John Muir: The Different Types Of Glaciers

Glaciers have formed nature’s most attractive scenery on this earth. They are enormous icy rivers that often run thousands of feet deep and wide and will run for many miles in length. They cover huge amounts of land and can change land into beautiful mountains with many different features. Glaciers are one of nature’s most powerful forces and have a very slow process. One area where glaciers have been the most notable has been in Yosemite National Park in California. There we can see many glacial features but before we knew how the valley originated there were many different arguments on how the valley originated. In the book Glaciers of California by Bill Guyton, John Muir perfectly combines science and poetry to describe the glaciers in the
Alpine or valley glaciers exist in mountain valleys and they take up the space where a stream once was and then become a glacial stream. An ice sheet is another type of glacier which much larger and can be referred to as continental ice sheets due to their size. They cover the land they rest on and flow in all directions. Another type of glacier is the ice cap is and covers the plateaus and uplands. This type covers completely the surface which it sits on but is smaller than ice sheets mentioned previously. The last type of glacier is the piedmont glacier. This glacier forms when the valley glaciers come out of the mountain valley and covers the bases of mountains.
Due to the pressure of its own weight, the compressive forces and the forces of gravity the ice in glaciers come under so much pressure that the glacier starts to flow or move. There are two types of flow. Plastic flow is flow caused by the internal deformation of ice. The other type of flow is when the entirety of the ice mass slides on the ground. The rate of this glacial flow varies from one glacier to the
It gains ice in the zone of accumulation where ice and snow are accumulated therefore thickening the glacier. But it loses ice in the zone of wastage where the old snow and ice melt. Ice is also lost through calving which is when large masses break off which creates icebergs in the ocean. The movement of a glacier mainly depends on how much a glacier gains or loses ice. When a glacier's zone of wastage is smaller than its zone of accumulation the glacier will then move forward. When these two zones are equal to each other the glacier will stand still. But if the zone of wastage is larger than the zone of accumulation the glacier will move back.In erosion process, glaciers play a key role. When glaciers flow over bedrocks they loosen the rocks and cause them to break off. The do this by seeping into the fractures, freezing and expanding therefore causing the rupture. The flowing glacier will pick up all loose rock and carry them. As glaciers flow over the bedrock it will also polish and smooth them. The grinded rock that is excess become flourlike and becomes part of the glacier. If this rock flour is large enough in quantity it will change the glacier’s color to a more gray shade. The glaciers will also cause scratches in the bedrock; this is known as Glacial Striations. The landforms of Cirques, horns, arêtes, hanging valleys, cirques, moraines and glacial troughs which are landforms that give mountains their beauty are produced