ANSMET

ANSMET (ANtarctic Search for METeorites) is a program funded by the Office of Polar Programs of the National Science Foundation that looks for meteorites in the Transantarctic Mountains. This geographical area serves as a collection point for meteorites that have originally fallen on the extensive high-altitude ice fields throughout Antarctica. Such meteorites are quickly covered by subsequent snowfall and begin a centuries-long journey traveling "downhill" across the Antarctic continent while embedded in a vast sheet of flowing ice. Portions of such flowing ice can be halted by natural barriers such as the Transantarctic Mountains. Subsequent wind erosion of the motionless ice brings trapped meteorites back to the surface once more where they may be collected. This process concentrates meteorites in a few specific areas to much higher concentrations than they are normally found everywhere else. The contrast of the dark meteorites against the white snow, and lack of terrestrial rocks on the ice, makes such meteorites relatively easy to find. However, the vast majority of such ice-embedded meteorites eventually slide undiscovered into the ocean.

Importance

The ANSMET program, together with parallel Antarctic collection programs run by Japan, China, and other nations, is a major source of the extraterrestrial material that is available for scientific investigation. All of the material collected by ANSMET is curated for the purpose of research and public education, in contrast to meteorites collected privately, the bulk of which are frequently sold to collectors and lost to science. ANSMET has provided many of the known lunar and martian meteorites such as ALH84001.

Method

The search for the meteorites is done visually. A team of six, lives for 5–7 weeks on the ice field. Using snowmobiles spaced 30 m apart they scan the blue ice for meteorites. Once a specimen has been located its position is found using GPS and it is given an identification number. It is then placed in a sterile Teflon bag. The teams make sure that the specimen remains frozen throughout its journey back to the [http://www-curator.jsc.nasa.gov/antmet/index.cfm Antarctic Meteorite Curation Facility] at the Johnson Space Center in Houston, Texas. Since 1976, ANSMET has returned over 10,000 meteorites. Ultimately, all samples collected by ANSMET are transferred to the Smithsonian Institution for permanent storage and curation.

The 2004-2005 ANSMET expedition consisted of 12 members and collectively they returned 1,230 meteorites. These included over 130 kg of pallasite meteorites, one of which is the largest yet found in Antarctica at over 30 kg.

Further reading

William A. Cassidy, "Meteorites, Ice and Antarctica", Cambridge University Press (2003), ISBN 0521258723

External links

* [http://geology.cwru.edu/~ansmet/ ANSMET]
* [http://www.webexpeditions.net/ansmet/ ANSMET Antarctic Meteorite Recovery Expedition 2001]
* cite web
title=Antarctica is a Hot Spot for UA Scientists Hunting Meteorites | work=UA News
url=http://uanews.org/cgi-bin/WebObjects/UANews.woa/wa/MainStoryDetails?ArticleID=11975
accessmonthday=November 16
accessyear=2005
* [http://geology.cwru.edu:16080/~amlamp/intro/ Antarctic Meteorite Location and Mapping Project (AMLAMP)]
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