle and Upper Jurassic of Hold with Hope, Hochstetter Forland and Store Koldewey.

   

   

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  Review of Survey activities 2003

  Vol. 4 (2004)

  Editors: Martin Sønderholm & A.K. Higgins

  The Review of Survey activities presents a selection of 23 papers reflecting the wide spectrum of activities of the Geological Survey of Denmark and Greenland, from the microbial to the plate tectonic level.

  The Survey's activities in Denmark are documented by ten papers. These include discussion of the complex history of hydrocarbon filling of Danish chalk fields, the possibilities for CO2 storage in Denmark and other European countries, and the geothermal potential of Denmark. Also covered is the search for new aquifers, several aspects of groundwater vulnerability to pesticide leaching, the various cutting-edge technologies used for groundwater analysis, the environmental history of Danish lakes and the distribution and transport of sediments along the North Sea coast of Denmark. One paper deals with the management of environmental data using the Internet.

  The Survey's activities in Greenland and around the Faroe Islands are reported in ten articles. In Greenland, activities in 2003 were focused on West Greenland. Papers include a documentation of evidence for possible Jurassic source rocks off West Greenland, and reports on a mapping campaign in the Archaean province of central West Greenland that included exploration for gold and diamonds. The influence of climate change on the Greenland Inland Ice and its outlet glaciers is presented in two papers. On and around the Faroe Islands, seismic properties of basalts have been studied in detail and a geohazard study has been completed in Faroese offshore areas. The investigations relating to possible extended continental shelf claims off Greenland and the Faroe Islands that were initiated in 2003 are also outlined.

  The Survey's international activities, funded by the European Union and various national and international funds for aid to developing countries, are the subject of three papers. The PROTECT project aiming at prediction of chalk cliff collapse is reported on, as well as two developing aid projects in cooperation with the Geological Survey Department of Ghana and the Vietnam Petroleum Institute.

   

   

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  ​Late Quaternary environmental changes recorded in the Danish marine molluscan faunas

  Vol. 3 (2004)

  K. Strand Petersen

  The main result of this work was the comparison between the fossil faunas and the mollusc faunas now living before our eyes using the C.G.J. Petersen bottom community concept step by step in the seven stages from the Eemian to the Subatlantic within the seven regions in the Danish realm.

  It appears that the differences in facies made the difference between the regions and that the more temperate Eemian marine fauna was only connected with the shallow water environment.

  The climatic changes recorded in the mollusc fauna have given a clear record as far as the main trends are concerned – the interglacial/glacial cycle, however, the climatic changes during the Holocene were small.

   

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  Fish otoliths from the Paleocene of Denmark

  Vol. 2 (2003)

  Werner Schwarzhans

  The microscopic otoliths (granule of calcium carbonate in vertebrate inner ear) are becoming important for biostratigraphical evaluations in the Cenozoic of Europe. Recently, Denmark has proven to be an important area for the investigation of otoliths.

  This bulletin presents a comprehensive account on Paleocene otoliths from eastern Denmark and recorded from respectively the Fakse Quarry (Danian), Gemmas Allé (Selandian) Sundkrogen (Selandian), Kongedybet (Selandian) and Vestre Gasværk (Selandian). The Selandian locations are all in the vicinity of Copenhagen, Denmark, but today they are covered. The described otolith material from these localities is therefore obtained from older collections.

  The study describes and reinterprets the classic works of Koken (1891) and Roedel (1930) and new otolith based genera and species are introduced. The evolutionary history of the taxa is investigated and the palaeoecological significance and the palaeobiographical distribution are evaluated. The potential stratigraphical value of the taxa is investigated. Affinities to other otolith bearing locations in Europe and Greenland are discussed.

   

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  The Jurassic of Denmark and Greenland

  Vol. 1 (2003)

  Editors: Jon R. Ineson and Finn Surlyk

  The Jurassic rocks of Denmark and East Greenland record the evolution of two discrete portions of the Mesozoic rift complex, now separated by the North Atlantic Ocean. The Jurassic of Denmark and adjacent areas occurs mostly in the subsurface and research has thus focussed on the wealth of borehole and reflection seismic data resulting from over thirty years of hydrorcarbon exploration. The Jurassic of East Greenland, in contrast, is exposed in spectacular cliffs along fjords and mountainsides and has come to be regarded as a unique 'field laboratory', particularly amongst those working on the Norwegian shelf - the conjugate margin of East Greenland.

  This bulletin contains 28 articles, preceded by a short overview article, presenting the results of a period of intensive research into the Jurassic in the late 1980s and 1990s. Following detailed chronostratigraphic and biostratigraphic reviews of the Jurassic of Northwest Europe, the successions of Denmark and East Greenland are subjected to a range of stratigraphic, sedimentological, structural and geochemical studies that together provide the basis for a detailed comparison of the Jurassic evolution of the East Greenland and Danish sedimentary basins.