Petrography is the science of rocks
The origin of the rocks allows us to classify them: - igneous rocks - sedimentary rocks - metamorphic rocks
1 Magma is mostly formed from all surface rocks as a result of fusion during the subduction of tectonic plates; 2 Igneous rocks crystallize from magma or gases produced by magma when it rises to the surface as a result of tectonic events. 4 Erosion and surface transport decompose the rocks and accumulate sediment in the seas and lakes. 3 Sediments are transformed by diagenesis in sedimentary rocks as a result of increasing temperatures and pressures they face because of the superimposed sediment. 5 Metamorphic rocks are formed by recrystallization of existing rocks due to very high rises of pressure and temperature, most often related to the landfill.