The process …show more content…
Earth has a core composed of two distinct parts: the inner core and the outer core. Both parts of the core are made up of mostly iron and some nickel. The difference is that those minerals in the inner core are solid and the same minerals in the outer core are liquid. The subsequent layer is the mantle which is sitting on top of the outer core. This layer is by far the thickest layer of Earth. Similar the core, the mantle contains mostly iron but in the form of silicate rocks. The mantle can also be divided into two portions, the upper mantle and the lower mantle. The lower mantle is completely solid since the pressure is too excessive for it to melt and flow. The upper mantle is also known as the asthenosphere, which flows as convection currents. Convection occurs in all fluids and is the rising of warm particles and sinking of cool particles. This convection flow of the asthenosphere has a large impact on Earth 's lithosphere, the outermost layer of the planet. The lithosphere contains both the crust and a small portion of the upper mantle. The lithosphere is very rigid; it does not flow like the asthenosphere. The crust itself, which is contained in the lithosphere, can also be divided into two parts, the continental crust, and the oceanic crust. The continental crust is composed mostly of granite unlike the oceanic crust which consists of a volcanic lava rock called basalt. Basaltic rocks of the ocean plates are much denser and heavier than the granitic rock of the continental plates. Lying above the lithosphere is the liquid hydrosphere, containing 71% of the Earth 's surface. Finally, the Earth 's atmosphere is a thin layer of gases that surrounds the Earth. Atmosphere is composed mostly of nitrogen, oxygen, and a combination of other