Geography glaciers

• The two main types of glacial erosion are abrasion (the wearing down of rock surfaces) and attrition (the breaking up of rocks).
• Abrasion occurs when rocks on the base of a glacier rub against the ground, causing them to wear away over time.
• Glacier ice is formed from snow that has been compressed over time, resulting in the formation of ice crystals.
• Attrition involves the breakup of rocks into smaller pieces due to their impact with other rocks or debris carried along by the glacier.
• Moraines are ridges of material that have been transported and then left behind by a glacier.
• As more snow falls onto the surface of the glacier, it becomes compacted into firn, which eventually turns into glacier ice.
• Glacial deposition refers to the process whereby sedimentary deposits are formed as a result of the movement of glaciers.
• Glacier ice can be found at different depths within the glacier, with older ice being located deeper inside.
• As glaciers move across land, they can cause significant changes to the landscape through processes such as abrasion and attrition.
• Glaciers can also transport large amounts of sediment and deposit it in areas where the glacier melts or slows down.
• This process is known as deposition and can result in the creation of new features like moraines and drumlins.
• Terminal moraines form at the end of a valley glacier where it meets the plain below.
• There are three different types of moraines: terminal, lateral, and medial.
• Lateral moraines form alongside the sides of a valley glacier as it moves through a valley.
• During summer months, some areas of the glacier may melt, leading to the release of water as well as sediment-laden meltwater streams called glacial outwash.
• The accumulation zone is the area where new snowfall occurs and contributes to the growth of the glacier.
• The ablation zone is the area where melting and sublimation occur, leading to the loss of mass from the glacier.
• Ablation is the process by which glaciers lose mass through melting and evaporation.
• The formation of these features occurs when the glacier moves over rocky terrain, causing rocks and debris to become trapped beneath its base.
• Medial moraines occur when two or more glaciers meet and merge into one larger glacier.
• Drumlin hills are elongated hills that have been shaped by the action of subglacial meltwater channels beneath the surface of the glacier.
• Moraines are ridges made up of accumulated material that form on either side of a valley glacier.
• Medial moraines form between two branches of a bifurcating (splitting) glacier.
• Lateral moraines occur on either side of a valley glacier and are formed by material that has been pushed out from between the two sides of the glacier.
• Hanging glaciers develop when a cirque glacier extends beyond its source basin and becomes isolated by higher ground.
• A cirque or corrie glacier forms within a mountain basin with steep walls that prevent the flow of air downwards.
• Glaciers can be classified based on their shape into four main categories: cirque (corrie) glaciers, hanging glaciers, piedmont glaciers, and ice caps.
• Glaciers store about 75% of freshwater on Earth.
• Terminal moraine forms at the end of the glacier.
• Glacial erratics are large boulders transported by glaciers and deposited at their margins.
• The formation of a cirque involves the removal of rock debris, which is then deposited at the base of the cirque to create a fan-shaped deposit called an end moraine.
• Glacial erosion occurs as water seeps into cracks in rocks and freezes, causing them to expand and break apart.
• Rockfall can be caused by freeze/thaw cycles, where ice expands and contracts inside joints and fractures, eventually breaking off large chunks of rock.
• Ice sheets cover large areas of land and have an average thickness of over 1 km.
• Piedmont Glaciers - Occupy low-lying areas at the foot of mountain ranges
• Ice Caps - Cover large areas of land and have no distinct summit
• Plucking is where blocks of rock are pulled out from undercut cliffs or overhanging ledges.