Rock formation

• Igneous come from the Latin word ignis which means heat or fire.
• Igneous rocks are formed when the magma or lava cools and solidifies. It may happen below (plutonic) or above (volcanic) the Earth’s surface.
• Intrusive igneous rocks are formed when the magma hardens before an eruption occurs. Different rock materials allow the formation of intrusive igneous rocks.
• Granite is used in floor tiles and monuments. most common Intrusive igneous rock
• Extrusive igneous rocks are formed when the lava cools and solidifies on the Earth’s surface.
• The texture of these rocks is finer as compared to the intrusive igneous rocks. Due to slow cooling of the lava, large crystals are formed on the rocks.
• ·       Basalt is used for construction purposes such as pavements, railroads, and road base. Most Common volcanic rocks
• Metamorphismis the process of change in the form and structure of rocks due to intense heat and pressure
• Metamorphism comes from the Greek word metamorphoun meaning transform or change shape. The rocks that undergo metamorphism are converted to metamorphic rocks.
• Contact metamorphism is the process where the country rock adjacent to the igneous intrusions is altered by the high heat coming from the intrusions. 
• Country rocks are rocks surrounding the igneous intrusions. 
• Igneous intrusions form when molten magma moves and seeps through fractures and in between crystals of rocks.
• The zone of metamorphosis that surrounds the intrusions is called halo or aureole
• ·       Some examples of rocks that undergo contact metamorphism include marble and emery rock.
• Dynamic metamorphism is the process where rocks along the fault zones are altered due to high pressure
• ·       The rocks that are formed with this type of metamorphism are called mylonites. Mylonites are compact, fine-grained rocks with thin laminations or layers.
• ·       Regional metamorphism is the most common form of metamorphism that occurs in broad areas. It is caused by high temperature and pressure that resulted from the thickening of the crust and plate tectonics.
• Compression causes the rocks to push or to collide with each other. This can make the rocks come together or make the plates rise. Mountains and hills could be formed when two plates collide. 
• Tension is the opposite of compression. The tension force pulls the rocks away from each other. This force created continental drifts and mid-ocean ridges. It moved the oceanic crust away from each other that resulted in the rising of less dense rocks coming from the mantle. 
• Shear force pushes the crust in different directions. Shearing results in the breaking of the large parts of the crust into smaller sizes. This force always happens along the plate boundaries
• . Plate boundaries are the location where the two plates meet.
• When the two plates rub each other and move in opposite directions, it creates friction. This friction leads to the shaking of the Earth’s ground or earthquake.