| Trapping Gases in the Ice |
|
|
|
|
|
|
|
|
|
|
|
| q | Air moves freely through snow |
|||||||||
| and ice in the upper 15 m of an |
||||||||||
| ice sheet. |
||||||||||
| q | Flow is increasingly restricted |
|||||||||
| below this level. |
||||||||||
| q | Bubbles of old air are |
|||||||||
| eventually sealed off completely |
||||||||||
| in ice 50 to 100 m below the |
||||||||||
| surface. |
||||||||||
