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FOLD MOUNTAINS

What are they?Long High mountain ranges caused by sediment being forced upwards in folds.

Over periods of time when the earths movement is quiet, layers of sedimentary rock form huge depressions called geosynclines. For example the sea of Tethys that formed the alps. Over many years sediment built up on the sea bed, and the layers were compressed to form rock. When the tectonic plates moved, the sedimentary rock was forced upwards in a series of folds.

What do they look like?The folds can be simple, from anticlines (simple upfolds) or synclines (simple downfolds) ~~~They can also be over folds, when the anticlines have been pushed over.Nappes are formed when there is a fault, which makes it severely folded.

Where do they occur?They occur at destructive plate margins, when sediment is pushed upwards, or conservative plate margins, where an earthquake will jerk the plates, making the land crumpled and ridged.

EXAMPLESThe Alps, the Himalayas, the Rockies and the Andes

Uses of a fold mountainThe Alps is an example of a fold mountain, formed from the sea of Tethys.The people have adapted to living here:They use the steep slopes and snow for skiing and to develop the tourist industry, which increases the areas incomeOnly mountain goats can get to the steep tops of the mountainsIn summer cattle are moved to the higher slopes, but in winter they are kept in a shed at the bottom of the mountain, fed on last summers cropsThey have built villages on the valley floor because it is easier to build and also offers some protection from the extreme weather conditions.The climate can be very harshThere can be avalanches, so avalanche shelters and automated dynamite systems have had to be installed to ensure they are not a big threat.The soil quality is thin, and has very acidic soild, so it is difficult to grow crops, but cofigerous trees can stand the acidic soils, and are useful for providing building materials and fuelwood.Tunnels are built through mountains to make access easier.Dams and resevoirs are built in the valleys to provide hydroelectric power.The southern facing slopes can be used to grow grapes, but the northern facing slopes too in the shade.

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