14. Blue Ice in Antarctica
Antarctica is the best place in the world to find meteorites, and the search for Antarctic meteorites begins with the search for blue ice. This is an excellent meteorite hunting ground, not because more meteorites fall in Antarctica, but because meteorites are preserved and easy to find. Meteorites fall all over the world. Those that fall into the oceans are lost. Those that fall on land can be hard to see, one dark rock among other rocks or under leaves in a forest, and are lost quickly too, buried in soil and weathered. But in Antarctica, meteorites are easy to see — dark rocks on ice — and the harsh climate acts like a freezer to preserve meteorites, some for millions of years. A fallen meteorite in Antarctica is quickly covered by snow and buried in one of the great Antarctic glaciers. The glaciers slowly move toward the ocean, and their ice turns blue because all its air bubbles are squeezed out. Where the flow of the glaciers is impeded, for example, by the Antarctic Mountains shown in the slide, the blue ice may be thrust to the surface. Or the ice may just stop moving (become stagnant). Either way, the white surface ice evaporates in the dry winds of Antarctica, exposing blue ice and its meteorites.
It is hard to work and collect meteorites on blue ice. The surface of the ice is rippled from wind scouring, so it can look as beautiful as the sea surface in sunlight. However, the ice is solid, slippery as glass, and hard as rock. (Of course, you could fall into a crevasse, in which case, you might fall 500 or 600 feet to your death — a very real danger for each expedition.)
Once a blue ice field is identified, ANSMET team members on snowmobiles move slowly across it, looking at its whole expanse for rocks that might be meteorites. Snowmobiles allow the team to cover large icefields without the hazards of falling on the ice, and a snowmobile is more likely to straddle unseen crevasses than is a human foot.