Our planet consists of several concentric layers. The top layer - the crust has an uneven thickness. In the mountainous areas of the continents it reaches 70-90 kilometers, and in oceanic areas significantly narrows down to 7-10 miles. The main species that make up the earth's crust, is the oxides of silicon, aluminum, iron, alkali metals. Continental crust has two layers: top, granite, and lower, bazaltovi. In the composition of the continental crust consists of rocks that are older than 3 billion years. Oceanic crust has a single layer. It consists of basalts - silicate rocks containing calcium, magnesium, iron, sodium. The age of the oceanic crust - 100-150 million years
Under the crust is the mantle. It takes about 82% of the total Land. The mantle is divided into two layers: the top and bottom. The upper layer of the mantle together with the earth's crust forms a solid shell of the Earth is called the lithosphere. Beneath the lithosphere is the asthenosphere, which is composed of the rocks, which are in a partially molten state.
In the depths of the planet "hidden" core composed of external, liquid layer and the inner, solid. The outer layer represents the flow of molten iron and Nickel. The inner layer is also composed of iron-Nickel alloy, which, despite the high temperature, is in the solid state, because of the enormous pressure in the center of the Earth.