Bulletin of the Geological Society of Denmark最新文献

{"title":"The importance of in situ crystallisation and loss of interstitial melt during formation of the Kærven Syenite Complex, Kangerlussuaq, East Greenland","authors":"P. Holm, Niels-Ole Prægel","doi":"10.37570/bgsd-2019-67-07","DOIUrl":"https://doi.org/10.37570/bgsd-2019-67-07","url":null,"abstract":"The Kærven Syenite Complex (KSC) is one of the oldest felsic intrusions in the Tertiary East Greenland province. Here we update our previous description of the KSC and supply a greatly expanded and comprehensive geochemical dataset. New data allow us to present a more detailed petrogenetic model for the evolution of the KSC and to investigate the geochemical characteristics of igneous cumulates subjected to loss and, occasionally, replacement of residual liquid. The KSC comprises eleven mappable units that generally young westwards. Rock types range from quartz syenite to quartz alkali feldspar syenite and alkali feldspar granite. Individual intrusive units are relatively narrow and steep-sided and are collectively suggested to represent a ring dyke complex. Basement gneiss and gabbro host rocks have locally contaminated the oldest quartz syenite KSC unit, but most of the main part of the complex escaped significant influence from host rocks. A late suite of E–W to NE–SW striking peralkaline dykes of trachytic to phonolitic compositions intrude the KSC. Compositions of the KSC rocks span a considerable range in SiO2, 59–73 wt%. Concentrations of several elements vary widely for a given SiO2 (especially at SiO2 < 66 wt%), and variation diagrams do not suggest a single model for the evolution of the units of the complex. A cumulative origin is envisaged for several KSC units. Geochemical modelling suggests that KSC magmas were derived from more than one primary magma, and that the complex evolved through a four-stage process: fractional crystallisation in precursory magma chambers was followed by final emplacement of each unit, establishment of a crystal/melt mush, expulsion of part of the residual melt and, finally, crystallisation of the remaining melt. Trace element disequilibria between alkali feldspar and host rocks in two closely associated quartz alkali feldspar syenite units indicate that highly evolved residual melt was replaced by a less evolved melt phase. Modelling of potential parent melt compositions to the Kærven magmas suggests an origin not in the Iceland plume asthenosphere, but rather in a moderately enriched source, possibly in the continental lithosphere. The course of melt evolution by fractional crystallisation is indicated to have taken place in magma chambers at depth, and repeated rise of magma into the upper crustal magma chambers and crystallisation there formed the KSC. Based on our survey of published geochemical data, the inferred parental magmas seem to have few equivalents in the North Atlantic Igneous Province and may have been generated mainly from melting of enriched dry lithospheric mantle of possibly Archaean age.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44356909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lateglacial and Holocene floras and faunas from the Salpetermosen area, north-east Sjælland, Denmark","authors":"O. Bennike, P. Pantmann, Esben Aarsleff","doi":"10.37570/bgsd-2020-68-10","DOIUrl":"https://doi.org/10.37570/bgsd-2020-68-10","url":null,"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).\u0000During 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).\u0000The 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).","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45421396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ordovician gastropods from pebbles in Cretaceous fluvial\u0000sandstones in south-east Disko, West Greenland","authors":"J. S. Peel","doi":"10.37570/bgsd-2019-67-05","DOIUrl":"https://doi.org/10.37570/bgsd-2019-67-05","url":null,"abstract":"The gastropods Sinuopea sp. and Lecanospira cf. compacta (Salter 1859) of probable early Ordovician age are described from cherty limestone clasts within fluvial strata of the Cretaceous Atane Form ...","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47847894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regional hydrocarbon potential and thermal reconstruction of the Lower Jurassic to lowermost Cretaceous source rocks in the Danish Central Graben","authors":"N. Schovsbo, L. Ponsaing, A. Mathiesen, J. Bojesen‐Koefoed, L. Kristensen, K. Dybkjær, P. Johannessen, F. Jakobsen, B. Peter","doi":"10.37570/BGSD-2020-68-09","DOIUrl":"https://doi.org/10.37570/BGSD-2020-68-09","url":null,"abstract":"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. Bulletin of the Geological Society of Denmark, Vol. 68, pp. 195–230. ISSN 2245-7070. https://doi.org/10.37570/bgsd-2020-68-09","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46388996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"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","authors":"Line Bayer Winslow, S. Pedersen, L. O. Boldreel, E. Nørmark","doi":"10.37570/bgsd-2020-68-08","DOIUrl":"https://doi.org/10.37570/bgsd-2020-68-08","url":null,"abstract":"Wrench-fault structures below Danian limestone and Palaeogene marl, and an overlying\u0000structural framework of Quaternary glacial deposits in north-east Sjælland,\u0000Denmark, are interpreted from two vibro-seismic sections recorded to 600 msec TWT\u0000depth. The main seismic section is 6.3 km long, N–S oriented, and intersected by a 0.7\u0000km long, E–W oriented satellite seismic section. In addition, boreholes in the vicinity\u0000of the seismic profile are used for the interpretation. The sections were acquired in\u00002014 along the western shoreline of the lake Esrum Sø in the Gribskov area. In the\u0000lower part of the seismic section (the interval 100–300 msec TWT), parallel-bedded\u0000geological layers occur along most of the profile apart from six locations, where six\u0000wrench-fault structures displace the upper part of the Chalk Group and lower Palaeogene\u0000marl. The northernmost of the six wrench-fault locations correlates to the\u0000eastern slope of the buried Esrum–Alnarp valley, which suggests that the valley is\u0000an inherited tectonic feature. The location of the wrench- fault structures supports\u0000the outline of faults related to the Sorgenfrei-Tornquist Zone on previous geological\u0000maps, which had almost no seismic data from the area.\u0000Above the stratigraphic level presented by the Danian limestone and lower Palaeogene\u0000marl, a composite glaciotectonic complex comprising two glaciodynamic\u0000sequences is recognized by e.g. thrust-fault structures and the lithostratigraphy\u0000of glacial successions recorded in the wells. In parts of the seismic sections, the\u0000lowermost level of the glaciotectonic complex inherited the wrench-tectonic fault\u0000structures, most significantly seen in the northern segment. The advance of the\u0000Scandinavian ice sheet caused the glaciotectonic structures displayed in the seismic\u0000section. The two sequences represent events related to the Norwegian and the\u0000Swedish glacial advances. From the interpretation of the seismic section it is found\u0000that the glaciotectonic complex conceals the wrench-tectonic flower structures.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41286465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the occurrence of Spinucella reimersi (von Koenen 1872) (Gastropoda: Muricidae) in the Late Miocene Gram Clay of Denmark, and an emended description of the species","authors":"Kai Ingemann Schnetler","doi":"10.37570/bgsd-2019-67-02","DOIUrl":"https://doi.org/10.37570/bgsd-2019-67-02","url":null,"abstract":"Spinucella reimersi in the Late Miocene Gram Clay, Denmark The mica-rich clay at Gram in southern Denmark (Fig. 1) has been known since 1848, and digging of a pit for brick-making started after 1857 (L.B. Rasmussen 1968, p. 10). The collecting of molluscs started soon thereafter, and Semper (1861) studied material from Gram. Further studies in the second half of the 19th century, including material from Gram, were made by von Koenen (1872, 1882) and Mörch (1874). A description of the geological setting of the Gram Clay is found in E.S. Rasmussen (2005). For further references to the fauna, see Schnetler (2005). The physician Martin Reimers started as a general practitioner in Gram in 1841 and was a keen and skillful collector of fossils in the clay pit; without doubt this caught the interest of the professional palaeontologists. Carinastarte vetula reimersi (Ravn 1907), the most common mollusc species in the Gram Clay, was named in honour of Martin Reimers by Semper in an unpublished manuscript. The present study describes Martin Reimers’ connection to a very rare and almost neglected gastropod species, Spinucella reimersi, which since the first finding in 1862 has only been encountered twice. Furthermore, two new specimens have allowed an emended description of the species.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44377145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tectonostratigraphy and evolution of the West Greenland continental margin","authors":"U. Gregersen, P. Knutz, H. Nøhr-Hansen, E. Sheldon, J. Hopper","doi":"10.37570/bgsd-2019-67-01","DOIUrl":"https://doi.org/10.37570/bgsd-2019-67-01","url":null,"abstract":"Large structural highs and sedimentary basins are identified from mapping of the West Greenland continental margin from the Labrador Sea to the Baffin Bay. We present a new tectonic elements map and a map of thickness from the seabed to the basement of the entire West Greenland margin. In addition, a new stratigraphic scheme of the main lithologies and tectonostratigraphy based on ties to all offshore exploration wells is presented together with seven interpreted seismic sections. The work is based on interpretation of more than 135 000 km of 2D seismic reflection data supported by other geophysical data, including gravity- and magnetic data and selected 3D seismic data, and is constrained by correlation to wells and seabed samples. Eight seismic mega-units (A–H) from the seabed to the basement, related to distinct tectonostratigraphic phases, were mapped. The oldest units include pre-rift basins that contain Proterozoic and Palaeozoic successions. Cretaceous syn-rift phases are characterised by development of large extensional fault blocks and basins with wedge-shaped units. The basin strata include Cretaceous and Palaeogene claystones, sandstones and conglomerates. During the latest Cretaceous, Paleocene and Eocene, crustal extension followed by oceanic crust formation took place, causing separation of the continental margins of Greenland and Canada with north-east to northward movement of Greenland. From Paleocene to Eocene, volcanic rocks dominated the central West Greenland continental margin and covered the Cretaceous basins. Development of the oceanic crust is associated with compressional tectonics and the development of strike-slip and thrust faults, pull-apart basins and inversion structures, most pronounced in the Davis Strait and Baffin Bay regions. During the late Cenozoic, tectonism diminished, though some intra-plate vertical adjustments occurred. The latest basin development was characterised by formation of thick Neogene to Quaternary marine successions including contourite drifts and glacial related shelf progradation towards the west and south-west.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46937287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shallow subsurface thermal structure onshore Denmark: temperature, thermal conductivity and heat flow","authors":"I. Møller, N. Balling, C. Ditlefsen","doi":"10.37570/bgsd-2019-67-03","DOIUrl":"https://doi.org/10.37570/bgsd-2019-67-03","url":null,"abstract":"Shallow subsurface thermal structure onshore Denmark Subsurface temperatures and thermal properties are important factors in controlling the amount of thermal energy that can be extracted or stored in the ground. Local and regional variations in the thermal conditions affect the design and efficiency of shallow geothermal installations, especially when heat pumps are applied (Rasmussen et al. 2016; Sanner 2016). Thus, knowledge about temperature, subsurface thermal properties as well as heat flow are required for estimating geothermal resources and in evaluating methodologies for heat extraction. In contrast to deep geothermal conditions (cf. Balling et al. 1992, 2002; Mathiesen et al. 2009, 2010), until the present study, the shallow subsurface thermal conditions in Denmark have not been analysed on a national scale. The first borehole temperatures were measured around 1900 as accurate bottom hole temperatures (Bonnesen et al. 1913) while the, at the time, deepest Shallow subsurface thermal structure onshore Denmark: temperature, thermal conductivity and heat flow","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47775595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geology of the Lower Cretaceous in the Falkebjerg area, Wollaston Forland, northern East Greenland","authors":"S. Piasecki, J. Bojesen‐Koefoed, P. Alsen","doi":"10.37570/bgsd-2020-68-07","DOIUrl":"https://doi.org/10.37570/bgsd-2020-68-07","url":null,"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.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46252125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The feasibility of high-temperature aquifer thermal energy storage in Denmark: the Gassum Formation in the Stenlille structure","authors":"Lisa Pasquinelli, M. Felder, M. Gulbrandsen, T. Hansen, Jun-Seo Jeon, N. Molenaar, K. Mosegaard, I. Fabricius","doi":"10.37570/bgsd-2020-68-06","DOIUrl":"https://doi.org/10.37570/bgsd-2020-68-06","url":null,"abstract":"Heat storage in the Danish subsurface is gaining increasing interest for optimizing\u0000the use of energy resources, but no deep heat storage facilities have yet been\u0000established. As an analogue we study the Gassum Formation in the Stenlille\u0000structure that is presently used for gas storage. This allows us to discuss geological\u0000and technical characteristics of an aquifer relevant for heat storage in Denmark.\u0000We develop a 3D model for a high-temperature aquifer thermal energy storage system\u0000using analysis of geological core data, sedimentological description, geophysical\u0000data including well logs and seismic lines, as well as a finite difference model to\u0000calculate the recovery efficiency, heat storage capacity and thermal breakthrough\u0000time. Based on geostatistical methods we made three realisations and found similar\u0000results for the three cases. In accordance with results from published simplified\u0000models we found a high recovery efficiency of 70% after 4 years and 69% after 20\u0000years, a high heat storage capacity of 1.8×1018 J, and a long thermal breakthrough\u0000time of 66–77 years. These results reflect the excellent reservoir properties of the\u0000Gassum Formation in Stenlille, characterised by a uniformly layered sand/shale\u0000sedimentology, a high average porosity of 25% and a high permeability of 1000 to\u000010 000 mD of sandstone intervals.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42758397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}