The Earth’s mantle is the most important part of our planet since it is here that most of the substances are concentrated. It is much thicker than the rest of the components and, in fact, takes up most of the space about 80%. Scientists have devoted most of their time to studying this particular part of the planet.
Structure Mantle of the Earth
Scientists can only speculate about the structure of the mantle since there are no methods that would unambiguously answer this question. But, the conducted studies made it possible to assume that this part of our planet consists of the following layers:
- the first, the outer one, occupies from 30 to 400 kilometers of the earth’s surface;
- the transition zone, which is located immediately behind the outer layer according to scientists, goes deep into about 250 kilometers;
- the lower layer its length is the largest, about 2900 kilometers. It starts right after the transition zone and goes straight to the core.
It should be noted that in the mantle of the planet there are such rocks that are not in the earth’s crust.
It goes without saying that it is impossible to determine exactly what the mantle of our planet consists of since it is impossible to get there. Therefore, everything that scientists manage to study happens with the help of fragments of this area, which periodically appear on the surface.
So, after a series of studies, it was possible to find out that this part of the Earth is black and green. The main composition is rocks, which consist of the following chemical elements:
In appearance, and in some ways even in composition, it is very similar to stone meteorites, which also periodically fall on our planet.
The substances that are in the mantle itself are liquid, and viscous since the temperature in this area exceeds thousands of degrees. The temperature drops closer to the Earth’s crust. Thus, a certain circulation occurs those masses that have already cooled down go, and those heated to the limit go up, so the process of “mixing” never stops.
Periodically, such heated flows enter the very crust of the planet, which they are assisted by active volcanoes.
Ways to study Earth’s mantle
It goes without saying that layers that are at great depths are quite difficult to study, and not only because there is no such technique. The process is further complicated by the fact that the temperature rises almost constantly, and at the same time, the density also increases. Therefore, we can say that the depth of the layer is the least problem, in this case.
However, scientists still managed to advance in the study of this issue. To study this part of our planet, geophysical indicators were chosen as the main source of information. In addition, during the study, scientists use the following data:
- seismic wave speed;
- characteristics and indicators of electrical conductivity;
- the study of igneous rocks and fragments of the mantle, which are rare, but still manage to be found on the surface of the Earth.
As for the latter, it is diamonds that deserve special attention from scientists in their opinion, by studying the composition and structure of this stone, one can find out a lot of interesting things even about the lower layers of the mantle.
Occasionally, there are mantle rocks. Their study also allows you to obtain valuable information, but to one degree or another, there will still be distortions. This is due to the fact that various processes occur in the crust, which is somewhat different from those that occur in the depths of our planet.
Separately, we should talk about the technique by which scientists are trying to get the original rocks of the mantle. So, in 2005, a special vessel was built in Japan, which, according to the project developers themselves, will be able to make a record deep well. At the moment, work is still underway, and the start of the project is scheduled for 2020 there is not so much to wait for.
Now all studies of the structure of the mantle take place within the laboratory. Scientists have already established for sure that the lower layer of this part of the planet, almost all consists of silicon.
Pressure and temperature of Earth’s mantle
The distribution of pressure within the mantle is ambiguous, in fact, as well as the temperature regime, but first things first. The mantle accounts for more than half of the planet’s weight, or more precisely, 67%. In areas under the earth’s crust, the pressure is about 1.3-1.4 million.atm., at the same time, it should be noted that in places where the oceans are located, the pressure level drops significantly.
As for the temperature regime, here the data are completely ambiguous and are based only on theoretical assumptions. So, at the sole of the mantle, a temperature of 1500-10,000 degrees Celsius is assumed. In general, scientists have suggested that the temperature level in this part of the planet is closer to the melting point.