The landscape of Switzerland was largely shaped by the process of glaciation. There a few areas which have been affected by internal earth movement (endogenic) such as vulcanism and faulting. However folding has played a major role towards the formation of the Alps. This is an exogenic process that has led to the formation of major features such as aretes, pyramidal peaks, moraine dammed lakes among other features.

 Glaciation                                                                 

Many regions in the high altitude receive precipitation in the form of snow during the winter season. The level above which there is a perpetual cover of snow is called a snowline. When snow accumulates year after year, it gradually turns into ice masses of the ice sheets.

 

Aletsch Glacier

The Aletsch Glacier, found in Switzerland's Bernese Alps, is the longest valley glacier in the Alps. Glaciers erode the land over which they move and transport large quantities of rock, sand, and other particles along their path. Paolo Koch/Photo Researchers, Inc.

 

Diagram showing a pyramidal peak, Aretes, cirques and other features.

 

A large mass of moving ice is known as glacier. Ice action which is also known as glaciation changes the appearance of the region greatly. Glaciation is the work of ice on the landscape. It involves the processes of erosion, transportation and deposition. This is an exogenic process that has led to the formation of features such as arêtes, pyramidal peaks, moraine dammed lakes among others.

 Glacial Erosion

Erosion by ice consists of three processes which include plucking, abrasion and basal sapping.

Plucking

The tearing away of blocks of rocks which have been frozen into the base and side of a glacier.

Abrasion

This is the process by which the rocks embedded in the glacier erode the valley floor and sides by the scouring action of ice as the glacier moves.

Basal sapping

Is the process through which the rocks between the glacier and valley sides are broken up due to alternate freezing and thawing of water in the rock joints.

Features resulting from glaciation

A number of features result from erosion, the work of ice on the landscape. The most important of these are the aretes, Corries or cirques, tarns among others.

The corrie or cirque or CWM.

A Cirque is a steep-sided rock basin, semi-circular in plan, cut into valley heads and mountain sides. Many are very small but some have backwalls hundreds of metres high.

 

Cirques usually develop from Nivation hollows. Through the process of Nivation, intensive shattering of highland slopes tend to produce depressions or pre-glacial hollows where ice accumulates.

Water freezes in the hollows and thaws or melts. Consequently there is expansion and contraction that break the rocks through the process of plucking. Plucking results in the backwall becoming steep. Abrasion widens and deepens the hollows by scouring process using the materials embedded in ice. This results into a steep sided semi-circular basin called cirque as seen in the diagram below.

A tarn

A tarn is a lake found in a corrie or cirque. Sometimes in climate may cause melting of ice on the mountain side. The melted water usually occupy the corrie forming a tarn.

Pyramidal Peak:  This is a sharp rock pinnacle which is steep-sided rounded by a system of radiating arêtes. It is formed from glacial erosion where cirques are first formed and the backwall recession of two or more cirques cutting back into the original mountain or upland leading to the formation of a sharp rock pinnacle protruding above the ice through a system of radiating arêtes. Since pyramidal peaks develop from radiating arêtes, which in turn develop from cirques, then processes of plucking and abrasion are important in their formation.

 

Diagram below showing the formation of Aretes and pyramidal peak.

 

An Arête: Is a narrow, steep sided rocky ridge, separating two cirques. It results from the glacial erosional processes of plucking and abrasion which lead to the formation of cirques. The backwall recession of two adjacent cirques lead to the formation of a sharp knife-like ridge which is called an arête separating two cirques.

 

Diagram showing a pyramidal peak, Aretes, cirques, truncated spurs, hanging valleys, U-shaped valley and other features.

Glacial Troughs / U-shaped valley:  This is a broad flat bottomed, steep sided valley with a U-shaped cross profile. It is formed when pre-existing main river valley is filled with glaciers. The valley is widened and deepened through freezing and thawing, plucking and abrasion. 

 

Interlocking spurs are truncated to form a steep sided U-shaped valley. An example is the Lauterbrannen valley.

Hanging valley: 

This is tributary valley lying above the main valley. Hanging valley descends steeply into the main valley by waterfall. Formed because during glaciation, tributary valley is occupied by a small volume of glacial compounds to the main valley. This smaller glacier can not deepen and widen the valley to the same level of the main U-shaped valley thereby it's floor left hanging above. The floor of the main valley and hence the name hanging valley.

Truncated Spurs

These are spurs with steep edges into the valley. They are formed when the amount of ice in a valley increases by the addition of ice at the rears and by tributary glaciers entering the main valley. This increases the erosion power of a glacier. This results in a glacier deepening, straightening and widening of a river valley and the former interlocking spurs are plucked / planned off by freeze-thaw action into truncated spurs.

Moraine

This is the material carried by a glacier as it moves along a valley. It consists of rocks from the sides and bed of the valley which become embedded in the ice. There are four (4) types:

Terminal moraine:  This is the one at the end of the glacier. It occurs at the point where valley or mountain glacier melts and deposits material eroded upstream.

 

Lateral moraine:  This is the moraine deposited on the sides of the glacier.

Medial moraine:  This is formed when the glaciers join and their inner lateral moraines join together to give a medial moraine.

Ground moraine:  This is the moraine found at the bottom of the glacier.

 

Glacial features

 
Importance of glaciation                                                                    

Glaciation has led to the development of tourism through creation beautiful scenery that attracts tourists.

 
The Swiss National Park in the canton of Graubünden.

The water falls resulting from glaciation have been utilized for power generation.

There melting ice ensures a steady supply of water for power production, and irrigation.

Moraine deposits lead to fertile soils for example the Central plateau where agriculture is an invariable activity.

There is recreation. This enables the people of the area to carry out winter sports such as skating and skiing.

On the other hand poor soils have developed. Glaciation resulted into very thin soils in the Swiss Alps. This has limited agriculture activities in the country.

There is a danger of avalanches which are destructive to life, property and the agricultural sector.

 
Lake Lugano

The scenic beauty of Lake Lugano is enhanced by its setting on the southern fringe of the Alps. The lake lies in both Italy and Switzerland and is a popular destination for tourists and retirees because of its mild Mediterranean-style climate.