Dry Valleys
          One of the strangest place in Antarctica are the Dry Valleys in Victoria Land. They consist of three main valleys covering an area of 3000 km² that were once occupied by glaciers. Once free of the glacial ice, the Dry Valleys became selfperpetuating. The exposed surface absorbs enough heat from the sun to evaporate the winter snows and the cold, dry winds blow off any snow that remains. For at least two million year no rain has fallen here. This cold, rocky desert is the closest thing to Mars on earth, and NASA has sent astronauts there for training in extra-terrestrial living.

          There are abstract sculptures of rock, form by the windblown sand and snow, they are called ventifacts. To meet mummified animals is also very usual, because seals and penguins occasionally wander into the valleys. There the extremely dry and cold condition preserve their bodies up to 3000 years.

          An other feature of the Dry Valleys is the saline lakes, which are fed for a few weeks each year by meltwater streams. There the water evaporates and left the salt and other minerals in the sea. During the past 10,000 years enough salt has accumulated to make several of the lakes saltier than the sea. Each time water evaporates from the top of the lake, all the dissolved salts are forced to the bottom where they form a dense brine. Fresh water does flow in at the top, but the difference in the density of the two waters is too great to allow them to mix, except by the very slow process of diffusion.

Lake Vanda
          In the case of Lake Vanda, solar heating has raised the temperature of the saltiest water at the bottom of the lake to 25°C, whereas at the top of the lake there is a layer of ice some 4m thick. This amazing phenomenon occurs because the ice crystals in the ice layer are aligned vertically as a result of the layer of ice constantly freezing underneath and evaporating from the top. The ice crystals act as light pipes which transmit sunlight down into the very clear water beneath.

Sea ice

Weather