Here is a Glaciological TED talk I discovered the other day. Lee Hotz, a science columnist, talks about ice-core drilling in Antarctica. Ice cores are often referred to as time machines, because as snow falls layer upon layer and gets compressed as ice it preserves a frozen signature of the distance past. For example, the air pockets in snow contain information on atmospheric composition now locked within the ice column. In fact one of the sad consequences of the disappearance of many glaciers, especially those in equatorial regions, such as on Mount Kilimanjaro, is that these valuable time capsules are literally being washed away.
For those that are further interested, Richard Alley, a famous Glaciologist, has written a popular level book on ice core drilling called the The Two-Mile Time Machine: Ice Cores, Abrupt Climate Change, and Our Future: