TECTONIC ACTIVITY- Fold Mountains

The formation of fold mountains

1. Where an area of sea separates two plates, sediments settle on the sea floor in depressions called geosynclines. These sediments gradually become compressed into sedimentary rock.
2. When the two plates move towards each other again, the layers of sedimentary rock on the sea floor become crumpled and folded.
3. Eventually the sedimentary rock appears above sea level as a range of fold mountains.

Where the rocks are folded upwards, they are called anticlines. Where the rocks are folded downwards, they are called synclines. Severely folded and faulted rocks are called nappes.

Characteristics of the Alps

• High mountain ranges, eg Mont Blanc which is 4810m above sea level.
• Glaciated valleys, eg the Rhone Valley.
• Pyramidal peaks, eg the Matterhorn.
• Ribbon lakes, eg Lake Como.
• Fast flowing rivers.
• Contrasting microclimates on north facing (ubac) and south facing (adret) slopes.
• Geologically young (30 – 40 million years old).

Human activity surrounding fold mountains

• Winter sports such as skiing in resorts such as Chamonix.
• Climbing and hiking in the summer months.
• Summer lakeside holidays, eg Lake Garda.
• Agriculture – takes place mainly on south facing slopes and includes cereals, sugar beet, vines and fruits.
• Forestry – coniferous forests for fuel and building.
• Communications – roads and railways follow valleys.
• Hydroelectric power – steep slopes and glacial melt water are ideal for generating HEP. It accounts for 60% of Switzerland’s electricity production.