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AGU: Geophysical Research Letters

 

Keywords

  • Antarctica
  • ice core
  • micrometeorites

Index Terms

  • Cryosphere: Ice cores
  • Interplanetary Physics: Interplanetary dust
  • Atmospheric Processes: Paleoclimatology
  • Geographic Location: Antarctica

Abstract

GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L15502, 5 PP., 2007
doi:10.1029/2007GL030801

First discovery of meteoritic events in deep Antarctic (EPICA-Dome C) ice cores

Biancamaria Narcisi

Centro Ricerche Casaccia, Ente per le Nuove Technologie, l'Energia e l'Ambiente, Rome, Italy

Jean Robert Petit

Laboratoire de Glaciologie et Géophysique de l'Environnement, Centre National de la Recherche Scientifique, Saint Martin d'Hères, France

Cécile Engrand

Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse, Centre National de la Recherche Scientifique & Université Paris Sud, Orsay, France

Two distinct dust layers in the EPICA-Dome C ice core (75°06′S, 123°21′E, East Antarctic Plateau) have been shown to relate to individual meteoritic events. Particles forming these layers, investigated by electron microprobe, show peculiar textural, mineralogical and geochemical features and closely resemble extraterrestrial debris in deep-sea sediments and polar caps. Preliminary estimates of cosmic debris input at the studied layers, obtained from Coulter Counter measurements, are 4–5 orders of magnitude greater than the yearly micrometeorite flux in East Antarctic snow and ice. The cosmic events are accurately dated through glaciological models at 434 ± 6 and 481 ± 6 ka, respectively and are located in the core climatic stratigraphy near the “Mid-Brunhes Event”. This is the first report of well-dated cosmic horizons in deep Antarctic ice cores. It significantly improves the extraterrestrial record of Antarctica and opens new correlation perspectives between long climatic records of the South polar region.

Received 25 May 2007; accepted 17 July 2007; published 11 August 2007.

Citation: Narcisi, B., J. R. Petit, and C. Engrand (2007), First discovery of meteoritic events in deep Antarctic (EPICA-Dome C) ice cores, Geophys. Res. Lett., 34, L15502, doi:10.1029/2007GL030801.

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