Formation and characteristics

The formation of fold mountains

Formation

• Where an area of sea separated two plates, sediments settled on the sea floor in depressions called geosynclines, and gradually became compressed into sedimentary rock.
• When the two plates moved towards each other the layers of sedimentary rock on the sea floor became crumpled and folded.
• Eventually the sedimentary rock appeared 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

Matterhorn, Zermatt, Switzerland

• 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).