PLANET EARTH Mountains

Moths may seem a meager meal for a bear, but their bodies are rich in fat and can make all the difference in a bear's annual struggle for survival. Another battle is being waged here but on a much longer timescale. These loose boulders are the mountain's crumbling bones.



The Rockies are no longer rising but slowly disintegrating. All mountains everywhere are being worn down by frost, snow and ice. The Alps（阿尔卑斯） were raised some 15 million years ago as Africa, drifting northwards, collided（碰撞） with the southern edge of Europe. These spires are the eroded（侵蚀） remains of an ancient seabed that once stretched between the two continents.



But these are just the Alpine foothills（阿尔卑斯山麓）. The range at its center rises to 3 miles high and is crowned with permanent snows. The Matterhorn（马特峰）, its summit too steep to hold a snow field. Mont Blanc（勃朗峰） - the highest peak in Western Europe. The distinctive jagged shapes of the Alps were carved by those great mountain sculptors - the glaciers（冰川）.



Immense rivers of moving ice, laden with rock, grind their way down the mountains, gouging out deep valleys. They're the most powerful erosive force on our planet. A moulin - a shaft in the ice opened by melt water as it plunges into the depths of the glacier.