Thew, Nigel, Kälin, Daniel, Cuenca-Bescós, Gloria et al. (7 more authors) (2024) The Hasli Formation of the Irchel Plateau – A key record for older Early Pleistocene interglacial sediments in northern Switzerland. Quaternary Science Reviews. 108550. ISSN 0277-3791
Abstract
In the Alpine region of Central Europe, terrestrial Early Pleistocene deposits with preserved faunal and botanical remains are rare. The predominantly gravelly Höhere Deckenschotter (HDS) deposits of northern Switzerland and adjoining south-western Germany are considered the oldest Quaternary sediments in the northern Alpine Foreland, linked with the first extensive Quaternary Alpine glaciations. This multidisciplinary study investigates the Hasli Formation (HF), a unique silty unit with well-preserved biological remains within an HDS sequence at the Irchel Plateau north of Zürich, providing new climatic and environmental data for these exceptional deposits, as well as crucial information about their age. Systematic mapping of the HF, in addition to the underlying and covering gravel units, has been coupled with sedimentary logging and biostratigraphic analysis at several sites. The HF is present over an area c.4 by up to 1.4 km, and where studied is 1.6–6.2 m thick. The sediments and biological material are indicative of overbank deposits accumulating within the damp floodplain of a large meandering river. The recovered small mammal remains are from eight arvicolid species or genera, including Mimomys pliocaenicus, M. reidi/tigliensis and Clethrionomys cf. kretzoii, which became extinct c.1.8 Ma, and Pliomys episcopalis/simplicior, which first appeared c.2 Ma ago. The over 75k identified molluscs, include c.72k coming from 89 terrestrial species and over 3k from 28 aquatic taxa. The molluscan faunas from all locations where the HF has been studied share important biostratigraphic marker species, and indicate analogous climatic and environmental conditions. The marker species include several that became extinct during the Early Pleistocene, of which Clausilia stranzendorfensis and Cochlostoma salomoni, present throughout the HF, are the most important as they disappeared c.1.8 Ma. Many marker species have modern or palaeo-distributions that lie far to the west, south and east of the Swiss Plateau, showing that the climate was much warmer than today, typical for the Tiglian warm stage. The alluvial floodplain was covered by rather dense, mature woodland. Amino acid (AA) analysis shows that molluscan remains from the HF are among the oldest of the Quaternary shell material studied from across the Swiss Plateau. Palaeomagnetic data shows a change from reversed to normal polarity within the upper part of the HF. When combined, the small mammal and molluscan remains, palaeomagnetic measurements, AA geochronology and sedimentary data, suggest an age of 2.1–1.8 Ma for the HF. Recently produced cosmogenic dates bracket the age of the HDS gravels beneath the HF to depositional periods between 2.6 and 0.9 Ma, with the youngest ages being in disagreement with our findings. The abundance and diversity of the molluscs from the Irchel Plateau, with several rare extinct species, together with a notable small mammal assemblage, make this a key palaeontological site and an important reference point for European Quaternary biostratigraphy.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2024 The Authors. Published by Elsevier Ltd. Funding Information: We would like to thank Jos\u00E9 Ignacio Canudo, Florian Kober and Ren\u00E9 L\u00F6pfe for help with field work and Thomas Gubler for surveying the HDS outcrops. We are grateful to Old\u0159ich Fejfar for assistance identifying the small mammals, Pierre-Olivier Mojon for identifying the Chara, Georges Haldimann for photographing the molluscs, Sheila Taylor and Sam Presslee for AA technical assistance, plus Claudia Frei and Ren\u00E9 L\u00F6pfe for graphical support. We are indebted to Florian Kober and Angela Landgraf for their valuable input for the section concerning the cosmogenic ages. The study was funded by the Swiss National Cooperative for the Disposal of Radioactive Waste (Nagra), with some AA analyses supported through the EQuaTe Project that is funded by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No. 865222). Special thanks go to H. Beereuter and the municipal authorities at Buch am Irchel, Berg am Irchel, Freienstein-Teufen and D\u00E4ttlikon for supporting this study. The manuscript greatly benefited from very helpful and detailed review comments by Oleksandr Kovalchuk, Nicole Limondin-Lozouet and Lutz Maul. Funding Information: We would like to thank Jos\u00E9 Ignacio Canudo, Florian Kober and Ren\u00E9 Loepfe for help with field work and Thomas Gubler for surveying the HDS outcrops. We are grateful to Old\u0159ich Fejfar for assistance identifying the small mammals, Pierre-Olivier Mojon for identifying the Chara, Georges Haldimann for photographing the molluscs, Sheila Taylor and Sam Presslee for AA technical assistance, plus Claudia Frei and Ren\u00E9 Loepfe for graphical support. We are indebted to Florian Kober and Angela Landgraf for their valuable input for the section concerning the cosmogenic ages. The study was funded by the Swiss National Cooperative for the Disposal of Radioactive Waste (Nagra), with some AA analyses supported through the EQuaTe Project that is funded by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No. 865222 ). Special thanks go to H. Beereuter and the municipal authorities at Buch am Irchel, Berg am Irchel, Freienstein-Teufen and D\u00E4ttlikon for supporting this study. The manuscript greatly benefited from very helpful and detailed review comments by Oleksandr Kovalchuk, Nicole Limondin-Lozouet and Lutz Maul. |
Keywords: | Alluvial sediments,Amino acid geochronology,Biostratigraphy,Central Europe,Interglacial palaeoclimate,Magnetostratigraphy,Molluscs,Older Early Pleistocene (Gelasian),Palaeoenvironments,Small mammals |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Chemistry (York) |
Funding Information: | Funder Grant number EUROPEAN COMMISSION 865222 |
Depositing User: | Pure (York) |
Date Deposited: | 08 May 2024 11:50 |
Last Modified: | 16 Oct 2024 19:56 |
Published Version: | https://doi.org/10.1016/j.quascirev.2024.108550 |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.1016/j.quascirev.2024.108550 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:212353 |
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