The Cenozoic palaeoenvironment of the Arctic Ocean.
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.
Moran
Kathryn
K
Graduate School of Oceanography & Department of Ocean Engineering, University of Rhode Island, Narragansett, Rhode Island 02882, USA. kate.moran@gso.uri.edu
Backman
Jan
J
Brinkhuis
Henk
H
Clemens
Steven C
SC
Cronin
Thomas
T
Dickens
Gerald R
GR
Eynaud
Frédérique
F
Gattacceca
Jérôme
J
Jakobsson
Martin
M
Jordan
Richard W
RW
Kaminski
Michael
M
King
John
J
Koc
Nalan
N
Krylov
Alexey
A
Martinez
Nahysa
N
Matthiessen
Jens
J
McInroy
David
D
Moore
Theodore C
TC
Onodera
Jonaotaro
J
O'Regan
Matthew
M
Pälike
Heiko
H
Rea
Brice
B
Rio
Domenico
D
Sakamoto
Tatsuhiko
T
Smith
David C
DC
Stein
Ruediger
R
St John
Kristen
K
Suto
Itsuki
I
Suzuki
Noritoshi
N
Takahashi
Kozo
K
Watanabe
Mahito
M
Yamamoto
Masanobu
M
Farrell
John
J
Frank
Martin
M
Kubik
Peter
P
Jokat
Wilfried
W
Kristoffersen
Yngve
Y
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