Chronological study of cosmic dust done on ice cores

[Mk]

http://www.ldeo.columbia.edu/news/2006/07_28_06b.htm

The study, which appears in the July 28 issue of the journal Science, involved researchers from the Lamont-Doherty Earth Observatory, a part of The Earth Institute, and the Alfred Wegener Institute for Polar and Marine Research (AWI) in Bremerhaven, Germany. The depth of the core they examined corresponded to the period between 6,800 and 29,000 years before the present day — a span that includes the height of the last glacial period, and the transition to warm conditions similar to today.

The scientists collected particulate matter from the EPICA (European Project for Ice Coring in Antarctica) ice core and measured the concentration of helium-3 (3He), a rare isotope that is plentiful in the sun's solar wind and is carried to Earth imbedded in cosmic dust particles measuring just a few thousandths of a millimeter in diameter. These dust particles carry their exotic helium load to the Earth’s surface where they are preserved in the snow and ice of the polar ice caps, among other places.

Because ice cores from the polar caps provide a high-resolution temporal record of the past, the researchers were able to measure fine variations in the rate of cosmic dust accumulation between glacial and interglacial periods as well as the helium isotope characteristics of these rare particles. They found that the accumulation of cosmic dust did not change appreciably as the Earth emerged from the last great Ice Age and entered the current warm period, a fact that is likely to bolster the use of cosmic dust measuring techniques in future climate studies.

In addition, this was the first study to examine both cosmic and terrestrial dust using the same helium-isotope technique. As a result, they also found that the composition of mineral dust particles carried by wind from the southern continents to Antarctica changed considerably as the Earth's climate changed.

"The terrestrial dust coming down on Antarctica during the Ice Age obviously is not the same as that during warm periods," said Gisela Winckler, a Doherty associate research scientist at Lamont-Doherty and lead author on the study. "This may be due to the mineral dust originating from different regional sources or to changes in the process responsible for producing the dust."

:/ Hmmm, interesting. (also, a German report http://www.awi-bremerhaven.de/AWI/Presse/PM/pm06-2.hj/060728Cosmic%20dust-e.html )

 

[Skyhunter]

http://www.ldeo.columbia.edu/news/2006/07_28_06b.htm

:/ Hmmm, interesting. (also, a German report http://www.awi-bremerhaven.de/AWI/Presse/PM/pm06-2.hj/060728Cosmic%20dust-e.html )

This could be useful in reducing the margin of error in past estimations of global temperature, especially the study of the terrestrial dust. Perhaps this study will elucidate the role, or non role, that cosmic dust plays in climate change.

 

[ravenprp]

The study of cosmic dust through ice cores is a fascinating and important area of research. By examining the concentration and characteristics of helium-3 in these tiny particles, scientists are able to gain insights into past climate conditions and changes on Earth.

The findings of this study, which spanned a period of 6,800 to 29,000 years, provide valuable information about the rate of cosmic dust accumulation during glacial and interglacial periods. The fact that the accumulation did not significantly change as the Earth transitioned from the last Ice Age to the current warm period is significant for future climate studies.

Furthermore, the study's use of the same helium-isotope technique to examine both cosmic and terrestrial dust allowed for the discovery of changes in the composition of mineral dust particles during different climate conditions. This adds to our understanding of the sources and processes behind dust production and transport.

Overall, this study highlights the importance of using ice cores as a high-resolution record of Earth's past, and the potential for cosmic dust measurements to provide valuable insights into our planet's history. It will be interesting to see how this research evolves and contributes to our understanding of the Earth's climate system.