PALEOCEANOGRAPHY. A warm and poorly ventilated deep Arctic Mediterranean during the last glacial period.
Changes in the formation of dense water in the Arctic Ocean and Nordic Seas [the "Arctic Mediterranean" (AM)] probably contributed to the altered climate of the last glacial period. We examined past changes in AM circulation by reconstructing radiocarbon ventilation ages of the deep Nordic Seas over the past 30,000 years. Our results show that the glacial deep AM was extremely poorly ventilated (ventilation ages of up to 10,000 years). Subsequent episodic overflow of aged water into the mid-depth North Atlantic occurred during deglaciation. Proxy data also suggest that the deep glacial AM was ~2° to 3°C warmer than modern temperatures; deglacial mixing of the deep AM with the upper ocean thus potentially contributed to the melting of sea ice, icebergs, and terminal ice-sheet margins.
Woods Hole Oceanographic Institution (WHOI), Woods Hole, MA 02543, USA. Department of Geography, University College London, London WC1E 6BT, UK.
D J R
DJ
Thornalley
Academy of Sciences, Humanities and Literature, Mainz, and GEOMAR Helmholtz Centre for Ocean Research, 24148 Kiel, Germany.
H A
HA
Bauch
Woods Hole Oceanographic Institution (WHOI), Woods Hole, MA 02543, USA.
G
G
Gebbie
Woods Hole Oceanographic Institution (WHOI), Woods Hole, MA 02543, USA.
W
W
Guo
Eidgenössische Technische Hochschule Zürich, 8093 Zurich, Switzerland.
M
M
Ziegler
Eidgenössische Technische Hochschule Zürich, 8093 Zurich, Switzerland.
S M
SM
Bernasconi
School of Earth and Ocean Sciences, Cardiff University, Cardiff CF10 3XQ, UK.
S
S
Barker
Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK.
L C
LC
Skinner
Research School of Earth Sciences, Australian National University, Acton, ACT 0200, Australia.
J
J
Yu