Popular science
The layered structure of the Earth refers to the hierarchical distribution of the Earth's interior, which reflects the different chemical, physical, and mineral compositions of the Earth's interior. The Earth's sphere structure is usually divided into the following parts: crust, mantle, outer core, and inner core.
1. The earth's crust
The Earth's crust is the outermost layer of the Earth, and its thickness is uneven, generally thicker on land and thinner in the oceans. The thickness of the earth's crust is about 5-70 km, with the average thickness of the continental crust being about 33 km and the average thickness of the oceanic crust being about 6 km. The earth's crust is mainly made up of rocks, which can be divided into igneous rocks, sedimentary rocks, and metamorphic rocks. The Earth's crust is not homogeneous internally, it is made up of multiple plates, which are in constant motion.
2. The Earth's Mantle
The mantle is the second layer of the Earth, located between the crust and the outer core. The thickness of the Earth's mantle is about 2,800 kilometers and is mainly composed of dense rock-forming materials that appear semi-molten at a certain temperature and pressure. The mantle can be divided into the upper mantle and the lower mantle. The upper mantle is located close to the Earth's crust and is mainly composed of peridotite; The lower mantle is located close to the outer core and is mainly composed of dolerite.
3. Outer core
The outer core is the third layer of the Earth and is located between the mantle and the inner core. The outer core is about 2,200 kilometers thick and consists mainly of liquid iron and nickel. The pressure and temperature conditions of the outer core cause iron and nickel to appear in a liquid state. The flow of the liquid outer core forms the Earth's magnetic field.
Fourth, the kernel
The inner kernel is the innermost layer of the Earth and is located at the very center of the Earth. The core is about 1,300 kilometers thick and consists mainly of solid iron and nickel. The pressure and temperature of the inner core are extremely high, causing iron and nickel to appear solid. The density of the kernel is high, about 107 grams of cubic centimeters, it is the densest substance on Earth.
The Earth's sphere structure exhibits different chemical, physical, and mineral compositions at different depths. This hierarchical structure is due to temperature, pressure, and compositional gradients in the Earth's interior. The structure of the Earth's sphere is important for understanding the formation, evolution, and internal movement of the Earth.