The earth is made up of four layers. They each have distinct characteristics about them. The different layers of the earth include the crust, mantle, and the core that is divided into two parts, the outer core and the inner core. Each of the layers has differences in chemical composition and physical properties.
The crust is the first layer of the earth and is made up of two types of crust, oceanic and continental crust. Oceanic crust is below the oceans. There the crust is 4-7 miles thick. The rocks of the oceanic crust are very young compared with the rocks of the continental crust. The rocks of the oceanic crust are not older than 200 million years. The material of which the oceanic crust consists is for the greater part basalt. Basalt has a dark, fine and gritty volcanic structure. It is formed out of very liquid lava, which cools off quickly. The earth's crust is the thickest below the continents, with an average of about 20 to 25 miles and with a maximum of 45 miles. The continental crust is older than the oceanic crust; some rocks are 3.8 billion years old. The continental crust mainly consists of igneous rocks and is divided into two layers. The upper part mainly consists of granite rocks, while the lower part consists of basalt and diorite. Granite is lightly colored, coarse-grain, magma. Diorite has the same composition, but it's scarcer than granite and is probably formed by impurities in the granite-magma.
The layer above the core is the mantle. It begins about 6 miles below the oceanic crust and about 20 miles below the continental crust. It is about 1,800 miles thick and makes up nearly 80 percent of the Earth's total volume. Science deals with the structure of the mantle in two different ways. One way is based on its chemical construction, the other on the way layers stream or move. The mantle is made up of asthenoshere and the lithosphere. The tough liquid part of the outer mantle is the asthenosphere. The lithosphere is the stiffer part of the outer mantle and the crust. The lithosphere 'floats' on the asthenosphere, like ice on water.
The center part of the earth is the core. This part of the earth is about 1,800 miles below the earth's surface. The core is a dense ball of the elements iron and nickel. It is divided into two layers, the inner core and the outer core. The inner core is solid and about 780 miles thick. The outer core is so hot that the metal is always molten, but the inner core pressures are so great that it cannot melt, even though temperatures there reach 6700ºF.The outer core is about 1,370 miles thick. Because the earth rotates, the outer core spins around the inner core and that causes the earth's magnetism.
The journey through the earth is made up of four different layers with different characteristics about them to make them different from each other. The four different layers include the crust, mantle, and the core that is divided into two parts or layers the outer and inner core.