All About Ice
With ice covering 98% of Antarctica, there’s an amazing variety. Here’s the low-down on all this ice, ice baby! (I couldn’t resist…)
Clear Ice: Clear ice is made by snow falling on glaciers. The snow becomes compressed, eliminating the air bubbles. Without bubbles, the light is able to penetrate the ice, making it transparent. The clearer the ice is, the older it is since the impurities have been squeezed out over time. A truly clear piece of ice can be 10,000 years old.
Here’s one of the expedition staff, Doug, holding a phenomenally clear piece of ice we found floating in the water. (We later put the ice to good use as a “luge” up in the bar.)
Blue Ice: Why is ice blue? Here’s what Wikipedia says (which, to be honest, I don’t quite understand):
“In ice, the absorption of light at the red end of the spectrum is 6 times greater than at the blue end. Thus the deeper light energy travels, the more photons from the red end of the spectrum it loses along the way. Two meters into the glacier, most of the reds are dead. A lack of reflected red wavelengths produces the color blue in the human eye.”
What I do understand is how beautiful the intensely blue, glowing ice is…
Glaciers are ice, water, and air and cover most of Antarctica. Three-fourths of the world’s water is glacial. Glaciers move about 30 centimeters a day and eventually melt into the ocean.
There are two types of glaciers: continental and valley. Continental glaciers, which are extremely thick, are known as ice caps. The biggest glacier in the world is 210,000 feet thick. Valley glaciers fill the valleys between mountains.
Once a glacier reaches the ocean, it splitters apart and forms an iceberg. The largest icebergs are more than 1 million tons.
But it’s hard to tell how big icebergs really are because most of the berg is under water, with only the top sticking up. There was an iceberg the size of Belgium. That’s huge!
Icebergs are incredibly unstable and can flip over at any time. Here I am standing on an iceberg (which was supposedly “grounded” and stable):
Much of Antarctica is surrounded by ice shelves, which are the result of glaciers melding together. One of the largest ice shelves is the Ross Ice Shelf, which is the size of Texas. Whoa!
But because of global warming, only about 40% of Antarctica’s ice shelves remain. One ice shelf, the London, is 12,000 year old. It covers 1,250 square miles (larger than the state of Rhode Island) and is nearly 700 feet thick. In 2002 a large chunk of the London shelf broke off raising the sea level by 200 feet. No kidding!
Interested in reading more about natural wonders? Check out:
This entry was posted on Thursday, December 20th, 2012 and is filed under South America.