title: The Cenozoic palaeoenvironment of the Arctic Ocean.
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 approximately 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 (approximately 3.2 Myr ago) and East Antarctic ice (approximately 14 Myr ago). We find evidence for the first occurrence of ice-rafted debris in the middle Eocene epoch (approximately 45 Myr ago), some 35 Myr earlier than previously thought; fresh surface waters were present at approximately 49 Myr ago, before the onset of ice-rafted debris. Also, the temperatures of surface waters during the Palaeocene/Eocene thermal maximum (approximately 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.
authors.affiliation: Graduate School of Oceanography & Department of Ocean Engineering, University of Rhode Island, Narragansett, Rhode Island 02882, USA. kate.moran@gso.uri.edu
authors.forename: Kathryn
authors.initials: K
authors.lastname: Moran
authors.forename: Jan
authors.initials: J
authors.lastname: Backman
authors.forename: Henk
authors.initials: H
authors.lastname: Brinkhuis
authors.forename: Steven C
authors.initials: SC
authors.lastname: Clemens
authors.forename: Thomas
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authors.lastname: Cronin
authors.forename: Gerald R
authors.initials: GR
authors.lastname: Dickens
authors.forename: Frédérique
authors.initials: F
authors.lastname: Eynaud
authors.forename: Jérôme
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authors.lastname: Gattacceca
authors.forename: Martin
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authors.lastname: Jakobsson
authors.forename: Richard W
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authors.lastname: Jordan
authors.forename: Michael
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authors.lastname: Kaminski
authors.forename: John
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authors.lastname: King
authors.forename: Nalan
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authors.lastname: Koc
authors.forename: Alexey
authors.initials: A
authors.lastname: Krylov
authors.forename: Nahysa
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authors.lastname: Martinez
authors.forename: Jens
authors.initials: J
authors.lastname: Matthiessen
authors.forename: David
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authors.lastname: McInroy
authors.forename: Theodore C
authors.initials: TC
authors.lastname: Moore
authors.forename: Jonaotaro
authors.initials: J
authors.lastname: Onodera
authors.forename: Matthew
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authors.lastname: O'Regan
authors.forename: Heiko
authors.initials: H
authors.lastname: Pälike
authors.forename: Brice
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authors.lastname: Rea
authors.forename: Domenico
authors.initials: D
authors.lastname: Rio
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Sakamoto
authors.forename: David C
authors.initials: DC
authors.lastname: Smith
authors.forename: Ruediger
authors.initials: R
authors.lastname: Stein
authors.forename: Kristen
authors.initials: K
authors.lastname: St John
authors.forename: Itsuki
authors.initials: I
authors.lastname: Suto
authors.forename: Noritoshi
authors.initials: N
authors.lastname: Suzuki
authors.forename: Kozo
authors.initials: K
authors.lastname: Takahashi
authors.forename: Mahito
authors.initials: M
authors.lastname: Watanabe
authors.forename: Masanobu
authors.initials: M
authors.lastname: Yamamoto
authors.forename: John
authors.initials: J
authors.lastname: Farrell
authors.forename: Martin
authors.initials: M
authors.lastname: Frank
authors.forename: Peter
authors.initials: P
authors.lastname: Kubik
authors.forename: Wilfried
authors.initials: W
authors.lastname: Jokat
authors.forename: Yngve
authors.initials: Y
authors.lastname: Kristoffersen
mesh_terms: D000818:Animals; D001110:Arctic Regions; D002980:Climate; D029624:Ferns; D005580:Fossils; D019015:Geologic Sediments / Q000032:analysis* / Q000737:chemistry; D017752:Greenhouse Effect; D049690:History, Ancient; D046448:Ice Cover; D009792:Oceans and Seas; D012623:Seawater; D013696:Temperature; D013997:Time Factors