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The Mer de Glace (Sea of Ice) is a glacier located on the northern slopes of the Mont Blanc massif, in the Alps. At long and deep, it is the longest glacier in France.〔(La Mer de Glace - Chamonix Mont Blanc )〕 ==Geography== It originates at an elevation of where it is fed by the confluence of Glacier du Géant, Glacier de Lechaud, and Cascade du Talèfre, north of Mont Tacul, and descends to . It flows north-north-west between Aiguille du Moine on the east and Trélaporte on the west. Le Grand Dru lies to the north east. It was once easily visible from Chamonix, but has been shrinking and is now barely visible from below.〔 It lies in the Chamonix valley, it was the first place in the valley to have a ready-made tourist attraction. The Mer de Glace, like all glaciers, is constantly renewed by two phenomena: accumulation, notably due to snowfall and ablation, essentially due to melting. The Mer de Glace flows permanently under the effect of its own weight, causing crevasses, seracs or pockets of water to form, depending on the type of ground. The glacier's speed, although not perceptible to the naked eye, is considerable. From more than a year in its upper part, the Mer de Glace moves about per year in the region of Montenvers, which is about one centimeter per hour. When the tension in the ice increases the glacier is deformed and crevasses appear. These are notably transversal and, when there is intense crevasse activity, blocks of seracs appear as the glacier breaks up. These crevasses are of variable depth, depending on their position, and may be as deep as fifty metres. They always form in the same place because of the shape of the glacial valley in which the glacier flows. Disappearing downstream, they are renewed upstream. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Mer de Glace」の詳細全文を読む スポンサード リンク
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