Magnetization of polar ice: a measurement of terrestrial dust and extraterrestrial fallout

QUATERNARY SCIENCE REVIEWS

卷:33

Article

Lanci, L.¹  Delmonte, B.²  Kent, D. V.^3,4  Maggi, V.²  Biscaye, P. E.⁴  Petit, J. -R.⁵ 

[1] Univ Urbino, Dept DISTEVA, I-61029 Urbino, Italy

[2] Univ Milano Bicocca, Dipartimento Sci Ambientali, Milan, Italy

[3] Rutgers State Univ, Dept Earth & Planetary Sci, Piscataway, NJ USA

[4] Lamont Doherty Earth Observ, Palisades, NY USA

[5] Lab Glaciol & Geophys Environm, F-38402 St Martin Dheres, France

关键词: Rock-magnetism;    Ice cores;    Atmospheric dust;    Meteoric smoke;    Micrometeorites;   

DOI  :  10.1016/j.quascirev.2011.11.023

来源: Elsevier

【 摘 要 】

Laboratory-induced remanent magnetization of polar ice constitutes a measurement of the magnetization carried by the ferromagnetic dust particles in the ice. This non-destructive technique provides a novel kind of information on the dust deposited on the surface of polar ice sheets. Measurements made on ice samples from Greenland (North GRIP ice core) and Antarctica (Vostok and EPICA-Dome C ice cores) allowed the recognition of a fraction of magnetic minerals in ice whose concentration and magnetic properties are directly related to that of insoluble dust. The source of this fraction of magnetic minerals thus appears closely related to terrestrial dust transport and deposition and its magnetic properties are informative of the dust provenance areas. The rock-magnetic properties of the dust may reflect distinct, changes of dust source areas from glacial to interglacial periods in agreement with and adding further information to the isotopic (Sr-87/Sr-86 and Nd-143/Nd-144) analyses. A second magnetic fraction consists of particles of nanometric size, which are superparamagnetic at freezer temperature and whose concentration is independent of the mass of aerosol dust found in the ice. The source of these nanometric-sized magnetic particles is ascribed to fallout of meteoric smoke and their concentration in ice was found to be compatible with the extraterrestrial fallout inferred from Ir concentrations. The diameter of the smoke particles as inferred from magnetic measurements is in the range of about 7-20 nm. (C) 2011 Elsevier Ltd. All rights reserved.

【 授权许可】

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