Skip to Main content Skip to Navigation
Journal articles

A climatic control on the accretion of meteoric and super-chondritic iridium–platinum to the Antarctic ice cap

Abstract : Meteoric smoke particles (MSPs) form through the vaporization of meteoroids and the subsequent re-condensation of metallic species in the mesosphere. Recently, iridium and platinum enrichments have been identified in Greenland ice layers and attributed to the fallout of MSPs supplying polar latitudes with cosmic matter during the Holocene. However, the MSP fallout to Antarctica during the Earth's climatic history remains essentially unknown. We have determined iridium and platinum in deep Antarctic ice from Dome C and Vostok dated back to 240 kyrs BP. We find high super-chondritic fluxes during warm periods and low meteoric accretion during glacial times, a pattern that is opposite to any known climatic variation in dust fallout to polar regions. The proposed explanation of this accretion regime is a weaker polar vortex during warm periods, allowing peripheral air masses enriched in volcanic iridium and platinum to penetrate inland to Antarctica. The MSP signal emerges only during cold phases and is four times lower than in the Greenland ice cap where more snow accumulates. This suggests that wet deposition is an important route of cosmic material to the Earth's surface.
Complete list of metadatas

https://hal-insu.archives-ouvertes.fr/insu-00375474
Contributor : Aurore Gayraud <>
Submitted on : Wednesday, April 15, 2009 - 11:00:18 AM
Last modification on : Friday, September 25, 2020 - 9:16:02 AM

Identifiers

Collections

Citation

Paolo Gabrielli, John M.C. Plane, Claude F. Boutron, Sungmin Hong, Giulio Cozzi, et al.. A climatic control on the accretion of meteoric and super-chondritic iridium–platinum to the Antarctic ice cap. Earth and Planetary Science Letters, Elsevier, 2006, 250 (3-4), pp.459 à 469. ⟨10.1016/j.epsl.2006.08.015⟩. ⟨insu-00375474⟩

Share

Metrics

Record views

271