IGNEOUS, the material from which igneous rocks form is the magma, the viscous molten material from the centre of the Earth. If this fluid magmatic material penetrates into the lower parts of the Earth's crust and cools slowly rocks such as GRANITE are formed. If the magma pours out directly onto the Earth's surface volcanic rocks form, as it cools relatively quickly.
 |
| Volcanic Rock |
 |
| Different colours of Granite rock |
SEDIMENTARY, these rocks are formed from a mixture of the weathered debris of igneous, metamorphic and older sedimentary rocks. They are so mixed together that a new type of rock is formed. This takes place over many millions of years and a feature of these rocks is that they contain fossils of plants and animals. LIMESTONE is an example.
 |
| The white marks are the fossils |
METAMORPHIC, metamorphic means change, and this is just what happens with these rocks, they are igneous and sedimentary rocks which under the influence of high pressure and high temperature change into a completely new rock. MARBLE is an example of such a rock. This change can happen due to the movement of tectonic plates or when magma forces itself into parts of the earths crust.
No comments:
Post a Comment