It is obvious that mountains must be made of rock. But what kinds of rocks and what kinds of mountains are there? How do the mountains get there in the first place? Let’s know what are mountains made of.
Over the years in which geological thinking has been at its most active, many theories have been put forward to answer these questions. In fact, these types of questions hold the key to some of the most important facts concerning the Earth’s whole history. These are the ideas of mountain building.
What are mountains made of?
If you were asked to name a mountain that you know, which one would it be? Perhaps it would be Mount Everest or Mount Etna or perhaps you might suggest the Harz Mountains of Germany or the Juras of France and Switzerland.
All these mountains are different; made of different types of rock and formed by different processes. Perhaps the simplest and easiest example to understand is the volcano, Mount Etna. Its cone is built up by successive outpourings of lava from the bowels of the Earth.
The Harz Mountains were formed by block faulting, in other words they are the horsts that we have already mentioned.
In these two examples, the volcanic mountain such as Etna can be made of a variety of volcanic materials such as basalt lava or cinders and ash, or more acid, blocky lavas, and the fault mountains can be uplifted blocks of granite such as those that form the Kharas mountains in south-west Africa.
You probably know that Mount Everest is the highest mountain in the world, standing 8848 metres above sea level. (It is interesting to note that the deepest part of the ocean known to man is the Marianas Trench south-east of Japan, which is 11,033 metres deep).
You might also know that Mount Everest does not stand alone but is part of a great chain of the highest mountains anywhere, called the Himalayas, astride the borders of Tibet and Nepal. Among these lofty pinnacles the Abominable Snowman, the yeti, is said to have his icy home.
There are many other such chins of mountains; for example, the Alps or the more modest mountains of the Highlands of Scotland. These are the great fold mountains, made of sediments laid down in primordial oceans and then uplifted by crumpling of the Earth’s crust during periods of crustal shortening.
The fact that these mountains occur in long chins in certain areas of the globe is no accident as you will see later, but is associated with one of the most important concepts of the modern earth sciences, that of continental drift, the almost unbelievable idea of whole continents moving. Hope you must know now what are mountains made of.
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