Is ice-rafted sediment in a North Pole marine record evidence for perennial sea-ice cover?

被引:14
作者
Tremblay, L. B. [1 ,4 ]
Schmidt, G. A. [2 ]
Pfirman, S. [3 ]
Newton, R. [4 ]
DeRepentigny, P. [1 ]
机构
[1] McGill Univ, Dept Atmospher & Ocean Sci, Montreal, PQ H3A 0B9, Canada
[2] NASA, Goddard Inst Space Studies, New York, NY 10025 USA
[3] Columbia Univ Barnard Coll, New York, NY 10027 USA
[4] Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA
来源
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES | 2015年 / 373卷 / 2052期
基金
加拿大自然科学与工程研究理事会; 美国国家科学基金会;
关键词
Arctic; sea ice; palaeoclimate; WESTERN ARCTIC-OCEAN; MENDELEEV RIDGE; HISTORY; CLIMATE; VARIABILITY; GREENLAND; MODEL; DRIFT; ARCHIPELAGO; CIRCULATION;
D O I
10.1098/rsta.2014.0168
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Ice-rafted sediments of Eurasian and North American origin are found consistently in the upper part (13 Ma BP to present) of the Arctic Coring Expedition (ACEX) ocean core from the Lomonosov Ridge, near the North Pole (approximate to 88 degrees N). Based on modern sea-ice drift trajectories and speeds, this has been taken as evidence of the presence of a perennial sea-ice cover in the Arctic Ocean from the middle Miocene onwards (Krylov et al. 2008 Paleoceanography 23, PA1S06. (doi:10.1029/2007PA001497); Darby 2008 Paleoceanography 23, PA1S07. (doi: 10.1029/2007PA001479)). However, other high latitude land and marine records indicate a long-term trend towards cooling broken by periods of extensive warming suggestive of a seasonally ice-free Arctic between the Miocene and the present (Polyak et al. 2010 Quaternary Science Reviews 29, 1757-1778. (doi: 10.1016/j.quascirev.2010.02.010)). We use a coupled sea-ice slab-ocean model including sediment transport tracers to map the spatial distribution of ice-rafted deposits in the Arctic Ocean. We use 6 hourly wind forcing and surface heat fluxes for two different climates: one with a perennial sea-ice cover similar to that of the present day and one with seasonally ice-free conditions, similar to that simulated in future projections. Model results confirm that in the present-day climate, sea ice takes more than 1 year to transport sediment from all its peripheral seas to the North Pole. However, in a warmer climate, sea-ice speeds are significantly faster (for the same wind forcing) and can deposit sediments of Laptev, East Siberian and perhaps also Beaufort Sea origin at the North Pole. This is primarily because of the fact that sea-ice interactions are much weaker with a thinner ice cover and there is less resistance to drift. We conclude that the presence of ice-rafted sediment of Eurasian and North American origin at the North Pole does not imply a perennial sea-ice cover in the Arctic Ocean, reconciling the ACEX ocean core data with other land and marine records.
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页数:12
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