Bulletin Volume 73 – 2024

Contents

Schnetler, K.I., Madsen, H., Śliwińska, K.K., Heilmann-Clausen, C. & Ulleberg, K. 2024. A late Oligocene molluscan fauna and Oligocene coastal outcrops from Vilsund, NW Denmark.

Kočí, T., Milàn, J., Jakobsen, S.L. & Bashforth, A.R. 2024. Serpula? alicecooperi sp. nov. – a new serpulid from the Lower Jurassic (Pliensbachian) Hasle Formation of Bornholm, Denmark.

Peel, J.S. 2024. Euendolith borings in Chancelloria and Nisusia from the middle Cambrian (Miaolingian) of North Greenland (Laurentia).

Boldreel, L.O. & Pedersen, S.A.S. 2024. Neotectonic deformations of the lakebeds in Esrum Sø, eastern Denmark, interpreted to indicate a Postglacial pull-apart basin.

Schrøder, A.E. & Surlyk, F. 2024. The cancellothyridid brachiopod Terebratulina chrysalis from the Selandian Kerteminde Marl at Gundstrup, Denmark.

Schwarzhans, W.W. & Nielsen, K.A. 2024. Fish otoliths from the bathyal Eocene Lillebælt Clay Formation of Denmark.

Schwarzhans, W.W., Nielsen, K.A. & Schnetler, K.I. 2024. Fish otoliths from the basal Oligocene Viborg Formation in Denmark.

 

A late Oligocene molluscan fauna and Oligocene coastal outcrops from Vilsund, NW Denmark

Schnetler, K.I., Madsen, H., Śliwińska, K.K., Heilmann-Clausen, C. & Ulleberg, K. 2024. A late Oligocene molluscan fauna and Oligocene coastal outcrops from Vilsund, NW Denmark.
Bulletin of the Geological Society of Denmark, Vol. 73, pp. 1–40.
ISSN 2245-7070. https://doi.org/10.37570/bgsd-2024-73-01

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 Danish 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.

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Serpula? alicecooperi sp. nov. – a new serpulid from the Lower Jurassic (Pliensbachian) Hasle Formation of Bornholm, Denmark

Kočí, T., Milàn, J., Jakobsen, S.L. & Bashforth, A.R. 2024. Serpula? alicecooperi sp. nov. – a new serpulid from the Lower Jurassic (Pliensbachian) Hasle Formation of Bornholm, Denmark.
Bulletin of the Geological Society of Denmark, Vol. 73, pp. 41–56.
ISSN 2245-7070. https://doi.org/10.37570/bgsd-2024-73-02

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.

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Euendolith borings in Chancelloria and Nisusia from the middle Cambrian (Miaolingian) of North Greenland (Laurentia). 

Peel, J.S. 2024. Euendolith borings in Chancelloria and Nisusia from the middle Cambrian (Miaolingian) of North Greenland (Laurentia).
Bulletin of the Geological Society of Denmark, Vol. 73, pp. 57–66.
ISSN 2245-7070. https://doi.org/10.37570/bgsd-2024-73-03

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.

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

Boldreel, L.O. & Pedersen, S.A.S. 2024. Neotectonic deformations of the lakebeds in Esrum Sø, eastern Denmark, interpreted to indicate a Postglacial pull-apart basin.
Bulletin of the Geological Society of Denmark, Vol. 73, pp. 67–88.
ISSN 2245-7070. https://doi.org/10.37570/bgsd-2024-73-04

Abstract: Esrum Sø, with a marked elongation trending N–S, located in the glaciomorphological landscape of north-eastern Sjælland, is one of the biggest lakes in Denmark. The lake is shaped as a large ‘sink’ with steep sides and a maximum depth of c. 22 m. The present investigation and mapping of the structures of the lakebeds is based on the interpretation of 10 reflectors on 82 acquired high-resolution seismic sections (Chirp III) and correlation to the 8.5 m long Esrum Sø drill core in the northern part of Esrum Sø.
A new formation, the Esrum Formation, with two members, the Fredensborg and Nødebo Members, is erected based on the geological information obtained from the drill core, and traced on the seismic sections over the major part of Esrum Sø. In the northern part of the lake, the seismic sections reveal a number of anti- and synform structures, which we group into five architectural features. The mapping of these structures show N–S trending vertical fractures, fault scarps and fold crests, which in places are bent towards a NW direction. In some, mainly southern,
parts of the lake, gas stored in the gyttja (Nødebo Member) and close to the lake floor degrades the seismic signal significantly. The gas is ascribed to seepage and production close to the lake floor. The integration of the seismic interpretation and the Esrum Sø drill core data shows that the Young Baltic till constitutes the base of the depression where Esrum Sø is located. In Bølling to Preboreal time the Esrum Sø was a shallow freshwater lake with no tectonic activity (Fredensborg Member), and the major deformation and subsidence of the lake basin took place in Boreal to
Atlantic time (Nødebo Member). Our interpretation favours a model of a Postglacial pull-apart basin related to extension in the wrench-fault tectonic zone aligned with the Sorgenfrei–Tornquist Zone.

Keywords: High-resolution shallow seismic data, wrench-fault tectonics, extensional fractures, calcareous gyttja, shallow gas, Esrum Sø Formation.

Address: Lars Ole Boldreel [lob [at] ign [dot] ku [dot] dk], Department of Geosciences and Natural Resource Management, Geology Section, University of Copenhagen, Øster Voldgade 10, DK-1350
Copenhagen K, Denmark. Stig A. Schack Pedersen [sasp [at] geus [dot] dk], Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.

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The cancellothyridid brachiopod Terebratulina chrysalis from the Selandian Kerteminde Marl at Gundstrup, Denmark. 

Schrøder, A.E. & Surlyk, F. 2024. The cancellothyridid brachiopod Terebratulina chrysalis from the Selandian Kerteminde Marl at Gundstrup, Denmark.
Bulletin of the Geological Society of Denmark, Vol. 73, pp. 89–98.
ISSN 2245-7070. https://doi.org/10.37570/bgsd-2024-73-05

Abstract: The articulate brachiopod Terebratulina chrysalis is very common in the Upper Cretaceous chalk of northern Europe and in the Danian chalk, bryozoan limestone and coralline-bryozoan limestone mounds of Denmark. It was one of the few brachiopod species that survived the mass extinction at the Cretaceous–Palaeogene boundary and it belongs to a long-lived group of closely related Cretaceous–Recent species. It represents a non-specialised generalist which with a rootlike pedicle was able to attach itself to a great variety of both hard and soft substrates. The great adaptability is probably the main reason for its evolutionary success. This is the first systematic study concerning brachiopods from the Kerteminde Marl Formation in Denmark. Hitherto Terebratulina chrysalis is the only known brachiopod from the Gundstrup blocks, referred to the Kerteminde Marl.

Keywords: Brachiopoda, rootlet pedicle, Cancellothyrididae, Paleocene, Gundstrup gravel pit.

Address: Ane Elise Schrøder [aes [at] ign [dot] ku [dot] dk], Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen K, Denmark; also Dipartimento di Scienze della Terra, Università degli Studi di Torino, Via Valperga Caluso 35, I-10125 Torino, Italy. https://orcid.org/0000-0001-9371-400X. Finn Surlyk [finns [at] ign [dot] ku [dot] dk], Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen K, Denmark.

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Fish otoliths from the bathyal Eocene Lillebælt Clay Formation of Denmark. 

Schwarzhans, W.W. & Nielsen, K.A. 2024. Fish otoliths from the bathyal Eocene Lillebælt Clay Formation of Denmark.
Bulletin of the Geological Society of Denmark, Vol. 73, pp. 99–111.
ISSN 2245-7070. https://doi.org/10.37570/bgsd-2024-73-06

Abstract: Few deepwater otolith associations from the Eocene have been found so far. The small assemblage of aragonitic-preserved otoliths from the Lillebælt Clay Formation described here therefore adds to the understanding of early Palaeogene deep-sea fish faunas. These otoliths were obtained from a level at about the Ypresian/Lutetian interface and may thus be older than the otoliths previously described from Trelde Næs from mold casts from carbonate concretions. Only 14 otoliths were recovered from about 6,000 kg processed bulk samples. The assemblage also differs in the composition and contains three new species and one new genus: Diaphus? duplex n. sp., Bregmaceros danicus n. sp. and the ophidiid Pronobythites schnetleri n. gen, n. sp. In addition, the new genus Treldeichthys n. gen. in Acanthomorpha incertae sedis is established for T. madseni (Schwarzhans, 2007). The small assemblage also differs in composition from comparable associations described from southwest France and northern Italy on the species level but shows some relationship on a higher systematic level. The mechanism and timing of the colonization of the deep sea by selected groups of fishes is discussed, particularly in respect to the depth migration of demersal fishes.

Keywords: otoliths, Eocene, Denmark, new species, Trelde Næs, deepwater colonization.

Address: Werner W. Schwarzhans [wwschwarz [at] aol [dot] com], Zoological Museum, Natural History
Museum of Denmark, Universitetsparken 15, 2100 Copenhagen Ø, Denmark and Ahrensburger Weg 103, 22359 Hamburg, Germany, http://orcid.org/0000-0003-4842-7989. Kent A. Nielsen [kent [at] ksjm [dot] dk], Tingskoven 22, DK-7330 Brande, Denmark, https://
orcid.org/0000-0002-5800-5774.

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Fish otoliths from the basal Oligocene Viborg Formation in Denmark. 

Schwarzhans, W.W., Nielsen, K.A. & Schnetler, K.I. 2024. Fish otoliths from the bathyal Eocene Lillebælt Clay Formation of Denmark.
Bulletin of the Geological Society of Denmark, Vol. 73, pp. 113–133.
ISSN 2245-7070. https://doi.org/10.37570/bgsd-2024-73-07

Abstract: The Viborg Formation is the lowest part of the early Oligocene in Denmark and represents the upper part of nannoplankton zone NP21. Here we describe a small assemblage of otoliths from the Viborg Formation obtained from five localities that yielded 88 specimens of nine species. The composition of the otolith-based fish species is transitional between the terminal Eocene (Priabonian) faunas from the Latdorf Formation of northern Germany and its equivalents and the middle and upper Rupelian. The Viborg otolith association witnessed the first arrivals of the subsequently dominant Gadidae (Trisopterus elegans) and the migration of certain species of the merlucciid genus Palaeogadus from the Eastern Paratethys through the Polish gateway. Furthermore, the otoliths from the Viborg Formation fill an important gap in the previous knowledge of late Eocene and early Oligocene otolith associations in the North Sea Basin and thus facilitate some refinement of their biostratigraphic usage.

Keywords: otoliths, lower Oligocene, Viborg Formation, Denmark, otolith stratigraphy, palaeobiogeography.

Address: Werner W. Schwarzhans [wwschwarz [at] aol [dot] com], Zoological Museum, Natural History
Museum of Denmark, Universitetsparken 15, 2100 Copenhagen Ø, Denmark, and Ahrens burger Weg 103, 22359 Hamburg, German, http://orcid.org/0000-0003-4842-7989. Kent A. Nielsen [kent [at] ksjm [dot] dk], Tingskoven 22, DK -7330 Brande, Denmark, https://orcid. org/0000-0002-5800-5774; Kai Ingemann Schnetler [ingemann [at] schnetler [dot] dk], Fuglebakken 14, Stevnstrup, DK – 8870 Langå, Denmark, https://orcid.org/0009-0000-2298-2875.

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