Plains of our planet
Plains are areas of the earth’s surface, with a slope of no more than 5 °, and oscillations of heights of no more than 200 meters. This means that the plains do not necessarily have to be even areas of land, as many people think. They can have both flat relief and hilly. And they can be located not only on land, but also on the ocean floor (deep-water plains), on the shelf (shelf), and at the foot of the continents (sloping).
The formation of plains
There are three different ways of forming smooth patches of the earth’s surface. In the first case, the plains formed on platforms, for what they are called platform. In the second case, the plains appeared in the mountains, as a result of the destruction of the latter. They call them the basement plains. In the latter case, the plains formed due to the accumulation of material, they are called accumulative.
Most plains of the world (about 2/3) are platform, sometimes they are also called stratum. They are composed of large layers of sedimentary cover (mostly sedimentary rocks, not metamorphic).
Basement plains are called precisely because the basement is called the foot of something, including the base of the mountain. Although often they are also called denudation (denudation – destruction of the mountain). In general, from the names itself becomes more or less understandable, how such plains were formed.
Under the influence of various natural factors (precipitation, wind, and the like), some mountains gradually collapsed. After that, the residues resulting from the denudation were driven (mainly by streams of water).
As a rule, the plains formed in this way are hilly. Since, though the territory is smooth with time, this is far from ideal. Well, of course, almost always they consist of solid rocks.
Accumulative plains were formed as a result of filling with sedimentary rocks of different cavities and cracks of the earth’s surface. But this did not always happen evenly, therefore their relief is very diverse.
Types of plains
Depending on the absolute heights on which flat planets are located, they are divided into 3 types:
Lowlands, or lowland plains. They are located at an altitude of not more than 200 meters above sea level.
Hills, or elevated plains. They have an absolute height of 200 to 500 meters. In the event that the relief of the hill is flat (well or only slightly wavy), it is called a plateau.
Plateau, or high plains. They have a height of more than 500 meters above sea level.
Plains are the most common form of surface relief on our planet. They occupy about 2/3 of the land area. Most of the planet’s population lives on them, because they have beautiful conditions for life.