An explanation of the geological processes which lead to the formation of different types of rock.
- There are three types of rock: sedimentary, igneous and metamorphic.
- Sedimentary rock forms when deep layers of mineral and organic particles are compacted over millions of years, e.g sandstone.
- Igneous rocks form when magma cools to a solid, e.g basalt.
- Metamorphic rock is formed when rock is subject to heat and pressure, e.g. slate is produced from shale hardened as pressure and heat have rearranged the layers.
Yosemite Valley, California –
Despite their variety, all rocks are simply aggregates of mineral grains.
Halong Bay, Vietnam –
The Grand Canyon, Arizona –
The exact type of minerals, the size of the grains, and how the rocks were formed, all affect their appearance and their properties.
Granite has tightly interlocked grains that give ...
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