What is sediment and debris, and what role does it play in the way sedimentary rock forms?

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Sediments are pieces of rock that come from other rocks that were eroded or broken by wind, water or other mechanical forces. Debris are pieces of other materials that were also swept away.

When these sediments and debris settle, they create layers. These layers are called beds. In time, several layers of other sediments and debris form on top of each other which press down onto the previous layers. Because of the pressure from the weight of the newer layers, the sediments and debris are pressed together and go through cementation. These then produce sedimentary rocks.

Metamorphic rocks form when rocks undergo heat and pressure. The heat comes from the friction resulting from the pressure. The heat can also come from radioactive decay. The rocks then slowly bake into new rocks called metamorphic rocks.

Igneous rocks form when magma and lava cool down. Magma is molten fluid found beneath the surface of the Earth. Lava is magma that has reached the surface of the Earth. When they cool down, they crystallize which make igneous rocks.

The difference between intrusive and extrusive igneous rocks is that one is made beneath the Earth and the other is made on the surface of the Earth. When magma cools, it takes a long time and the product of this cooling are intrusive igneous rocks. On the other hand, extrusive igneous rock is the result of lava cooling, which does not take as long to cool down because it occurs on the surface of the Earth.

Examples of the following types of rocks:

Sedimentary: limestone, sandstone, siltstone
Metamorphic: Marble, gneiss, slate
Igneous: Gabbro (intrusive), granite (Intrusive), obsidian (extrusive)