Comment on egusphere-2023-36

Abstract

Abstract. There is a temporal correlation between the peak activity of the North Atlantic Igneous Province (NAIP) and the Paleocene–Eocene Thermal Maximum (PETM), suggesting that the NAIP may have initiated and/or prolonged this extreme warming event. However, corroborating a causal relationship is hampered by a scarcity of expanded sedimentary records that contain both climatic and volcanic proxies. One locality hosting such a record is Fur Island in Denmark, where an expanded pre- to post-PETM succession containing hundreds of NAIP ash layers is exceptionally well preserved. We compiled a range of environmental proxies, including mercury (Hg) anomalies, paleotemperature proxies, and lithium (Li) and osmium (Os) isotopes, to trace NAIP activity, hydrological changes, weathering, and seawater connectivity across this interval. Volcanic proxies suggest that NAIP activity was elevated before the PETM and appears to have peaked during the body of the δ13C excursion, but decreased considerably during the PETM recovery. This suggests that the acme in NAIP activity, dominated by flood basalt volcanism and thermogenic degassing from contact metamorphism, was likely confined to just ~200 kyr (ca. 56.0–55.8 Ma). The hundreds of thick basaltic ashes in the post-PETM strata likely represent a change from effusive to explosive activity, rather than an increase in NAIP activity. Detrital δ7Li values and clay abundances suggest that volcanic ash production increased basaltic reactive surface area, likely enhancing silicate weathering and atmospheric carbon sequestration in the early Eocene. Signals in lipid biomarkers and Os isotopes, traditionally used to trace paleotemperature and weathering changes, are used here to track seaway connectivity. These proxies indicate that the North Sea was rapidly cut off from the North Atlantic in under 12 kyr during the PETM recovery due to NAIP thermal uplift. Our findings reinforce the hypothesis that the emplacement of the NAIP had a profound and complex impact on Paleocene–Eocene climate, both directly through volcanic and thermogenic degassing, and indirectly by driving regional uplift and changing seaway connectivity.

Authors 15

1. Morgan T. Jones corresponding

   University of Oslo

   Affiliation as printed

   Centre for Earth Evolution and Dynamics (CEED), University of Oslo, PO Box 1028 Blindern, 0315, Oslo, Norway

2. Ella W. Stokke

   University of Oslo

   Affiliation as printed

   Centre for Earth Evolution and Dynamics (CEED), University of Oslo, PO Box 1028 Blindern, 0315, Oslo, Norway

3. Alan D. Rooney

   Yale University

   Affiliation as printed

   Department of Earth & Planetary Sciences, Yale University, PO Box 208109, New Haven CT 06520-8109, USA

4. Joost Frieling

   University of Oxford

   Affiliation as printed

   Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, U.K

5. Philip A.E. Pogge von Strandmann

   Johannes Gutenberg University Mainz · University College London · Birkbeck, University of London

   Affiliation as printed

   London Geochemistry and Isotope Centre (LOGIC), Institute of Earth and Planetary Sciences , University College London and Birkbeck, University of London, Gower Street, London WC1E 6BT, UK

   Mainz Isotope and Geochemistry Centre (MIGHTY), Institute of Geosciences, Johannes Gutenberg University, 55122 Mainz, Germany

6. D.J. Wilson

   University College London · Birkbeck, University of London

   Affiliation as printed

   London Geochemistry and Isotope Centre (LOGIC), Institute of Earth and Planetary Sciences , University College London and Birkbeck, University of London, Gower Street, London WC1E 6BT, UK

7. Henrik Hovland Svensen

   University of Oslo

   Affiliation as printed

   Centre for Earth Evolution and Dynamics (CEED), University of Oslo, PO Box 1028 Blindern, 0315, Oslo, Norway

8. Sverre Planke

   University of Oslo · Volcanic Basin Petroleum Research (Norway)

   Affiliation as printed

   Centre for Earth Evolution and Dynamics (CEED), University of Oslo, PO Box 1028 Blindern, 0315, Oslo, Norway

   Volcanic Basin Petroleum Research (VBPR AS), Høienhald, Blindernveien 5, N-0361 Oslo, Norway

9. Thierry Adatte

   University of Lausanne

   Affiliation as printed

   Institute of Earth Sciences, University of Lausanne, 1015 Lausanne, Switzerland

10. Nicolas Rudolph Thibault

    University of Copenhagen

    Affiliation as printed

    Department of Geosciences and Natural Resource Management, University of Copenhagen, 1350 Copenhagen K, Denmark

11. Madeleine L. Vickers

    University of Oslo

    Affiliation as printed

    Centre for Earth Evolution and Dynamics (CEED), University of Oslo, PO Box 1028 Blindern, 0315, Oslo, Norway

12. Tamsin A. Mather

    University of Oxford

    Affiliation as printed

    Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, U.K

13. Christian Tegner

    Aarhus University

    Affiliation as printed

    Department of Geoscience, Aarhus University, Høegh-Guldbergs Gade 2, 8000 Aarhus C, Denmark

14. Valentin Zuchuat Aachen Palaeontology and Geological Institute

    RWTH Aachen University

    Affiliation as printed

    Palaeontology and Geological Institute, Aachen University, Bergbaugebäude 1140, Wüllnerstraße 2, Aachen, Germany

15. Bo Pagh Schultz

    Museum Salling

    Affiliation as printed

    Museum Salling – Fur Museum, 7884 Fur, Denmark