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Svinafellsjökull, a glacier tongue of the huge Vatnajökull glacier on South-East Iceland. Glaciers weather the underlying bedrock, and the pulverized rock fragments as well as large boulders are relentlessly pushed forward. |
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Jökulsárlón is a large glacial lake to the South-East of the Vatnajökull glacier. When the glacier grew in size, it pushed forward a wall of debris, a so-called moraine. Since the middle of the previous century, the glacier is retreating, and the melting water now first collects in the lake formed between the glacier and the moraine. |
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The Rhone glacier in Switzerland, the source of the headwaters of the river Rhone. The pinkish coloration in the snow field is caused by the unicellular alga, Chlamydomonas nivalis. Glaciers are a strong weathering force, while at the same time they transport rocks and weathered rock material. The melt water often plunges down as a torrential river, which can transport sizable rock fragments. |
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U-shaped valleys, or glacial troughs, have a characteristic U shape, with steep, straight sides and a flat bottom. Such valleys are formed when a glacier travels across and down a slope, carving the valley by the action of scouring. When the ice recedes, the valley remains, often littered with small boulders that were transported within the ice. This U-shaped valley is a well-known touristic attraction, for the road at the head of the valley that winds itself upward in eleven hairpin bends. |
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Granite boulders at the southern tip of the island Öland, Sweden. These boulders have been transported by glaciers during the last ice age. |