Since ancient times, people have been intrigued by what lies beneath the Earth's crust and have sought an explanation. Where do minerals come from? How many types of rocks are there? What are the parts of the Earth?
These are many of the questions that have been asked throughout history. If you want to know more about the parts of the Earth here we tell you more about them.
The branch of geology that studies the Earth's structure and its different layers is internal geodynamics . Our planet is made up of several elements that make life on Earth possible. These elements are: solid, liquid, and gas. These elements exist in different layers of the Earth.
There are many ways to classify the parts of the Earth. In one classification, they are called spheres . These include the Atmosphere, the Hydrosphere, and the Geosphere. The Geosphere encompasses all the structures and different internal layers of our planet . These layers are divided into two categories: the outer layer and the inner layer. In our case, we will focus on the Earth's internal layers; that is, the Earth's surface will be our starting point.
parts of the earth
To begin describing the parts of the Earth, we must make two distinctions. First, standards were established for the chemical composition of the different layers of the Earth. Based on chemical composition, we find the crust, the mantle, and the core . This is called a static model . Another criterion is based on the physical properties of the layers, also called a mechanical behavior model . These include the lithosphere, the asthenosphere, the mesosphere, and the endosphere.
But how do we know where a layer begins or ends?
Scientists have found different ways to understand the types of materials and distinguish layers through discontinuities. These discontinuities are regions in the Earth's inner layer where the type of material contained in that layer changes abruptly — that is, its chemical composition or the state in which an element is found (from solid to liquid). First, we will classify the Earth's layers based on the chemical model; that is, the Earth's layers will be: Crust, Mantle, and Core.
Earth's crust
The crust is the outermost layer of the Earth. It has an average density of 3 g/cm³ , which is only 1,6% of the Earth's total volume . It is divided into two distinct regions: continental crust and oceanic crust.
Continental crust
The continental crust is thicker and has a more complex structure . It is also the oldest crust, representing 40% of Earth's surface . It consists of a thin layer of sedimentary rocks, the most prominent of which are clay, sandstone, and limestone. It also contains silica-rich plutonic igneous rocks similar to granite. Interestingly, most of the geological events that have occurred in Earth's history are recorded in the rocks of the continental crust. This is well known because these rocks have undergone many physical and chemical changes throughout history. This is evident in mountains, for example, where we can find ancient rocks that can be up to 3.500 billion years old. Furthermore, you can learn about mountains and their formation in relation to the crust.
oceanic crust
On the other hand, we have the oceanic crust. It is thinner and has a simpler structure. It consists of two layers: a very thin layer of sediment and a layer of basalt (which are igneous volcanic rocks). This crust is younger because basalt is constantly forming and breaking down, so the rocks of the oceanic crust are no more than 200 million years old. At the bottom of the crust is the Moho discontinuity . This discontinuity separates the crust from the mantle. It is located at a depth of about 50 kilometers.
Manto
The mantle is one of the Earth's layers, extending from the bottom of the crust to the outer core . It begins behind the Moho and is the largest layer of the planet, comprising 82% of Earth's total volume and 69% of its total mass. The mantle is divided into two layers by the Repetti discontinuity . This discontinuity occurs at a depth of approximately 800 kilometers and marks the boundary between the upper and lower mantle. Within the upper mantle lies the "D layer ." This layer extends to a depth of roughly 200 kilometers and is characterized by 5% to 10% partial melting. This melting causes heat to rise from the core through the mantle. As the heat increases, the mantle rocks heat up, sometimes rising to the surface and forming volcanoes. These are known as "hot spots."
The composition of the mantle can be known by these tests:
- Hay two types of meteorites: the first is formed by peridotite and iron.
- Existing rocks on the surface of the Earth that have been removed from the mantle due to tectonic movements.
- Volcanic Chimneys: They are very deep circular holes through which the magma rises and exposes them. It can have a length of 200 kilometers.
- seismic wave shortening tests as they pass through the mantle they suggest that there is a phase transition. Phase transitions include changes in mineral structure. At the end of the mantle we find the Gutenberg discontinuity. This discontinuity separates the mantle from the core and sIt is located about 2.900 kilometers deep.
Core of the Earth
It is the deepest part of the Earth. It extends from the Gutenberg discontinuity to the Earth's center. It is a sphere with a radius of 3.486 kilometers, so its volume is 16% of the Earth's total volume . Its mass is 31% of the Earth's total mass because it is composed of very dense material. In the core, the Earth's magnetic field is created by convection in the outer core, which is molten around the solid inner core. Its temperature is very high, around 5000–6000 degrees Celsius, and the pressure is equivalent to one to three million atmospheres.
The Earth is divided into an inner core and an outer core , the difference being defined by the Vicht secondary discontinuity. The outer core , whose depth ranges from 2.900 to 5.100 kilometers, is molten. The inner core , on the other hand, extends from a depth of 5.100 kilometers to about 6.000 kilometers from the Earth's center and is solid.
It is composed primarily of iron, 5-10% nickel, and smaller proportions of sulfur, silicon, and oxygen. Tests that help determine the composition of nuclear components include:
- very dense materials, for example. Due to their high density, they remain in the inner core of the Earth.
- iron meteorite.
- The lack of iron on the outside of the crust. This tells us that the iron must be concentrated inside.
- Along with the iron inside the core, it forms Earth's magnetic field.
This classification comes from a model that takes into account the chemical composition of different parts of the planet and the elements that make up its layers. Now we will understand the division of Earth's layers from the perspective of Earth's mechanical behavior , that is, from the perspective of the physical properties of the materials that compose it.
Parts of the Earth according to the mechanical model
In this model, the layers of the earth are divided into: Lithosphere, Asthenosphere, Mesosphere and Endosphere.
Lithosphere
It is a rigid layer about 100 kilometers thick that includes the upper layers of the crust and the mantle. This rigid layer is the lithosphere that surrounds the Earth.
Asthenosphere
It is the plastic layer corresponding to most of the upper mantle . Convection occurs within it, and it is in constant motion. It is of great importance in tectonics. This motion is caused by convection , a change in the density of the material.
Mesosphere
It is located at a depth of between 660 kilometers and 2.900 kilometers . It forms part of the lower mantle and part of the outer core of the Earth. Its boundaries are defined by Wiechert discontinuities.
Endosphere
This includes the aforementioned Earth's inner core . As you can see, scientists have been studying the Earth's interior through various tests and experiments to learn more and more about the planet we live on.
As you can see, scientists have been studying the interior of the Earth through various tests and trials to learn more and more about the planet we live on. To compare what little we know about the interior of the Earth, we need only imagine the Earth as an apple. Well, with our advanced technology, the deepest drilling depth that has been achieved is about 12 kilometers. Comparing the Earth to an apple is as if we only peeled off the last layer of the entire apple, and the seed in the middle is equivalent to the core of the Earth. I hope this information has been helpful.
