The large icebergs break off from the Antarctic ice shelf. They then swim North and are driven by the East-West flow through the Polar Ocean. Their speed is about 12 km per day. If an iceberg reaches the Antarctic Convergence, their direction reverse because of the West Wind Drift – they swimm from West to East.
Icebergs forms from valley glaciers (weird forms) and from the inland ice (tabular icebergs). The largest tabular icebergs is huge: 150km * 40km. The largest part of the iceberg is under water and only 15-20% is visible. There are 3 different iceberg types depending on their age:
Tabular icebergs: These are young icebergs. Their surface is flat and smooth.
Uneven icebergs: These icebergs have long been exposed to erosion. The parts above the water level are usually pointed, but there are also even parts.
Rounded icebergs: These represent the oldest iceberg type. They have been almost completely rounded by erosion. Some of these icebergs become unstable and tip over.