What is Iceberg?

An iceberg is a large piece of freshwater ice that has broken off from a snow-formed glacier or ice shelf and is floating in open water.Most icebergs are found in the ocean, but are all composed with fresh water, not frozen sea water, since a glacier is frozen snow. Icebergs are white, blue, or green and sometimes even black due to rock materials that were first in the glacier and ended in the sea because of the iceberg. Icebergs can decrease in size because when an iceberg is exposed to heat, like, all other ice, it melts. Icebergs can last at least 10 years, but now the green house effect is causing them to melt a lot faster.

Cause
The are several ways that can cause iceberg to form or calve such as action from wind and waves, the ice shelf grows too large to support part of itself or a collision with an older iceberg.

The link : 1. http://en.wikipedia.org/wiki/Iceberg
2. http://www.internet-at-work.com/hos_mcgrane/ocean/oiceberg.html
3. http://www.esa.int/esaEO/SEM9C9JJX7F_index_0.html