Asthenosphere and lithosphere

Structure of the earth

Earth structure includes crust, mantle, core, hydrosphere, atmosphere, magnetosphere.

The Core is the inner part of the earth, it is the center of the Earth; it’s under extreme pressure. It consists of iron and nickel. Relative temperature is from 2,000C to 5,000C. Density: 10 to 13 times denser than water. What does the core consist of? OUTER CORE is area of molten metal that surrounds the inner core. Because the earth rotates, the outer core spins around the inner core and that causes the earth's magnetism. It is in liquid state. INNER CORE is a dense ball of iron and nickel, because of the intense pressure this part is in solid state.

The Mantle is the portion of the interior beyond the crust. It begins about 6 miles (10 km) below the oceanic crust and about 19 miles (30 km) below the continental crust. It consists of silicon, oxygen, iron, and magnesium. Relative Temperature varies from 870C to 2,200C. Density: 3.3 to 5.5 times denser than water. Upper portion of the mantle is considered to be extending up to 400 km. It is the main source of magma that finds its way to the surface during the volcanic eruption. It has a density higher than the crust (3.4g/cm).

Asthenosphere and lithosphere

What does the mantle consist of? ASTHENOSPHERE is the lower mantle extends beyond the asthenosphere. It is in solid state. Asthenosphere is a thin semifluid layer of the earth (100-200 km thick), below the outer rigid lithosphere, forming part of the mantle and thought to be able to flow vertically and horizontally, enabling sections of lithosphere to subside, rise, and undergo lateral movement

LITHOSPHERE is the rigid layer formed from the uppermost part of the mantle and the crust together. Outermost shell of a rocky planet has in average 100 km thick. On Earth, it comprises the crust and the portion of the upper mantle that behaves elastically on time scales of thousands of years or greater. There are two types of lithosphere: oceanic lithosphere, which is associated with oceanic crust and exists in the ocean basins and continental lithosphere, which is associated with continental crust.

The lithosphere is always moving, but very slowly. It is broken into huge sections called tectonic plates. The extreme heat from the mantle part of the lithosphere makes it easier for the plates to move; this is similar to how iron is bendable once it's heated. The movement of the lithosphere, called plate tectonics, is the reason behind a lot of Earth's most dramatic geologic events. When one plate moves beneath another, or when two plates rub together, they can create earthquakes and volcanoes.

Plate tectonics may explain why we have continents. Scientists believe the continents used to be one major landmass called Pangaea, which separated because the lithosphere broke apart. There is evidence to support this theory. For example, the eastern coast of South America and the western coast of Africa look like they would fit together. And even though they are separated by an ocean, similar animals and plants are found in both regions.