For those people who inattentively listened to the teacher at school, it will be interesting to know that the main element that makes up the earth's crust is oxygen.
Earth's crust, its features
The two main types of the earth's crust are continental and oceanic. From the names it is clear by what principle they are divided. They vary in composition, structure and other characteristics.
The layers of the earth's crust in the oceanic regions are as follows:
- sedimentary, which covers the bottom of the ocean (layer thickness - from several meters to two kilometers);
- basalt, formed as a result of crystallization of magma, which leaves the magma chambers (thickness - from 4 to 10 kilometers);
- gabbro-serpentinite, separating the earth's crust from the mantle (5-6 kilometers).
It is interesting that earlier the oceanic crust was divided only into the first two layers, but after conducting geological research, scientists isolated the third layer.
Layers of the Earth's crust in continental regions:
- sedimentary (thickness - up to 15 kilometers);
- granite (from 15 to 50 kilometers);
- basalt (15-20 kilometers).
The continental crust has a much greater thickness (i.e., thickness) than the oceanic crust, because it rises above sea level, and in mountain regions in general it significantly exceeds the thickness of the oceanic crust.
The chemical composition of the earth's crust
As mentioned above, the main element that makes up the earth's crust is oxygen. Naturally, it is not present in its pure form, but acts as compounds with other chemical elements that make up this composition, and in this form its share is more than 49 percent.
The composition of the earth's crust is called aluminosilicate, according to the compounds of aluminum (the 13th element in the periodic table of chemical elements) and silicon (silicon - in the periodic table with an atomic number of 14) with oxygen. In the oceanic crust, the percentage of SiO 2 is 61.9, while in the continental it is 49.4, and the content of the aluminum compound Al 2 O 3 is almost the same - 15.6% and 16%, respectively. Other elements, such as calcium, magnesium, ferrum, titanium, sodium, potassium, manganese, which also oxidize the main element that makes up the earth's crust, occupy fractions from 0.1 to 5.7 percent.
What knowledge in the study of the earth's crust gives school science geography
The Earth’s crust in the educational process is considered in the context of what planet Earth consists of, that is, we are talking about the central inner ball — the core, the mantle, and, in fact, the earth’s crust, consisting of lithospheric plates moving at a low speed (up to 10 centimeters in year) by mantle. Once a Canadian geophysicist made an interesting comparison. He said that the Earth is similar to an egg, cooked "in a pouch", that is, not hard boiled.
The structure of the earth's crust (grade 7, by the way, examines the topic in more detail and thoroughly than the sixth program) is studied on the basis of textbooks that do not always keep up with new discoveries and changes in the structure of the Earth’s objects. But the basic concepts are introduced quite easily and correctly.
Surprises from the bowels of the Earth
Do not think that since the movement of the layers of the earth's crust is so insignificant - only 10 centimeters a year, then there are no dangers for human life. On the contrary, the activity hidden under the earth’s crust is very active and powerful. We are talking about earthquakes and explosions of volcanoes.
Some sources indicate that about five hundred thousand earthquakes of various capacities occur throughout the world every year. Most activity was seen around the Pacific plate.
What to do with this natural disaster?
An earthquake cannot be prevented. The forces that provoke this disaster are beyond human control, for their source is much deeper than humanity could penetrate. We are just “picking” the upper layer (so far within 13 kilometers), at a time when the deepest recorded location of the earthquake epicenter was 750 kilometers.
But everything was done to anticipate a possible disaster, its strength and place. For this, seismographs are used.
Continuous research makes it possible to compose a picture of seismological activity and take this into account during construction. Engineers, in turn, are working on new designs that can withstand such activity. Constant work is underway to inform the public about how to behave in the event of an earthquake.
The terrible phenomenon that may arise as a result of such a disaster is the tsunami. So, in 2011, huge waves of ocean water devastated the lands of Northeast Japan, as a result of which about 16 thousand people were killed, and more than a million buildings were completely or partially destroyed. Including three reactors at the Fukushima-1 nuclear power plant. Over three hundred thousand people were left without a roof over their heads. The same event affected the Earth's rotation speed, but this is hardly noticeable for humans, since the day has become shorter by only 1.8 microseconds. So, having touched upon the topic of what is the main element that makes up the earth's crust, we turned to the problems that may arise due to the processes hidden by it.