Science Facts

What Is The Lithosphere Made Of? – Definition & Structure


Lithosphere is a solid layer of rocks that covers the entire earth. However, it has cracks that can be found in the continents and even on the ocean floor. Because of these cracks, the lithosphere is broken down into smaller pieces, and these smaller pieces are known as the tectonic plates. Tectonic plates can be categorized into two primary plates, and the other one is the secondary plates.

There are four interdependent spheres on planet Earth. They are lithosphere, biosphere, hydrosphere, and atmosphere. The names of these fields have come from the Greek world.

What is the lithosphere?

The lithosphere is the solid rocky surface of the earth, including the rocky ocean beds. Lithos is Greek for rocky or landmasses, and sphaira means the Earth’s outermost rigid shell. Literally, lithosphere means rock. The Earth’s continents and Islands are part of the lithosphere.

If you move hundreds of kilometers beneath the Earth’s surface, you will find your lithosphere. So lithosphere is the rigid outer shell of the planet. The earth was formed by powerful geological pressures over millions of years. The earth is composed of several layers like the layers of an onion. Also, Each layer has distinct properties. The lithosphere can shift into earthquakes. The Earth’s crust is made of magma, and it rises to the surface as lava.

Thickness: How thick is the lithosphere? The lithosphere is quite thick. If you start digging the ground, you would have to dig 400 kilometers to get past the lithosphere. It is about 100 km thick, although its thickness is age-dependent.

Temperature: The lithosphere’s temperature range can range from a crustal temperature of zero degrees Celsius or 32 degrees Fahrenheit to an upper mantle temperature of 500 degrees Celsius or 932 degrees Fahrenheit.

Pressure: The lithosphere’s pressure is about 18 GPa and gradually builds up in the thicker regions.

Types: There are two types of the lithosphere. One is the oceanic lithosphere which is associated with oceanic crust. Another is the continental lithosphere which is associated with continental crust.

What is the lithosphere made of?

The lithosphere is made up of the solid rocky crust and the mantle’s uppermost part closest to the surface. It is the coolest and most rigid part of the Earth. Also, it contains minerals and water.

Lithosphere Layers

The layer of the lithosphere & structure: It has three layers which represent the upper, middle, and lower layers. Here are the layers with explanation and structure.

1. Crust: The crust is the uppermost layer of the earth rich in silica, aluminum, and magnesium. Some of which are solid, others melted from the outside in the layers are the crust. It is the first layer on the outside. It’s very thin compared to the other layers averaging about 80 kilometers deep.

The crust is made up of rocks, minerals, chemicals, and elements. There are two crust types: The oceanic crust, which sits under the ocean’s basins, and the other is the continental crust. It is composed mainly of granite rock and much thicker than the oceanic crust. Silica and aluminum are also known as continental crusts.

2. Mantle: The mantle is the second and middle layer of the lithosphere. The mantle is composed of solid and molten rock. The crust and the very top portion of the mantle together make up the lithosphere. Also, It is the rocky surface of the earth. The deeper part of the mantle, which is about 2880 kilometers thick, is believed to be solid rock.

The depth of this layer is about 200 kilometers from the surface. The materials in the semi-liquid are partially motor stains which are called magma. The materials which are found in this mantle layer will be in the form of semi-liquid or molten. There are two layers of the mantle: the Upper mantle and the Lower mantle.

The first one is called the upper mantle or also known as the asthenosphere. Also, The lower mantle is also known as the mesosphere. The contact zone of the crust and the mantle is called moro. Which separates the mantle from the core? It is called Gutenberg discontinuity which separates crust from the mantle.

3. Core: This is the innermost layer of the earth. The most important materials of the core are nickel and iron. The depth of this layer is 6371 kilometers from the earth’s surface. There are 2 cores.

Outer core – The outer core is known as the molten core, whereas the materials are in liquid and molten form. Below the earth’s mantle lies the Earth’s outer core. A layer of molten metals, mainly iron, about 2240 kilometers deep.

Inner core – The inner core is known as the solid core because it will be solid in these materials. The deepest layer is the inner core. A ball of solid metals, mostly iron, about 2,400 kilometers in diameter, although: it seems firm and stable.

The lithosphere is made of several rigid plates called tectonic plates, which slowly move against one another. They are seven major tectonic plates and many smaller plates. And they all float on the Earth’s mantle. These plates don’t stay still but continuously shift in response to the extremely high temperatures and pressures inside the earth. As they shift, the tectonic plates grate against one another. They pull apart and collide with each other.

Most of the shifting can’t be felt by people on earth sometimes though the shifting allows molten lava to make its way to the Earth’s surface in earthquakes and volcanic eruptions. Also, It can be felt by many plate movement has contributed to the shape and position of the Earth’s continents.

Let’s quickly learn why do they float as you move below the Earth’s surface. The mantle has a higher density in comparison to the crust. Also, the mantle is in a liquid state, whereas the crust is in a solid-state. So below the crust, there is a liquid that has a higher density. Therefore, these plates, which have lower density and are solid, are floating over the liquid.

Read More: Why & How Do Volcanoes Erupt? Types, Factors & Effects

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