Geology of the Antarctic

The Antarctic continent is located on a continental plate called the Antarctic Plate.Click to enlarge
The Antarctic continent is located on a continental plate called the Antarctic Plate.
Source: Fritz Hertel/UBA

When one considers the mile-thick ice shields which cover the Antarctic continent today, it is hard to imagine that Antarctica used to be fertile land and completely free of ice. Some 170 million years ago Antarctica was still part of the Gondwana supercontinent - until it broke up and Antarctica drifted south and slowly began to freeze over.

The continent Antarctica was a part of the supercontinent Pangaea, which broke up more than 200 million years ago into a northern part (Laurasia) and a southern part (Gondwana). According to Alfred Wegener's theory of continental drift (1912), Laurasia and Gondwana gradually broke up beginning in the Mesozoic era to eventually become the present-day continents. Convection currents in the Earth's interior continue to move the continental plates a few centimetres per year. As a result of continental drift, Antarctica moved to its current position at the South Pole.

Antarctica consists of two very geologically different regions. East Antarctica is a continuous land mass covered by ice. The basement is made up of gneiss rock up to 3.8 billion years old which is covered by younger volcanic rock and sediment. West Antarctica is an island archipelago covered by ice. The Transantarctic Mountains separate the two regions from one another. The mountain range extends across the continent and forms a tectonically active region. The southernmost active volcano in the world, Mount Erebus (3,794 m), is on the edge of the mountain range.

These facts and findings are based on modern measuring techniques, including radar and satellite exploration and seismic testing, which make it possible to 'take a look' under the ice.