1. Graduate School of Oceanography & Department of Ocean Engineering, University of Rhode Island, Narragansett, Rhode Island 02882, USA
2. Department of Geology & Geochemistry, Stockholm University, Stockholm SE-106 91, Sweden
3. Laboratory of Palaeobotany & Palynology, Department of Biology, Utrecht University, 3584 DC Utrecht, The Netherlands
4. Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA
5. US Geological Survey, Reston, Virginia 20192, USA
6. Department of Earth Science, Rice University, Houston, Texas 77251, USA
7. Département de Géologie et Océanographie, Université Bordeaux, 33405 Talence, France
8. Department of Geophysics, CEREGE (CNRS), 13545 Aix-en-Provence, France
9. Department of Earth & Environmental Sciences, Yamagata University, Yamagata 990-8560, Japan
10. Department of Earth Sciences, University College London, London WC1E 6BT, UK
11. Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island 02882, USA
12. Norwegian Polar Institute, Polar Environmental Center, 9296 Tromsø, Norway
13. Department of Lithology & Geochemistry, VNIIOkeangeologia, St Petersburg 190121, Russia
14. Earth Sciences, Boston University, Boston, Massachusetts 02215, USA
15. Alfred Wegener Institute Foundation for Polar and Marine Research, D-27515 Bremerhaven, Germany
16. British Geological Survey, Murchison House, Edinburgh EH9 3LA, UK
17. Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA
18. Department of Earth and Planetary Sciences, Kyushu University, Fukuoka 812-8581, Japan
19. National Oceanography Centre, University of Southampton, Southampton SO14 3ZH, UK
20. Department of Geography & Environment, University of Aberdeen, Aberdeen AB24 3UF, UK
21. Department of Geology, Paleontology & Geophysics, University of Padova, Padova 35137, Italy
22. Institute for Research on Earth Evolution (IFREE), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka 237-0061, Japan
23. Department of Geology & Environmental Science, James Madison University, Harrisonburg, Virginia 22807, USA
24. Department of Earth & Planetary Sciences, Nagoya University, Chikusa, Nagoya 464-8602, Japan
25. Institute of Geology & Paleontology, Tohoku University, Sendai City 980-8578, Japan
26. Institute of Geoscience, Geological Survey of Japan, Ibaraki 305-8567, Japan
27. Graduate School of Environmental Earth Science, Hokkaido University, Sapporo 060-0810, Japan
28. Leibniz-Institute of Marine Sciences, IFM-GEOMAR, 24148 Kiel, Germany
29. Paul Scherrer Institute, ETH-Hönggerberg, CH-8093 Zurich, Switzerland
30. Department of Earth Science, University of Bergen, Allegaten 41, N-5007 Bergen, Norway

Correspondence to: Kathryn Moran¹ Correspondence and requests for materials should be addressed to K.M. (Email: kate.moran@gso.uri.edu).

Abstract

The history of the Arctic Ocean during the Cenozoic era (0–65 million years ago) is largely unknown from direct evidence. Here we present a Cenozoic palaeoceanographic record constructed from >400 m of sediment core from a recent drilling expedition to the Lomonosov ridge in the Arctic Ocean. Our record shows a palaeoenvironmental transition from a warm 'greenhouse' world, during the late Palaeocene and early Eocene epochs, to a colder 'icehouse' world influenced by sea ice and icebergs from the middle Eocene epoch to the present. For the most recent 14 Myr, we find sedimentation rates of 1–2 cm per thousand years, in stark contrast to the substantially lower rates proposed in earlier studies; this record of the Neogene reveals cooling of the Arctic that was synchronous with the expansion of Greenland ice (3.2 Myr ago) and East Antarctic ice (14 Myr ago). We find evidence for the first occurrence of ice-rafted debris in the middle Eocene epoch (45 Myr ago), some 35 Myr earlier than previously thought; fresh surface waters were present at 49 Myr ago, before the onset of ice-rafted debris. Also, the temperatures of surface waters during the Palaeocene/Eocene thermal maximum (55 Myr ago) appear to have been substantially warmer than previously estimated. The revised timing of the earliest Arctic cooling events coincides with those from Antarctica, supporting arguments for bipolar symmetry in climate change.

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