Skip to main content
search
0

A Baltoscandian view of the biotic radiations related to the Darriwilian shift into the Ordovician icehouse

Geoscientists documented the Great Ordovician Biodiversification Event (GOBE) within various clades. This has led to a discussion of mechanisms controlling the ecosystem changes that pushed a distinct Darriwilian peak in global biodiversity. A complex interplay of factors such as the highest dispersal of continental plates and the largest tropical shelf areas during the Palaeozoic, a very intense volcanic activity, extra-terrestrial dust input related to an asteroid breakup (L-chondrite parent body, LCPB), increased faunal interactions and competition in complex ecosystems presumably played a major role. However, scientists widely agree that global climate cooling was probably the major trigger for the GOBE.

Our high resolution δ18O and δ 13C study together with a bed-by-bed appraisal of conodont species richness in the Hällekis quarry at Kinnekulle (southern Sweden), displays a rising curve up through the Lenodus antivariabilis conodont zone (CZ). This is followed by a peak in the lowermost Lenodus variabilis CZ a plateau and a two-phased drop in richness in the upper variabilis CZ. Our δ18O record supports the results of a microfacies-derived sea level curve, indicating that the studied interval was mainly deposited during colder climates. The richness plateau and extinction pulse occurred when sea level was at its lowest. The suggestion that the LCPB disruption caused an enhanced flux of micro-meteorites to Earth around 467 Ma, triggering climate cooling and intensifying the GOBE, is heavily debated since the inferred LCPB level occurs within an overall period of cooling.

Details

Author
Oliver* Lehnert1, Christian M.Ø. Rasmussen2, Svend Stouge3, Anders Lindskog4, Michael M. Joachimski5, Zhutong Zhang6, Rongchang Wu7, Guanzhou Yan8, Fangyi Gong7, Mikael Calner4, Peep Männik9
Institutionen
1GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 5, D-91054Erlangen, Germany;State Key Laboratory of Palaeobiology and Stratigraphy & Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing, China; 2Globe Institute, University of Copenhagen, Øster Voldgade 5–7, DK-1350 Copenhagen K, Denmark;Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark; 3deceased 12th April 2025, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK-1350 Copenhagen K, Denmark; 4Department of Geology, Lund University, Sölvegatan 12 223 62 Lund, Sweden; 5GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 5, D-91054Erlangen, Germany; 6State Key Laboratory of Lithospheric and Environmental Coevolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;College of Earth and Planetary Science, University of Chinese Academy of Sciences, Beijing 100049, China; 7State Key Laboratory of Palaeobiology and Stratigraphy & Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing, China; 8State Key Laboratory of Palaeobiology and Stratigraphy & Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing, China;Department of Geology, Lund University, Sölvegatan 12 223 62 Lund, Sweden; 9Tallinn University of Technology, Institute of Geology, Ehitajate tee 5, 19086 Tallinn, Estonia
Veranstaltung
Geo4Göttingen 2025
Datum
2025
DOI
10.48380/dbrx-7s97

zurück zur Übersicht