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Peel, J.S. 2020. Middle Cambrian trilobites (Miaolingian, Ehmaniella Biozone) from the Telt Bugt Formation of Daugaard-Jensen Land, western North Greenland.
Nyborg, E., Surlyk, F. & Thibault, N. 2020. Provenance of Medieval atlantes in the Ribe Cathedral, Denmark, based on geological and palaeontological investigations.
Schultz, B.P., Vickers, M.L., Huggett, J., Madsen, H., Heilmann-Clausen, C., Friis, H. & Suess, E. 2020. Palaeogene glendonites from Denmark
Bjerager, M., Alsen, P., Bojesen-Koefoed, J., Fyhn, M.B.W., Hovikoski, J., Ineson, J., Nøhr-Hansen, H., Nielsen, L.H., Piasecki, S. & Vosgerau, H. 2020. Cretaceous lithostratigraphy of North-East Greenland
Clemmensen, L.B., Kent, D.V., Mau, M., Mateus, O. & Milàn, J. 2020. Triassic lithostratigraphy of the Jameson Land basin (central East Greenland), with emphasis on the new Fleming Fjord Group.
Pasquinelli, L., Felder, M., Gulbrandsen, M.L., Hansen, T.M., Jeon, J.-S., Molenaar, N., Mosegaard, K. & Fabricius, I.L. 2020. The feasibility of high-temperature aq- uifer thermal energy storage in Denmark: the Gassum Formation in the Stenlille structure.
Piasecki, S., Bojesen-Koefoed, J.A. & Alsen, P. 2020. Geology of the Lower Cretaceous in the Falkebjerg area, Wollaston Forland, northern East Greenland.
Winsløw, L.B., Pedersen, S.A.S., Boldreel, L.O. & Nørmark, E. 2020. Wrench-fault structures superimposed by glaciotectonic complexes, interpreted from high- resolution reflection-seismic sections and boreholes along the western bank of Esrum Sø, north-east Sjælland, Denmark.
Schovsbo, N.H., Ponsaing, L., Mathiesen, A., Bojesen-Koefoed, J.A., Kristensen, L., Dybkjær, K., Johannessen, P., Jakobsen, F. & Britze, P. 2020. Regional hydrocarbon potential and thermal reconstruction of the Lower Jurassic to lowermost Cretaceous source rocks in the Danish Central Graben.
Bennike, O., Pantmann, P. & Aarsleff, E. 2020. Lateglacial and Holocene floras and faunas from the Salpetermosen area, north-east Sjælland, Denmark.
Milàn, J., Falkingham, P.L. & Mueller-Töwe, I. J. 2020. Small ornithopod dinosaur tracks and crocodilian remains from the Middle Jurassic Bagå Formation, Born-holm, Denmark: Important additions to the rare Middle Jurassic vertebrate faunas of Northern Europe
Middle Cambrian trilobites (Miaolingian, Ehmaniella Biozone) from the Telt Bugt Formation of Daugaard-Jensen Land, western North Greenland
Peel, J.S. 2020. Middle Cambrian trilobites (Miaolingian, Ehmaniella Biozone) from the Telt Bugt Formation of Daugaard-Jensen Land, western North Greenland. Bulletin of the Geological Society of Denmark, vol. 68, pp. 1–14. ISSN 2245-7070.
https://doi.org/10.37570/bgsd-2020-68-01
Abstract
A small fauna of middle Cambrian trilobites is described from the upper Telt Bugt Formation of Daugaard-Jensen Land, western North Greenland, and the formation is formally defined. Blainiopsis holtedahli and Blainiopsis benthami, originally described from the equivalent Cape Wood Formation of Bache Peninsula, Nunavut, Canada, are documented in an assemblage assigned to the Ehmaniella Biozone (Topazan Stage of North American usage), Miaolingian Series, Wuliuan Stage, of the international standard. Two new species are proposed: Ehmaniella sermersuaqensis and Clappaspis tupeq.
Keywords: Laurentia, North Greenland, Cambrian, Miaolingian (Wuliuan), trilobites.
Addresses:John S. Peel, Department of Earth Sciences (Palaeobiology), Uppsala University, Villavägen 16, SE-75236 Uppsala, Sweden.
Provenance of Medieval atlantes in the Ribe Cathedral, Denmark, based on geological and palaeontological investigations
Nyborg, E., Surlyk, F. & Thibault, N. 2020. Provenance of Medieval atlantes in the Ribe Cathedral, Denmark, based on geological and palaeontological investigations.
Bulletin of the Geological Society of Denmark, vol. 68, pp. 15–21. ISSN 2245-7070.
https://doi.org/10.37570/bgsd-2020-68-02
Abstract
An atlante is a corbel figure (or pillar support) sculpted in the form of a man carrying a heavy load. A group of well-preserved stone carved atlantes from c. 1250 carrying the vaults of the Ribe Cathedral in western Jylland, Denmark, represents the antique titan Atlas and are up to 150 cm high. Their obviously foreign origin has so far remained uncertain. The figures are made of a relatively soft, sandy limestone. A new nannofossil analysis of small chips of the chalky and sandy limestone narrows the age of the stone down to the late Campanian (Late Cretaceous). Upper Campanian sandy limestones of this type are exposed in the Münster Basin in North Rhine-Westphalia, western Germany. The Campanian Baumberger Sandstein in this region fits well with the atlantes in terms of lithology and age and is the only possible provenance of the stone. Around 1250 the Baumberger Sandstein was used for baptismal fonts as far north as Ostfriesland at the Dutch-German border, and it is a novel finding of this investigation that it even reached Denmark. The stone was most likely floated along the rivers Lippe and Rhine and shipped via the Wadden Sea to Ribe. It is a remarkably long transport distance for historic commercial stone transportation in continental northern European art in the High Middle Ages.
Keywords: Ribe Cathedral, Medieval sculpture, provenance, late Campanian, coccoliths, Baumberger Sandstein, Münster Basin.
Addresses:Ebbe Nyborg, National Museum of Denmark, Frederiksholms Kanal 12, DK-1220 Copenhagen K, Denmark. Finn Surlyk and Nicolas Thibault, Department of Geoscience and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
Corresponding author: Finn Surlyk
Palaeogene glendonites from Denmark
Schultz, B.P., Vickers, M.L., Huggett, J., Madsen, H., Heilmann-Clausen, C., Friis, H. & Suess, E. 2020. Palaeogene glendonites from Denmark.
Bulletin of the Geological Society of Denmark, Vol. 68, pp. 23–35. ISSN 2245-7070.
https://doi.org/10.37570/bgsd-2020-68-03-rev
File replaced 2022–03–29: Erroneous author name is now correct.
Original publication: https://doi.org/10.37570/bgsd-2020-68-03
Abstract
Pristinely preserved mineral pseudomorphs called glendonites, up to 1.6 m long, from the Palaeogene strata of Denmark allow detailed crystallographic characterisation and add to the understanding of the transformation of the precursor mineral, ikaite (CaCO3·6H2O), to calcite, which constitutes the glendonite. We describe Danish pseudomorphs after ikaite from two localities and formations: the Early Eocene Fur Formation and the Late Oligocene Brejning Formation. This detailed study highlights that key aspects such as morphology and mode of occurrence of these ancient glendonites are identical to those of their parent mineral ikaite, when it grows in marine sediments. Systematic distortion of the angles in glendonite and marine sedimentary ikaite relative to the ideal ikaite symmetry may arise due to the incorporation of organic matter into the crystal structure, and we demonstrate the similarity between modern and ancient ikaite formation zones in the marine sedimentary realm with respect to organic matter.
Keywords: Glendonite, ikaite, morphology, distorted symmetry, Fur Formation, Brejning Formation
Addresses: Bo Pagh Schultz, Museum Salling, Fur Museum, Nederby 28, DK-7884 Fur, Denmark. Madeleine L. Vickers, Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. Jennifer Huggett, Department of mineralogy, Natural History Museum, Cromwell Road, London SW7 5BD, UK. Henrik Madsen, Fossil og Molermuseet, Museum Mors, Skarrehagevej 9, DK-7900 Mors, Denmark. Claus Heilmann-Clausen and Henrik Friis, Institut for Geoscience, Aarhus Universitet, Høegh-Guldbergs Gade 2, DK-8000 Aarhus C, Denmark. Erwin Suess, GEOMAR Helmholtz Centre for Ocean Research, D-24148 Kiel, Germany; also College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97330, USA.
Cretaceous lithostratigraphy of North-East Greenland
Bjerager, M., Alsen, P., Bojesen-Koefoed, J., Fyhn, M.B.W., Hovikoski, J., Ineson, J., Nøhr-Hansen, H., Nielsen, L.H., Piasecki, S. & Vosgerau, H. 2020. Cretaceous
lithostratigraphy of North-East Greenland.
Bulletin of the Geological Society of Denmark, vol. 68, pp. 37–93. ISSN 2245-7070.
https://doi.org/10.37570/bgsd-2020-68-04
Abstract
An updated and revised lithostratigraphic scheme is presented for the Cretaceous of North-East Greenland from Traill Ø in the south to Store Koldewey in the north. The Ryazanian to lower Maastrichtian succession is up to several kilometres thick and comprises four groups, 12 formations and 18 members. The groups record the tectonic evolution of the East Greenland depocentre on the western flank of the evolving proto-Atlantic seaway. The Wollaston Forland Group encompasses the uppermost Jurassic – lowermost Cretaceous rift-climax succession and contains the Lindemans Bugt and Palnatokes Bjerg Formations; two new members of the latter formation are erected from Store Koldewey. Post-rift Cretaceous strata are referred to the new Brorson Halvø Group and the Home Forland Group. The Brorson Halvø Group (uppermost Hauterivian – middle Albian) is dominated by slope and basinal mudstones of the new Stratumbjerg Formation but also includes fluvio-deltaic and shallow marine sandstones of the revised Steensby Bjerg Formation on northern Hold with Hope and submarine slope apron breccias and conglomerates of the revised Rold Bjerge Formation on Traill Ø. The Home Forland Group covers the middle Albian – Coniacian succession. The basal unconformity records an important mid-Albian tectonic event involving intrabasinal uplift, tilting and erosion, as exemplified by the middle Albian conglomerates of the new Kontaktravine Formation on Clavering Ø. The Home Forland Group is dominated regionally by mud-dominated slope to basinal deposits of the elevated and revised Fosdalen Formation; it also includes lowstand basin-floor fan sandstones of the new upper Albian Langsiden Member. The new Jackson Ø Group (upper Turonian – lower Maastrichtian), records a phase of basin reorganisation marked by a significant fall in sedimentation rate in North-East Greenland, probably linked to rift events in, and bypass to, the central proto-Atlantic rift system. The base of the group is an erosional unconformity on Traill Ø and Geographical Society Ø overlain by submarine slope-apron conglomerates of the Turonian Månedal Formation. The base is conformable on Hold with Hope but is defined by a condensed interval (the Coniacian Nanok Member) that is succeeded conformably by slope and basin-floor turbidite sandstones of the Coniacian–Santonian Østersletten Formation and slope to basinal mudstones of the Campanian – lower Maastrichtian Knudshoved Formation. The new Leitch Bjerg Formation of Campanian slope-apron conglomerates and sandstones in eastern Geographical Society Ø erosionally overlies the Knudshoved Formation.
Keywords: Cretaceous, lithostratigraphy, North-East Greenland
Addresses: Morten Bjerager, Peter Alsen, Jørgen Bojesen-Koefoed, Michael B.W. Fyhn, Jussi Hovikoski, Jon Ineson, Henrik Nøhr-Hansen, Lars H. Nielsen, Henrik Vosgerau, all Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. Stefan Piasecki, GLOBE Institute, University of Copenhagen, Øster Voldgade 5–7, DK-1350 Copenhagen K, Denmark; also Geological Survey of Denmark and Greenland (GEUS).
Triassic lithostratigraphy of the Jameson Land Basin (central East Greenland), with emphasis on the new Fleming Fjord Group
Clemmensen, L.B., Kent, D.V., Mau, M., Mateus, O. & Milàn, J. 2020. Triassic lithostratigraphy of the Jameson Land basin (central East Greenland), with emphasis on the new Fleming Fjord Group.
Bulletin of the Geological Society of Denmark, vol. 68, pp. 95–132. ISSN 2245-7070.
https://doi.org/10.37570/bgsd-2020-68-05-rev
File replaced 2021–05–08: Erroneous rotation directions in the original publication are now correct.
Original publication: https://doi.org/10.37570/bgsd-2020-68-05
Abstract
The lithostratigraphy of the Triassic deposits of the Jameson Land Basin in central East Greenland is revised. The new Scoresby Land Supergroup is now composed of the Wordie Creek, Pingo Dal, Gipsdalen and Fleming Fjord Groups. This paper only deals with the lithostratigraphy of the late Early-Late Triassic continental deposits of the latter three groups with emphasis on the vertebratebearing Fleming Fjord Group. The new Pingo Dal Group consists of three new formations, the Rødstaken, Paradigmabjerg and Klitdal Formations (all elevated from members), the new Gipsdalen Group consists of three new formations, the Kolledalen, Solfaldsdal (with the new Gråklint Member) and Kap Seaforth Formations (all elevated from members), and the new Fleming Fjord Group is subdivided into three new formations, the Edderfugledal, Malmros Klint and Ørsted Dal Formations (all elevated from members). The Edderfugledal Formation contains two cyclic bedded, lacustrine members, a lowermost Sporfjeld Member (elevated from beds), and an uppermost Pingel Dal Member (elevated from beds). The lacustrine red beds of the Malmros Klint Formation are not subdivided. The lacustrine and fluvial Ørsted Dal Formation contains three new members. In the eastern and central part of the basin, the formation is initiated by cyclic bedded, red lacustrine mudstones of the Carlsberg Fjord Member (elevated from beds), while in the northwestern part of the basin the lowermost part of the formation is composed of grey fluvial conglomerates and sandstones with subordinate red mudstones of the Bjergkronerne Member (elevated from beds). The uppermost part of the formations in most of the basin is composed of cyclic bedded, variegated lacustrine mudstones and grey to yellowish marlstones of the Tait Bjerg Member (elevated from beds). The sediments in the Fleming Fjord Group contain remains of a rich and diverse vertebrate fauna including dinosaurs, amphibians, turtles, aeotosaurs, pterosaurs, phytosaurs and mammaliaforms. Most vertebrate bones have been found in uppermost Malmros Klint Formation, and in the Carlsberg Fjord and Tait Bjerg Members. The Norian–early Rhaetian, lacustrine Fleming Fjord Group was deposited at about 41° N on the northern part of the supercontinent Pangaea. Lacustrine sedimentation was controlled by seasonal as well as longer-term (orbital) variation in precipitation. Precipitation was probably brought to the basin by southwesterly winds. The lacustrine sediments of the uppermost Fleming Fjord Group show deposition during increasingly humid conditions changing the lake environment from an ephemeral lake-steppe area to a perennial lake. This evolution of lake environment suggests a change from a winter-wet temperate climate to one with precipitation throughout the year.
Keywords: Triassic, East Greenland, lithostratigraphy, lacustrine sediments, palaeoclimate, vertebrate fossils
Addresses: Lars B. Clemmensen, Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. Dennis V. Kent, Lamont – Doherty Earth Observatory, Palisades, NY 10968, USA and Earth and Planetary Sciences, Rutgers University, Picataway, NJ 08854, USA. Malte Mau, Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. Octávio Mateus, GEOBIOTEC, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa and Museu da Lourinhã, Portugal. Jesper Milàn, Geomuseum Faxe Østsjællands Museum, Østervej 2b, 4640 Faxe, Denmark.
The feasibility of high-temperature aquifer thermal energy storage in Denmark: the Gassum Formation in the Stenlille structure
Pasquinelli, L., Felder, M., Gulbrandsen, M.L., Hansen, T.M., Jeon, J.-S., Molenaar, N., Mosegaard, K. & Fabricius, I.L. 2020. The feasibility of high-temperature aquifer thermal energy storage in Denmark: the Gassum Formation in the Stenlille structure.
Bulletin of the Geological Society of Denmark, Vol. 68, pp. 133–154, ISSN 2245-7070.
https://doi.org/10.37570/bgsd-2020-68-06_rev
File replaced 2022–02–24: Erroneous stratigraphic levels in figures 8, 9, 10 and 11 of the original publication are now correct
Original publication: https://doi.org/10.37570/bgsd-2020-68-06
Abstract
Heat storage in the Danish subsurface is gaining increasing interest for optimizing the use of energy resources, but no deep heat storage facilities have yet been established. As an analogue we study the Gassum Formation in the Stenlille structure that is presently used for gas storage. This allows us to discuss geological and technical characteristics of an aquifer relevant for heat storage in Denmark. We develop a 3D model for a high-temperature aquifer thermal energy storage system using analysis of geological core data, sedimentological description, geophysical data including well logs and seismic lines, as well as a finite difference model to calculate the recovery efficiency, heat storage capacity and thermal breakthrough time. Based on geostatistical methods we made three realisations and found similar results for the three cases. In accordance with results from published simplified models we found a high recovery efficiency of 70% after 4 years and 69% after 20 years, a high heat storage capacity of 1.8×1018 J, and a long thermal breakthrough time of 66–77 years. These results reflect the excellent reservoir properties of the Gassum Formation in Stenlille, characterised by a uniformly layered sand/shale sedimentology, a high average porosity of 25% and a high permeability of 1000 to 10 000 mD of sandstone intervals.
Keywords: HT-ATES, sedimentary rocks, rock properties modelling, geostatistics, recovery efficiency, storage capacity, thermal breakthrough time.
Addresses:
Lisa Pasquinelli and Ida Lykke Fabricius, Department of Civil Engineering, DTU BYG, Nordvej Building 119, DK-2800 Kgs. Lyngby, Denmark. Marita Felder, Panterra GeoConsulting, Weversbaan 1–3, NL-2352 BZ Leiderdorp, the Netherlands. Mats Lundh Gulbrandsen, Klaus Mosegaard, Solid Earth Physics and Computational Geoscience, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen Ø, Denmark. Thomas Mejer Hansen, Solid Earth Physics and Computational Geoscience, Niels Bohr Institute, University of Copenhagen, Denmark (Now at: Institute for Geoscience, Høegh- Guldbergs Gade 2, Building 1671, 120, DK-8000 Aarhus C, Denmark). Jun-Seo Jeon, Department of Civil and Environmental Engineering, KAIST, Daejeon, 305–701, South Korea. Nicolaas Molenaar, Molenaar GeoConsulting, Paganinidreef 64, NL-2253 SK Voorschoten, the Netherlands.
Corresponding author: Ida Lykke Fabricius
Geology of the Lower Cretaceous in the Falkebjerg area, Wollaston Forland, northern East Greenland
Piasecki, S., Bojesen-Koefoed, J.A. & Alsen, P. 2020. Geology of the Lower Cretaceous in the Falkebjerg area, Wollaston Forland, northern East Greenland. Bulletin of the Geological Society of Denmark, vol. 68, pp. 155–170. ISSN 2245-7070.
https://doi.org/10.37570/bgsd-2020-68-07
Abstract
New data on the Lower Cretaceous Falskebugt Member (Palnatokes Bjerg Formation) and Stratumbjerg Formation in easternmost Wollaston Forland, northern East Greenland, are interpreted here. The type locality of the Falskebugt Member on the north-west corner of the Falkebjerg ridge has been revisited, and additional new good exposures were found in a riverbed just north of Falkebjerg and more in river beds on the plain further to the north, where both the Falskebugt Member and the Stratumbjerg Formation are exposed. Previously, only a limited marine fauna was reported providing a restricted middle Valanginian age of the Falskebugt Member. New fossil faunas in other parts of the Falskebugt Member suggest an early Valanginian – Hauterivian age and confirm lateral correlation with the Albrechts Bugt and Rødryggen Members of the Palnatokes Bjerg Formation. However, in places where the Falskebugt Member is exposed in contact with the lower Stratumbjerg Formation, dinoflagellate cysts from these units indicate Barremian and late Barremian ages, respectively. The stratigraphic range of the combined biostratigraphic data from the Falskebugt Member indicates an early Valanginian – late Barremian age. Dinoflagellate cysts from part of the assemblage in the Stratumbjerg Formation suggest a marginal marine/brackish water depositional environment. Comparable depositional environments are also recorded in upper Barremian sediments on Store Koldewey and in the Ladegårdsåen Formation on Peary Land much farther to the north in Greenland. The dark mudstones of the Stratumbjerg Formation show no potential for generation of liquid hydrocarbons, and the immature and poorly sorted sediments of the Falskebugt Member have little potential as a petroleum reservoir.
Keywords: Stratigraphy, ammonites, dinoflagellate cysts, geochemistry, Falskebugt Member, Stratumbjerg Formation, Cretaceous, East Greenland
Addresses:
Stefan Piasecki, GLOBE Institute, University of Copenhagen, Øster Voldgade 5–7, DK-1350 København, Denmark; also Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 København K, Denmark. Jørgen Bojesen-Koefoed and Peter Alsen, both Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 København K, Denmark.
Wrench-fault structures superimposed by glaciotectonic complexes, interpreted from high-resolution reflection- seismic sections and boreholes along the western bank of Esrum Sø, north-east Sjælland, Denmark
Winsløw, L.B., Pedersen, S.A.S., Boldreel, L.O. & Nørmark, E. 2020. Wrench-fault structures superimposed by glaciotectonic complexes, interpreted from high- resolution reflection-seismic sections and boreholes along the western bank of Esrum Sø, north-east Sjælland, Denmark.
Bulletin of the Geological Society of Denmark, vol. 68, pp. 171–193. ISSN 2245-7070.
https://doi.org/10.37570/bgsd-2020-68-08
Abstract
Wrench-fault structures below Danian limestone and Palaeogene marl, and an over- lying structural framework of Quaternary glacial deposits in north-east Sjælland, Denmark, are interpreted from two vibro-seismic sections recorded to 600 msec TWT depth. The main seismic section is 6.3 km long, N–S oriented, and intersected by a 0.7 km long, E–W oriented satellite seismic section. In addition, boreholes in the vicinity of the seismic profile are used for the interpretation. The sections were acquired in 2014 along the western shoreline of the lake Esrum Sø in the Gribskov area. In the lower part of the seismic section (the interval 100–300 msec TWT), parallel-bedded geological layers occur along most of the profile apart from six locations, where six wrench-fault structures displace the upper part of the Chalk Group and lower Pa- laeogene marl. The northernmost of the six wrench-fault locations correlates to the eastern slope of the buried Esrum–Alnarp valley, which suggests that the valley is an inherited tectonic feature. The location of the wrench- fault structures supports the outline of faults related to the Sorgenfrei-Tornquist Zone on previous geological maps, which had almost no seismic data from the area.
Above the stratigraphic level presented by the Danian limestone and lower Pa- laeogene marl, a composite glaciotectonic complex comprising two glaciodynamic sequences is recognized by e.g. thrust-fault structures and the lithostratigraphy of glacial successions recorded in the wells. In parts of the seismic sections, the lowermost level of the glaciotectonic complex inherited the wrench-tectonic fault structures, most significantly seen in the northern segment. The advance of the Scandinavian ice sheet caused the glaciotectonic structures displayed in the seis- mic section. The two sequences represent events related to the Norwegian and the Swedish glacial advances. From the interpretation of the seismic section it is found that the glaciotectonic complex conceals the wrench-tectonic flower structures.
Keywords: Seismic architecture, glaciotectonics, glaciodynamics, Esrum–Alnarp valley, wrench- fault tectonics, flower structures.
Addresses: Line Bayer Winsløw, Stig A. Schack Pedersen, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. Lars Ole Boldreel, Department of Geosciences and Natural Resource Management (IGN,) Copenhagen University (KU), Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. Egon Nørmark, Department of Geoscience, Aarhus University, Høegh-Guldbergs Gade 2, DK-8000 Aarhus C, Denmark.
Corresponding author: Lars Ole Boldreel.
Regional hydrocarbon potential and thermal reconstruction of the Lower Jurassic to lowermost Cretaceous source rocks in the Danish Central Graben
Schovsbo, N.H., Ponsaing, L., Mathiesen, A., Bojesen-Koefoed, J.A., Kristensen, L., Dybkjær, K., Johannessen, P., Jakobsen, F. & Britze, P. 2020. Regional hydro- carbon potential and thermal reconstruction of the Lower Jurassic to lowermost Cretaceous source rocks in the Danish Central Graben.
Bulletin of the Geological Society of Denmark, Vol. 68, pp. 195–230. ISSN 2245-7070.
https://doi.org/10.37570/bgsd-2020-68-09
Abstract
The Danish part of the Central Graben (DCG) is one of the petroliferous basins in the offshore region of north-western Europe. The source rock quality and maturity is here reviewed, based on 5556 Rock-Eval analyses and total organic carbon (TOC) measurements from 78 wells and 1175 vitrinite reflectance (VR) measurement from 55 wells, which makes this study the most comprehensive to date. The thermal maturity is evaluated through 1-D basin modelling of 46 wells. Statistical parameters describ- ing the distribution of TOC, hydrocarbon index (HI) and Tmax are presented for the Lower Jurassic marine Fjerritslev Formation, the Middle Jurassic terrestrial-paralic Bryne, Lulu, and Middle Graben Formations and the Upper Jurassic to lowermost Cretaceous marine Lola and Farsund Formations in six areas in the DCG.
For the Farsund Formation the source-rock richness is presented for selected stratigraphic sequences. The upper part of the Farsund Formation is immature in the southern part of the Salt Dome Province, and late oil mature in and near the Tail End Graben and in the Søgne Basin. The lower part of the Farsund Formation is immature in local areas, yet post-mature in the Tail End Graben and in the Salt Dome Province.
The Lower and Middle Jurassic shales are gas-prone in most of the DCG. The depth of the oil window, as defined by a VR of 0.6% Ro, ranges between 2200 and 4500 m. The variations are ascribed to heat flow differences in the DCG and can be modelled by a simple depth model, which includes the thickness of the Cretaceous to Palaeo- gene Chalk and Cromer Knoll Groups.
According to the model, a thick Chalk Group offsets the oil window to deeper levels, which likely can be attributed to the thermal properties of the highly thermally conductive chalk compared to the underlying less thermally conductive clays. The DCG is an overpressured basin, and high-pressure, high-temperature conditions are expected to occur deeper than 3.8 km except for the Feda and Gertrud Grabens where such conditions, due to generally lower tem- peratures, are expected to occur deeper than around 4.7 km.
Keywords: Danish Central Graben, Basin modelling, Jurassic source rock quality and maturation, vitrinite reflectance modelling.
Addresses: Niels Hemmingsen Schovsbo , Louise Ponsaing, Anders Mathiesen, Jørgen A. Bojesen-Koefoed, Lars Kristensen, Karen Dybkjær, Peter Johannessen, Finn Jakobsen, Peter Britze, all Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
Download PDF (5,67 Mb)Lateglacial and Holocene floras and faunas from the Salpetermosen area, north-east Sjælland, Denmark
Bennike, O., Pantmann, P. & Aarsleff, E. 2020. Lateglacial and Holocene floras and faunas from the Salpetermosen area, north-east Sjælland, Denmark.
Bulletin of the Geological Society of Denmark, vol. 68, pp. 231–244. ISSN 2245-7070.
https://doi.org/10.37570/bgsd-2020-68-10
Abstract
The Salpetermosen area in north-east Sjælland, Denmark, was deglaciated about 18 000 to 17 000 years ago. Melting of bodies of stagnant glacier ice led to the for-mation of kettle holes, which contain Lateglacial and Holocene sediments with remains of plants and animals that provide information on the past flora and fauna of the area. During the Allerød period, open forests with Betula pubescens (downy birch) characterised the area, the flora included light-demanding species such as Arctostaphylos uva-ursi (bearberry), Empetrum nigrum (crowberry) and rare Populus tremula (aspen), Betula nana (dwarf birch) and Rubus saxatilis (stone bramble), as well as the thermophilous swamp plant Oenanthe aquatica (fine-leaved water dropwort).
During the Younger Dryas, the vegetation was characterised by dwarf-shrub heaths dominated by Betula nana, but including Dryas octopetala (mountain avens), Salix herbacea (least willow), Arctostaphylos alpina (alpine bearberry,) and rare Betula pube-scens, as well as the thermophilous plants Urtica dioeca (stinging nettle) and Lychnis flos-cuculi (ragged robin).
The Early Holocene forests were dominated by Betula pubescens, Populus tremula and Pinus sylvestris (scots pine), but included rare Betula nana. Alnus glutinosa (alder) arrived at c. 10 000 cal. years BP. The calciphilous sedge Cladium mariscus (fen-sedge) and the macrolimnophyte Najas marina (spiny naiad) were common. The Late Holocene flora included the acidophilous plant Scheuchzeria palustris (rannoch-rush).
Keywords: Lateglacial, Holocene, Quaternary, vegetation history, fauna history, immigration history, Denmark, macrofossils.
Addresses: Ole Bennike [obe [at] geus [dot] dk], Geological Survey of Denmark and Greenland (GEUS), C.F. Møllers Allé 8, DK-8000 Aarhus C, Denmark. Pernille Pantmann [ppa [at] mu-seumns [dot] dk] and Esben Aarsleff [eaa [at] museumns [dot] dk], Museum Nordsjælland, Frederiksgade 11, DK-3400 Hillerød, Denmark.
Corresponding author: Ole Bennike.
Small ornithopod dinosaur tracks and crocodilian remains from the Middle Jurassic Bagå Formation, Bornholm, Denmark: Important additions to the rare Middle Jurassic vertebrate faunas of Northern Europe
Milàn, J., Falkingham, P.L. & Mueller-Töwe, I. J. 2020. Small ornithopod dinosaur tracks and crocodilian remains from the Middle Jurassic Bagå Formation, Born-holm, Denmark: Important additions to the rare Middle Jurassic vertebrate faunas of Northern Europe.
Bulletin of the Geological Society of Denmark, Vol. 68, pp. 245–253. ISSN 2245-7070.
https://doi.org/10.37570/bgsd-2020-68-11
Absract: Two new small tridactyl dinosaur tracks are found in the Middle Jurassic Bagå Formation of Bornholm and are interpreted as ornithopodian in origin. A skeletal fragment is identified as a crocodilian skull fragment. Previous finds of dinosaur tracks from the locality consist of two sizes of sauropods, a medium sized theropod and thyreophorans.
The addition of tracks from ornithopod dinosaurs and skeletal evidence of crocodilians now give a broader picture of a diverse Middle Jurassic vertebrate fauna. This is an important addition to the understanding of the terres-trial Mesozoic ecosystem of Denmark, and a valuable addition to the scarce Middle Jurassic vertebrate record of Europe.
Keywords: Dinosaur, ornithopod, crocodile, ichnology, Middle Jurassic, Bathonian, Bajocian.
Addresses: Jesper Milàn [jesperm [at] oesm [dot] dk], Geomuseum Faxe, Østsjællands Museum, Østervej 2, DK-4640 Faxe, Denmark. Peter L. Falkingham [p [dot] l [dot] falkingham [at] ljmu [dot] ac [dot] uk], School of Biological and Environmental Sciences, Liverpool John Moores University, L3 3AF, UK. Inken Juliane Mueller-Töwe [imt [at] geus [dot] dk], Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
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