The question of what lava is has been of interest to many scientists for a long time. The composition of this substance, as well as its form, speed of movement, temperature and other aspects have become the subject of a number of studies and scientific papers. This can be explained by the fact that it is its frozen flows that are almost the only source of information regarding the state of the Earth's interior.
General concept
First you need to understand what lava is in the modern sense? Scientists call it material in a molten state, located in the upper part of the mantle. While in the bowels of the earth, the composition of the substance is uniform, but as soon as it approaches the surface, the boiling process begins with the release of gas bubbles. It is they who move the red-hot material towards cracks in the crust. In this case, not all liquid is erupted to the surface. Speaking about what the meaning of the word “lava” is, it should be noted that this concept applies only to the outflowing part of matter.
Basaltic lava
The most common form on our planet is basaltic lava. Most of all geological processes that took place on Earth many thousands of years ago were accompanied by numerous eruptions of this particular type of hot substance. After its solidification, the black rock of the same name was formed. Half of the composition of basaltic lavas is an oxide of aluminum, magnesium, iron and some other metals. Due to them, the melt temperature reaches about 1200 degrees. At the same time, the lava flow moves at a speed of about 2 meters per second, which is comparable to a running person. Studies show that later on in the so-called “hot pursuit” they move much faster. Basaltic lava from the volcano is notable for its small thickness. It flows quite far (up to several tens of kilometers from the crater). It should be noted that this variety is characteristic both for land and for the ocean.
Sour Lava
In the case when the composition of the substance contains 63% or more silica, it is called acid lava. The hot material is very viscous and practically unable to flow. The flow speed often does not even reach a few meters per day. The temperature of the substance is in the range from 800 to 900 degrees. The formation of unusual rocks (ignimbrites, for example) is associated with melts of this kind. If acidic lava is very saturated with gas, it boils and becomes mobile. After ejection from the crater, it quickly flows back into the resulting hollow (caldera). The consequence of this is the appearance of pumice - an ultralight material whose density is less than that of water.
Carbon lava
Speaking of what lava is, many scientists still cannot determine the principle of formation of its carbonate variety. The composition of this substance includes potassium and sodium carbonates . It is erupted by only one volcano on the planet - Aldoinho-Lengai, which is located in northern Tanzania. Carbonate lava is the most liquid and coldest of all existing species. Its temperature is approximately 510 degrees, and it moves along the slopes at the same speed as water. Initially, the substance has a dark brown or black color, but after a few hours of being outside it becomes lighter, and after a few months it completely turns white.
conclusions
To summarize, attention should be paid to the fact that one of the most acute geological problems is associated with lava. It lies in the fact that this substance heats the bowels of the earth. The foci of hot material rise to the earth's surface, after which they melt it and form volcanoes. Even the leading world scientists cannot give a clear answer to the question of what lava is. Along with this, it can be asserted for sure that it is only a tiny part of the global process, the driving force of which is hidden very deep underground.