Publikationer

Abstract: A rich late Oligocene molluscan fauna from a coastal cliff at Vilsund on the island of Mors, Jylland, Denmark, was studied. A summary of the upper Palaeogene sedimentary sequence in NW Jylland is given and lithostratigraphical and biostratigraphical correlations are suggested. The molluscan fauna contains 120 species, and the nonmolluscs are briefly mentioned. The new species Mitromorpha (Mitrolumna) danica n. sp. and Cerithiopsis vilsundensis n. sp. are established. Mitromorpha (Mitrolumna) danica n. sp. is the first representative of the gastropod genus Mitromorpha Carpenter, 1865 and subgenus Mitrolumna Bucquoy, Dautzenberg & Dollfus, 1883 from the Cenozoic of Denmark. Eubela (s. lat.) zetes (Kautsky, 1925) represents the oldest record of the genus Eubela Dall, 1889. Andersondrillia Schnetler & Beyer, 1990 is considered to be a junior synonym of Benthomangelia Thiele, 1925. The bivalve genus Cubiostrea Sacco, 1897 is recorded from the upper Oligocene of the North Sea Basin for the first time. In the systematical part, several species are treated, including 16 species which have not been recorded previously from the Danish upper Oligocene; a synopsis of the representatives of the genus Streptodictyon Tembrock, 1961 in the Danish Oligocene is also given. Aphanitoma ingerae Schnetler & Palm, 2008 is transferred to the genus Mitromorpha, subgenus Mitrolumna. The fauna is compared with other Danish and German late Oligocene faunas and palaeoecological interpretations are suggested.
As many of the mollusc species have not previously been illustrated from the Dan– ish upper Oligocene, the fauna is extensively illustrated.
      Dinocyst assemblages have been studied to help date the investigated successions. The assemblages indicate that the glauconitic clay from Vilsund should be assigned to the provisionally named stratigraphical Unit X in Śliwińskaet al. (2012) or the lowermost Brejning Formation. Unit X was previously only known from the interval 61.5–67.5 m in the Harre-1 borehole. Schnetler & Beyer (1990) assigned the glauconitic clay in the coastal cliff at Mogenstrup to the Brejning Formation, but dinocyst studies herein indicate that these strata should be assigned either to Unit X, most likely the upper part, or the lowermost Brejning Formation (see Appendix). This interpretation is supported by the foraminifers and the pectinid species Palliolum hausmanni (Goldfuss, 1835).
      The occurrence of other nearby outcrops of differing Oligocene ages is demonstrated. The outcrops are described and dated by means of dinocysts and foraminifers and include a section showing a depositional contact between the lowermost Rupelian Viborg Formation and Chattian Branden Clay. The age of the Mogenstrup section is also demonstrated by means of dinocysts.

Keywords: Mollusca, taxonomy, biostratigraphy, dinocysts, palaeontology, Brejning Formation, Viborg Formation, Oligocene, Denmark, North Sea Basin.

Address: Kai Ingemann Schnetler [ingemann [at] schnetler [dot] dk], Fuglebakken 14, Stevnstrup, DK-8870 Langå, Denmark. Henrik Madsen [henrik [dot] madsen [at] museummors [dot] dk], Fossil and Moclay
Museum, Museum Mors, Skarrehagevej 8, Nykøbing Mors, DK-7900, Denmark. Kasia K. Śliwińska [kksl [at] geus [dot] dk], Department of Geo-energy and Storage, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. Claus Heilmann-Clausen [claus [dot] heilmann [at] geo [dot] au [dot] dk], Department of Geoscience, Aarhus University, DK-8000 Aarhus, Denmark. Kaare Ulleberg [ka-ulleb [at] online [dot] no], Kløverstien 7, N-3074 Sande (Vestfold), Norway.

Abstract: Serpulid remains are very rare in the Lower Jurassic Hasle Formation of Bornholm, Denmark. A historical specimen mentioned, but not figured by Malling & Grön wall (1909) was reexamined and attributed to Pentaditrupa quinquesculcata and here f igured for the first time. New finds of additional well-preserved serpulid tubes are described as Serpula? alicecooperi sp. nov, which show adaptations for a lifestyle on fine-grained sediment in a nearshore environment.

Keywords: Early Jurassic, Pliensbachian, Serpula, Pentaditrupa, Bornholm, Denmark.

Address: Tomáš Kočí [protula [at] seznam [dot] cz], Ivančická 581, Prague 9 – Letňany, 19900, Czechia, and Palaeontological Department, Natural History Museum, National Museum, Cirkusová 1740, 193 00 Praha 20 – Horní Počernice, Czechia. Jesper Milàn [jesperm [at] oesm [dot] dk], Geo museum Faxe/Østsjællands Museum, Østervej 2, DK-4640 Faxe, Denmark. Sten Lennart Jakobsen [stenlennart [at] yahoo [dot] dk], Geomuseum Faxe/Østsjællands Museum, Østervej 2, DK-4640 Faxe, Denmark. Arden R. Bashfort [bashforth [at] snm [dot] ku [dot] dk], Natural History Museum of Denmark, Øster Voldgade 5-7, DK-1350 København K, Denmark.

Abstract: Borings of microscopic organisms (euendoliths) are described from the Henson Gletscher Formation (middle Cambrian, Miaolingian Series, Wuliuan Stage) of Peary Land, North Greenland (Laurentia). Partially phosphatised sclerites of Chancelloria and valves of the brachiopod Nisusia reveal abundant casts of borings following dissolution of skeletal calcium carbonate in weak acetic acid. Threads referred to Scolecia dominate, occurring together with coccoids (Planobola) and the branching Fascichnus, in a suite comparable to a lower Cambrian assemblage from the Maidiping Formation of Sichuan, China.

Keywords: Euendoliths, Chancelloria spicules, Nisusia, Cambrian (Miaolingian Series, Wuliuan Stage), North Greenland, Laurentia.

Address: John S. Peel [john [dot] peel [at] pal [dot] uu [dot] se], Department of Earth Sciences (Palaeobiology), Uppsala University, Villavägen 16, SE-75236 Uppsala, Sweden.

Neotectonic deformations of the lakebeds in Esrum Sø, eastern Denmark, interpreted to indicate a Postglacial pull-apart basin. 

Abstract: From 1995 to 2022, several expeditions have visited the small Ikka fjord in SW Greenland to study growth and stability of the more than 1000 submarine tufa columns build of the metastable, cold-water carbonate ikaite (CaCO₃·6H₂O). The different water types in the area have been sampled for geochemical and stable isotope (²H and ¹⁸O) investigations. Here we present the results of more than 300 isotope analyses of water from the fjord and from streams, lakes, springs and tufa columns. Fjord water samples identify a two-component mixing system (R² > 0.99) between freshwater runoff and sea water entering from the Davis Strait. The fresh water samples have an average composition of –95.4‰ δ²H and –13.1‰ δ¹⁸O. We f ind both seasonal and altitude effects in fresh water related to early (June–July) or late (August) sampling time. All freshwater samples excluding lakes but including previous precipitation data (GNIP, 1963–1974) can be described by a Local Meteoric Water Line with slope of 6.43 ± 0.12 and offsets between 6.34 and 6.56. Column water samples are mixed with fjord water but extrapolation to a chlorine-free composition defines an endmember composition of –102‰ δ²H and –14.2‰ δ¹⁸O. These composi tions identify precipitation on top of the igneous plateau at ~ 500 m altitude as the source for the column water.

Keywords: Hydrogen and oxygen isotopes, meteoric water, fjord water, tufa columns, Ikka fjord, SW Greenland.

Address: Bjørn Buchardt [bjorn [dot] buchardt [at] mail [dot] dk], Overgaden neden Vandet 5A,1.tv., DK-1414, Copenhagen K, Denmark. Gabrielle Stockmann [gabrielle [at] hi [dot] is], Jarvik Geoconsulting AB, Gothenburg, Sweden and Department of Earth Sciences, University of Iceland, Reykjavik, Iceland. Marc O. Hansen [marcowater [at] yahoo [dot] com], Danish Nature Agency, DK-4500, Nykøbing Sjælland, Denmark. Árný Sveinbjörnsdóttir [arny [at] hi [dot] is], Institute of Earth Sciences, University of Iceland, Reykjavik, Iceland.

Characteristics and formation of natural fractures in a silica-rich chalk, Coniacian Arnager Limestone Formation, Bornholm, Denmark.