Image:GISP2D1837 crop.jpg
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Cropped from en:Image:GISP2D1837.jpg. Cropped and uploaded by User:HereToHelp; original uploaded by en:User:Dragons flight; made by USGS. The documentation is reproduced here:
[edit] Description
This photograph shows a section of the GISP2 ice core from 1837-1838 meters in which annual layers are clearly visible. The appearance of layers results from differences in the size of snow crystals deposited in winter versus summer and resulting variations in the abundance and size of air bubbles trapped in the ice. Counting such layers has been used (in combination with other techniques) to reliably determine the age of the ice. This ice was formed ~16250 years ago during the final stages of the last ice age and approximately 38 years are represented here. By analyzing the ice and the gases trapped within, scientists are able learn about past climate conditions.
[edit] Copyright
This image was produced at the en:National Ice Core Laboratory by employees of the USGS with funding from the NSF, and consequently is in the public domain.
It was kindly provided by Eric Cravens, Assistant Curator, National Ice Core Laboratory.
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This image is in the public domain because it contains materials that originally came from the United States Geological Survey, an agency of the United States Department of Interior. For more information, see the official USGS copyright policy |
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