Publikationer

Continuous record of Holocene sea-level changes and coastal development of the Kattegat island Læsø (4900 years BP to present)

Hansen, J.M., Aagaard, T., Stockmarr, J., Møller, I., Nielsen, L., Binderup, M., Larsen, J.H. & Larsen, B.2016-01-29. Continuous record of Holocene sea-level changes and coastal development of the Kattegat island Læsø (4900 years BP to present).
© 2016 by Bulletin of the Geological Society of Denmark,

Vol. 64, pp. 1–55. ISSN 2245-7070. (www.2dgf.dk/publikationer/bulletin).
https://doi.org/10.37570/bgsd-2016-64-01

Abstract: Læsø is the largest island of the Kattegat–Skagerrak region and exposes a vast array of relative sealevel (RSL) indicators, mainly raised beach ridges, swales, lagoons and saltmarshes.

The physical environment of continuous glacial rebound, excessive supply of sediment, shallow surrounding waters, low amplitudes of near-shore waves, and micro-tidal conditions produced numerous sealevel proxies of both barrier coasts and saltmarshes. About 1200 RSL/age index points reflect not only short-term sea-level highstands as in most other parts of Europe, but also short-erm sea-level lowstands, which in less regressive environments have normally been removed by coastal erosion or obscured by berms from subsequent highstands.

Based on a high-precision lidar digital terrain model, the beach ridges have been mapped, typified, levelled and correlated relative to their order of appearance. Transformation of this relative chronology to a robust absolute age model of the RSL changes has been made on the basis of 119 optically stimulated luminescence (OSL) datings, 14C datings, and tree-ring datings.

By ground penetrating radar (GPR) and terrain analyses, the height of the swash zone (run-up) has been determined in order to transform the ridge elevations to a detailed curve of the RSL/age relation. The curve reveals eight centennial sea-level oscillations of 0.5–1.1 m superimposed on the general trend of the RSL curve, including a Little Ice Age lowstand of 0.6 m at 1300 AD. The island grew from now eroded landscapes of Weichselian glacio-marine deposits, including the oldest known post-Weichselian forested area in Scandinavia.

During the last 4900 years new coastal landscapes have formed continuously, resulting in around 4000 km of still visible, raised palaeo-shorelines in mostly uncultivated landscapes. After formation of the oldest preserved beach-ridge complex, numerous sea-level proxies formed in a strongly regressive environment caused by glacial rebound supplemented with local uplift due to extensive erosion during Boreal and Atlantic time of the 1700 km2 glacio-marine platform upon which the island is still being built.

The combined uplift produced a relative sea-level fall of 10.3 m, corresponding to a mean vertical regression rate of 2.1 mm/year and a mean horizontal regression rate of 2 m/year, and formed eight distinct types of raised coastal landscapes where well separated beach ridges and saltmarshes developed continuously.
The oldest preserved part of Læsø appeared 4900 years BP as the eastern tip of a 10 km long barrier-spit system growing from a raised glacio-marine landscape, now represented only by boulder reefs west and north-west of the present island.

Around 4000 years BP another barrier-spit system appeared to the south, growing northwards from another raised glacio-marine landscape at the raised boulder reefs in the town of Byrum and the abrasion landscapes of Rønnerne.

Around 3000 years BP these two inital barrier-spit systems united and formed one major barrier between the present towns Vesterø and Byrum. To the north-east, a third glacio-marine landscape provided materials for the development of the eastern end of the island. Thus, around 2500 BP the island had become one triangular, completely detached island (’the old triangle’) between Vesterø, Byrum and Bansten Bakke. From this detached stage, nine subsequent barrier-spit systems grew to the east and formed the present Østerby peninsula, while a series of nine barrier-island complexes developed south-west of ’the old triangle’. To the south and south-east, low-energy coasts developed and formed low beach ridges and saltmarsh landscapes.

Keywords: Læsø, Holocene, beach ridge, relative sea-level curve, isostatic rebound, Lidar DTM, optically stimulated luminescence (OSL) dating.

Addresses:
Jens Morten Hansen [jmh [at] geus [dot] dk ], Jens Stockmarr [sto [at] geus [dot] dk], Ingelise Møller, Merete Binderup, Birger Larsen, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
Troels Aagaard [taa [at] ign [dot] ku [dot] dk], Lars Nielsen [ln [at] ign [dot] ku [dot] dk], Department of Geosciences and Natural Resource Management, Copenhagen University, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
Jan Hammer Larsen [jhl [at] kystmuseet [dot] dk], Coastal Museum of Northern Jutland, Bangsbo Division, Dronning Margrethesvej 6, 9900 Frederikshavn, Denmark.

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Distribution and significance of foraminiferal biofacies on an aphotic Danian bryozoan mound, Karlstrup, Denmark

Springer, E.G., Rasmussen, J.A. & Stemmerik, L. 2016-04-12. Distribution and significance of foraminiferal biofacies on an aphotic Danian bryozoan mound, Karlstrup, Denmark.
© 2016 by Bulletin of the Geological Society of Denmark, Vol. 64, pp. 57-67. ISSN 2245-7070. (www.2dgf.dk/publikationer/bulletin).
https://doi.org/10.37570/bgsd-2016-64-02

Abstract: In this study, the distribution of benthic foraminifers across a Danian bryozoan mound in Karlstrup quarry, Denmark, is analysed in 22 samples using multivariate analysis. Three foraminiferal biofacies are established, each representing a distinct part of the mound.
The Anomalinoides-Cibicides- Osangularia Biofacies is characteristic of the relatively pure carbonate sediments on the crest and flanks of the bryozoan mound. The Patellina Biofacies occurs at the mound flanks and is particularly common in marly sediments. The Spirillina Biofacies characterises the crest of the bryozoan mound in both marly and pure carbonate sediments.

Variations in the plankton/benthos ratio indicate that the benthic foraminifers prefer the marly sediments to pure limestone and mound flanks relative to the mound top. It is likely that the benthic foraminifers avoided the more powerful currents at the mound crest. The common occurrence of spirillinids on the mound top may represent the remnant of a rich, siliceous sponge community.

Keywords: Palaeoecology, benthic foraminifers, biofacies, Danian, Karlstrup quarry, bryozoan mounds.

Addresses:
Emilie Grønbæk Springer [emiliegspringer [at] gmail [dot] com], Gentofte Kommune, Natur og Miljø, Bernstorffsvej 161, DK-2920 Charlottenlund, Denmark.
Jan Audun Rasmussen [janr [at] snm [dot] ku [dot] dk ] and Lars Stemmerik [stemmerik [at] snm [dot] ku [dot] dk“>lars. stemmerik [at] snm [dot] ku [dot] dk], Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5–7, DK-1350 Copenhagen K, Denmark.
JAR from April 1st 2016: Museum Mors/Fossil and Mo-clay Museum, Skarrehagevej 8, DK-7900 Nykøbing Mors, Denmark.
Corresponding author: Jan Audun Rasmussen [ jan [dot] rasmussen [at] museummors [dot] dk ]

First record of tetrapod footprints from the Carboniferous Mesters Vig Formation in East Greenland.

Milàn, J., Klein, H., Voigt, S., & Stemmerik, L., 2016-08-11. First record of tetrapod footprints from the Carboniferous Mesters Vig Formation in East Greenland.
©2016 by Bulletin of the Geological Society of Denmark, Vol. 64, pp. 69–76. ISSN 2245-7070.
https://doi.org/10.37570/bgsd-2016-64-03

Abstract: A single slab with Late Palaeozoic tetrapod footprints from East Greenland has been housed at the Natural History Museum of Denmark for decades without scientific notice. The specimen comes from the Mesters Vig Formation of northern Scoresby Land in East Greenland and contains a monospecific assemblage of tetrapod footprints that we assign to Limnopus Marsh 1894. As there is no significant morphological difference from other records of this ichnogenus from North America, Europe and North Africa, the described tetrapod footprints can be referred to eryopoid temnospondyl trackmakers. Limnopus is well-known from Upper Carboniferous and Lower Permian continental deposits of palaeoequatorial Pangea. Identification of Limnopus tracks is in agreement with the supposed Late Carboniferous age of the Mesters Vig Formation and thereby also the first
evidence of Carboniferous tetrapods from Greenland.

Keywords: Carboniferous, vertebrate tracks, Limnopus, Temnospondyli, Traill Ø Group, Mesters Vig Formation.

Addresses:
Jesper Milàn [jesperm [at] oesm [dot] dk], Geomuseum Faxe, Østsjællands Museum, Østervej 2, DK-4640 Faxe, Denmark; also Natural History Museum of Denmark, Øster Voldgade 5–7, DK-1350 Copenhagen K., Denmark.
Hendrik Klein [hendrik [dot] klein [at] combyphone [dot] eu], Saurierwelt Paläontologisches Museum, Alte Richt 7, D-92318 Neumarkt, Germany.
Sebastian Voigt [s [dot] voigt [at] pfalzmuseum [dot] bv-pfalz [dot] de], Urweltmuseum GEOSKOP,
Burg Lichtenberg (Pfalz), Burgstraße 19, D-66871 Thallichtenberg, Germany.
Lars Stemmerik [lars [dot] stemmerik [at] snm [dot] ku [dot] dk], Natural History Museum of Denmark, Øster Voldgade 5–7, DK-1350 Copenhagen K., Denmark.

Corresponding author: Jesper Milàn

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Correlation of the Palaeogene successions on the North-East Greenland and Barents Sea margins.

Petersen, T.G, Hamann, N.E. & Stemmerik, L. 2016-11-16. Correlation of the Palaeogene successions on the North-East Greenland and Barents Sea margins.

©2016 by Bulletin of the Geological Society of Denmark, Vol. 64, pp. 77–96. ISSN 2245-7070. (www.2dgf/publikationer/bulletin).
https://doi.org/10.37570/bgsd-2016-64-04

Abstract: In this study we use seismic stratigraphy to link the Palaeogene succession of the North-East Green- land shelf with that of the more accurately dated Cenozoic succession on the partly conjugate Nor- wegian margin in the West Barents Sea. The margins show a comparable stacking of seismic facies and we propose that this symmetry reflects a genetic relationship between the conjugate plates. On both margins, the earliest deposition is constricted by highs inherited from Mesozoic rifting.

On the North-East Greenland shelf, the Danmarkshavn Ridge forms a barrier, whereas the footwall uplift along the west margin of Veslemøy High constrains the deposition in the West Barents Sea area. Pronounced progradational events shifted the depocentres of both margins towards the central axis of breakup during the more tectonically active breakup phase.

Deposition during the early drift stage is dominated by a relatively homogenous distribution of sediments across both margins and further basinward migration of the depocentres. Based on correlation of the seismic stratigraphic units, the Palaeogene succession of the North-East Greenland shelf is subdivided into pre-breakup deposits of early Paleocene age, syn-breakup deposits of latest Paleocene to early Eocene age and (early) drift deposits of late Eocene to Oligocene age.

Addresses:
Thomas Guldborg Petersen thomas [dot] guldborg [dot] petersen [at] hotmail [dot] com, Department of Geosciences and Natural Resources Management, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.

Niels Erik Hamann, DONG Energy, Nesa Allé 1, 2820 Gentofte, Denmark.

Lars Stemmerik lars [dot] stemmerik [at] snm [dot] ku [dot] dk, Natural History Museum, University of Copenhagen, Øster Voldgade 5–7, DK-1350 Copenhagen K, Denmark, and University Centre in Svalbard, P.O. Box 156, N-9171, Longyearbyen, Norway.

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Obliquorhynchia (gen. nov.): An asymmetric brachiopod from the middle Danian Faxe Formation, Denmark

Schrøder, A.E., Lauridsen, B.W. & Surlyk, F. 2016-11-23. Obliquorhynchia (gen. nov.): An asymmetric brachiopod from the middle Danian Faxe Formation, Denmark

©2016 by Bulletin of the Geological Society of Denmark, Vol. 64, pp. 97-109. ISSN 2245-7070. (www.2dgf/publikationer/bulletin).
https://doi.org/10.37570/bgsd-2016-64-05

Abstract: The diverse brachiopod fauna from the middle Danian cool-water coral mounds of the Faxe Formation, Denmark, includes the new genus Obliquorhynchia that exhibits an asymmetric folding of the frontal commissure, a rare feature in brachiopods. Two of the most abundant brachiopod species found in the Faxe Formation, ‘Rhynchonella’ flustracea and ‘Rhynchonella’ faxensis, are considered conspecific and are both referred to Obliquorhynchia. In the literature, the species name flustracea has been ascribed to von Schlotheim. However, the original species name proposed by von Schlotheim in his catalogue (1832, 65, no 62) was lustraceus. This remained a nomen nudum until von Buch (1834) published a description based on the material of von Schlotheim and changed the name to flustracea. The species is thus ascribed to von Buch. A lectotype for Obliquorhynchia flustracea (von Buch 1834) is designated and illustrated here.

Keywords:
Obliquorhynchia (gen. nov.), ‘Rhynchonella’ flustracea, ‘Rhynchonella’ faxensis, asymmetric brachiopods, middle Danian, Faxe Formation, Denmark.

Addresses:
Ane Elise Schrøder a [dot] schroder [dot] e [at] gmail [dot] com, Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark (also Østsjællands Museum, Højerup Bygade 38, DK-4660, Højerup, Denmark).

Bodil W. Lauridsen bwl [at] geus [dot] dk, Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.

Finn Surlyk finns [at] ign [dot] ku [dot] dk, University of Copenhagen, Department of Geosciences and Natural Resource Management, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.

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Tomagnostus brantevikensis n. sp. (Trilobita) from the middle Cambrian of Scania, Sweden

Weidner, T. & Nielsen, A.T. 2016-12-14. Tomagnostus brantevikensis n. sp. (Trilobita) from the middle Cambrian of Scania, Sweden.

©2016 by Bulletin of the Geological Society of Denmark, Vol. 64, pp. 111-116. ISSN 2245-7070. (www.2dgf/publikationer/bulletin).
https://doi.org/10.37570/bgsd-2016-64-06

Abstract:
Sparse material of an agnostid trilobite, previously referred to as Tomagnostus cf. corrugatus (Illing 1916), is recognized as a new species, T. brantevikensis n. sp. It occurs in the middle Cambrian (≈ Cambrian provisional Series 3) Triplagnostus gibbus and Acidusus atavus zones (Almbackenian regional Stage) in Scania, southernmost Sweden, but is very rare. The new species resembles T. corrugatus (Illing 1916) and T. perrugatus (Grönwall 1902), but the cephalon is characterized by a tapering glabella, creating an elongate subtriangular outline, and a deltoid depression. The pygidium has an evenly rounded border, is non-spinose, and has a long axis with a non-elongate node. Both shields
have a moderately wide border.

Keywords: Trilobites, agnostids, Tomagnostus, middle Cambrian, Scandinavia

Addresses:
Thomas Weidner to [dot] we [at] paradis [dot] dk, Ravnholtvej 23, Rårup, 7130 Juelsminde, Denmark.
Arne Thorshøj Nielsen arnet [at] ign [dot] ku [dot] dk, Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350 Kbh K, Denmark.

Corresponding author: Arne Thorshøj Nielsen

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