Earth's Scars: Exploring the World's Five Great Rift Systems

5. The West Antarctic Rift System: A Hidden Giant Beneath the Ice

One of the biggest continental rift systems on Earth is hidden behind the huge Antarctic ice sheets: the West Antarctic Rift System. Because of its distant location and high ice cover that hides most of its structure, this great geological feature—which stretches over 3,000 kilometres from the Ross Sea to the Antarctic Peninsula—remains one of the least known rift systems on Earth. Notwithstanding these difficulties, scientific research has shown a dynamic and complicated system that is absolutely important for forming the Antarctic continent. When Antarctica was still a part of the supercontinent Gondwana, the West Antarctic Rift System started to develop around 100 million years ago. Tectonic pressures led the crust to thin and stretch as the continent separated from its neighbours and headed towards its present position over the South Pole. Major volcanic activity preceded this event, which over millions of years has helped to define the area. With some regions lying more than 2,000 meters below sea level, now the rift is defined by a sequence of basins and elevated rocks. The West Antarctic Rift System is notable mostly for its impact on the stability of the West Antarctic Ice Sheet. The geology of the rift influences the distribution of geothermal heat and ice flow, two important aspects that help one to grasp the possible response of the ice sheet to climate change. Among the several subglacial lakes found in the rift system is one of the biggest ones known worldwide, Lake Vostok. Separated from the surface for millions of years, these unusual habitats might contain yet undiscovered types of life and offer clues about the possibility of life on frozen worlds in our solar system.