Ingeous rock
- By far the greater part of the Earth's crust is made of two important rocks; these are the granites which make up the coutinentla crust and the baslts which are to be found in the ocean basins. Both of these rocks are igneous in type, that is, they were formed at high tmpertures within the Earth crust. Granite is formed in the USA, Canada, Scandinavia and england-particularly in Devon and carnwall.
Volcanoes
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| Volcanoes |
- There are many other types of igneous rocks apart from granite and bsalt. They contain a variety of minerals and they may be formed in a variety of ways. The malten materials which lies below the surface of the Earth called magma.
- Whenever magma forces its way to the surface, it forms extrusive rocks in some shape or forme.
- The molten rock which spreads out over the Earth's surface and solidifies is called lava..
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