The relief of our planet is striking in its diversity and unshakable grandeur. Wide plains, deep river valleys and pointed spiers of the highest peaks - all this, it would seem, has adorned and will adorn our world forever. But this is not so. In fact, the terrain is changing.
But several thousand years are not enough to notice these changes. What can we say about the life of an ordinary person. Earth's surface development is a complex and multifaceted process that has been going on for several billion years. So why and how does the earth's relief change over time? And what underlies these changes?
The relief is ...
This scientific term comes from the Latin word relevo, which means "lift up." In geomorphology, it means the totality of all existing irregularities of the earth's surface.
Three key elements of the relief are distinguished: a point (for example, a mountain peak), a line (for example, a watershed), and a surface (for example, a plateau). This gradation is very similar to highlighting the main figures in geometry.
The relief may be different: mountainous, flat or hilly. It is represented by the most diverse forms, which can differ from each other not only in their appearance, but also in origin, age. In the geographic envelope of our planet, terrain plays an extremely important role. First of all, it is the basis of any natural-territorial complex, like the foundation of a residential building. In addition, he takes a direct part in the redistribution of moisture on the Earth's surface, and also participates in the formation of climate.
How does the terrain change? And what are its forms known to modern scientists? This will be discussed later.
Terrain: main forms and age of relief forms
The shape of the relief is the fundamental unit in geomorphological science. In simple words, this is a specific unevenness of the earth's surface, which can be simple or complex, positive or negative, convex or concave.
The main forms of the earth's relief include the mountain, hollow, hollow, ridge, saddle, ravine, canyon, plateau, valley, and others. According to their genesis (origin), they can be tectonic, erosive, aeolian, karst, anthropogenic, etc. Planetary, mega-, macro-, meso-, micro- and nanoforms of the relief can be distinguished by scale. The planetary (largest) include continents and the ocean bed, geosynclines and mid-ocean ridges.
One of the main tasks of geomorphologists is to determine the age of various relief forms. Moreover, this age can be both absolute and relative. In the first case, it is determined using a special geochronological scale. In the second case, it is established relative to the age of some other surface (the words “younger” or “ancient” are appropriate here).
The well-known relief researcher V. Davis compared the process of its formation with human life. Accordingly, he identified four stages of development of any form of relief:
- childhood;
- youth;
- maturity;
- decrepitude.
How and why does the earth's relief change over time?
In our world, nothing is eternal or static. Similarly, the terrain of the Earth changes over time. It’s almost impossible to notice these changes, because they last hundreds of thousands of years. True, they are manifested in earthquakes, volcanic activity and other earthly phenomena, which we used to call cataclysms.
The main root causes of relief formation (as, indeed, of any other processes on our planet) are the energy of the Sun, Earth, and also space. The change in the Earth's relief is ongoing. And at the heart of any such changes are only two processes: denudation and accumulation. These processes are very closely interconnected, like the well-known principle of "yin-yang" in ancient Chinese philosophy.
Accumulation is the process of accumulation of loose geological material on land or at the bottom of water bodies. Denudation, in turn, is the process of destruction and transfer of destroyed rock fragments to other parts of the earth's surface. And if accumulation seeks to accumulate geological material, then denudation tries to destroy it.
The main factors of relief
The Earth's surface pattern is formed due to the constant interaction of the endogenous (internal) and exogenous (external) forces of the Earth. If we compare the process of relief formation with the construction of the building, then endogenous forces can be called "builders", and exogenous forces - "sculptors" of the earth's relief.
The internal (endogenous) forces of the Earth include volcanism, earthquakes and movements of the earth's crust. To external (exogenous) - the work of wind, flowing water, glaciers, etc. The last forces are engaged in a peculiar design of relief forms, sometimes giving them bizarre outlines.
In general, geomorphologists identify only four relief factors:
- Earth’s internal energy;
- worldwide gravity;
- solar power;
- space energy.