Unit 1: Physical Environment Glaciated Landscapes Corries Corries are bowl-shaped hollows high up in the mountains. They are formed in the following way: Snow collects in a hollow on a mountainside (usually on the north facing side of a mountain because here it is less sunny). As more snow falls it is compressed to form ice. The ice then begins to move downhill under gravity. As the ice moves downhill it erodes the hollow making it deeper. The ice erodes the backwall by the process of plucking and freeze-thaw weathering, making it steep and jagged. The ice erodes the base by the process of abrasion making it smooth. When the ice melts away corries are often filled with meltwater and so form corrielochs or tarns. Arêtes and Pyramidal Peaks Arête Where two corries form back to back the rock between them is plucked away to form a narrow ridge. This steep and narrow ridge is called an arête. Pyramidal Peak Where three or more corries form back to back the rock between them is plucked and weathered into a sharp point, usually the highest point in the area. This sharp point is called a pyramidal peak.
U-Shaped Valleys When a glacier flowed out from a corrie it continued to move downhill. It usually took the steepest route, which, in most cases, was an old river valley. This led to the formation of a U-shaped valley. Before the Ice Age rivers in mountains ran down V-shaped valleys. During the Ice Age glaciers flowed down these same valleys. The ice was so thick that it was able to pluck and abrade the valley sides as well as the valley floor. This caused the V-shaped valley to become steeper and deeper, taking on a more U-shaped appearance. After the Ice Age we were left with large U- Shaped valleys with very steep sides and a wide, flat base. The steep sides are called truncated spurs. The flat base often has a river flowing through it called a misfit stream (so called because it is too small to have formed such a very wide valley). The base will also often have a ribbon lake. This is where the glacier was able to erode more deeply than elsewhere.
Hanging Valleys Hanging valleys were formed in the following way: A thick glacier flowed through the main river valley, while a smaller glacier flowed through a tributary valley. The thick glacier eroded more deeply than the small glacier. This is because the smaller tributary glacier contained much less ice and so was less powerful. Because the smaller tributary glacier could not erode its valley as deeply as the main glacier it was left hanging above the main valley. After the Ice Age, when rivers took over, the hanging valley would often become a waterfall.
Glacial Landforms on Maps Landuse in Glaciated Uplands Hill-sheep farming. The slopes are unsuitable for farm machinery. It is impossible to grow crops because the soils are too thin, temperatures are low and there is little sunshine to ripen crops. So the only type of farming possible is hill-sheep farming. Forestry. Coniferous trees (pine, spruce, larch, fir) grow well in cold climates and thin, poor soils. Forestry is profitable and worthwhile since the land is of poor quality and is difficult to build on. HEP. Because glaciated upland areas often receive large, reliable amounts of rainfall and have steep slopes this makes them good locations for Hydro Electric Power stations. Tourism and Recreation. The beautiful scenery of glaciated uplands attracts sightseers, hillwalkers, mountaineers, bird watchers, water sports enthusiasts and anglers.
Glossary of Important Terms Moving ice erodes in two ways: Plucking ice freezes onto rocks and plucks away loose fragments leaving a rough, jagged surface. Abrasion fragments embedded in the bottom of the ice scrape and smooth the rock over which it is moving. Freeze-thaw action (frost shattering) meltwater enters cracks in the rock, freezes and expands. This forces the crack slightly wider. When this freeze-thaw action is repeated many times, pieces of rock are broken off. They often build up at the foot of slopes as scree.