Studying geography and topography, we are faced with such a concept as terrain. What is this term and what is it used for? In this article, we will understand the meaning of this word, find out what types and forms of reliefs are, and much more.
Relief concept
So what does this term mean? The relief is a set of irregularities on the surface of our planet, which are composed of elementary forms. There is even a separate science that studies its origin, development history, dynamics and internal structure. It's called geomorphology. The relief consists of separate forms, that is, natural natural bodies, representing its individual parts and having their own sizes.
Variety of shapes
According to the morphological classification principle, these natural bodies can be either positive or negative. The first of them rise above the horizon line, representing an uplift of the surface. An example is a hillock, a hill, a plateau, a mountain, and so on. The latter, respectively, form a decrease relative to the linehorizon. These can be valleys, beams, depressions, ravines, etc. As mentioned above, the relief form is composed of individual elements: surfaces (faces), points, lines (ribs), corners. According to the degree of complexity, complex and simple natural bodies are distinguished. Simple forms include mounds, hollows, hollows, etc. They are separate morphological elements, the combination of which forms a form. An example is a hillock. It is divided into such parts: sole, slope, top. A complex form consists of a number of simple ones. For example, the valley. It includes the channel, floodplain, slopes and more.
According to the degree of slope, sub-horizontal surfaces (less than 20 degrees), inclined and slopes (more than 20 degrees) are distinguished. They can have a different shape - straight, convex, concave or stepped. According to the degree of strike, they are usually divided into closed and open.
Types of reliefs
The combination of elementary forms that have a similar origin and extend over a certain space, sets the type of relief. In large areas of our planet, it is possible to combine several separate species on the basis of a similar origin or difference. In such cases, it is customary to speak of groups of relief types. When the association is made on the basis of their formation, then one speaks of the genetic types of elementary forms. The most common types of land relief are flat and mountainous. In terms of height, the former are usually divided into depressions, uplands, lowlands, plateaus and plateaus. Among the second arehighest, high, medium and low.
Flat terrain
This is an area that is characterized by insignificant (up to 200 meters) relative elevations, as well as a relatively small steepness of slopes (up to 5 degrees). The absolute heights here are small (only up to 500 meters). These areas of the earth's surface (land, the bottom of the seas and oceans), depending on the absolute height, are low (up to 200 meters), elevated (200-500 meters), upland or high (over 500 meters). The relief of the plains depends primarily on the degree of ruggedness and soil and vegetation cover. It can be loamy, clayey, peaty, sandy loamy soils. They can be cut by riverbeds, gullies and ravines.
Hilly terrain
This is a terrain with an undulating nature of the earth's surface, forming irregularities with absolute heights up to 500 meters, relative elevations up to 200 meters and a steepness of not more than 5 degrees. The hills are often made of hard rocks, and the slopes and peaks are covered with a thick layer of loose rock. The lowlands between them are flat, wide or closed basins.
Hills
Mountain relief is an area that represents the surface of the planet, significantly elevated relative to the surrounding area. It is characterized by absolute heights of 500 meters. Such a territory is distinguished by a diverse and complex relief, as well as specific natural and weather conditions. The main forms are mountain ranges withcharacteristic steep slopes, which often turn into cliffs and rocks, as well as gorges and hollows located between the ridges. The mountainous areas of the earth's surface are significantly elevated above the level of the ocean, while they have a common base, which rises above the adjacent plains. They consist of many negative and positive landforms. According to the level of height, they are usually divided into low mountains (up to 800 meters), middle mountains (800-2000 meters) and high mountains (from 2000 meters).
Shaping landforms
The age of elementary forms of the earth's surface can be relative and absolute. The first sets the formation of relief relative to some other surface (earlier or later). The second is determined using the geochronological scale. The relief is formed due to the constant interaction of exogenous and endogenous forces. So, endogenous processes are responsible for the formation of the main features of elementary forms, while exogenous, on the contrary, tend to equalize them. In relief formation, the main sources are the energy of the Earth and the Sun, and one should not forget about the influence of space. The formation of the earth's surface occurs under the influence of gravity. The main source of endogenous processes can be called the thermal energy of the planet, which is associated with radioactive decay occurring in its mantle. Thus, under the influence of these forces, the continental and oceanic crust was formed. Endogenous processes cause the formation of faults, folds, the movement of the lithosphere, volcanism and earthquakes.
Geological observations
Scientists-geomorphologists study the shape of the surface of our planet. Their main task is to study the geological structure and terrain of specific countries, continents, planets. When compiling the characteristics of a particular area, the observer is obliged to determine what caused the shape of the surface in front of him, to understand its origin. Of course, it will be difficult for a young geographer to understand these issues on his own, so it is better to turn to books or a teacher for help. Compiling a description of the relief, a group of geomorphologists must cross the study area. If you want to make a map only along the route of movement, then you should maximize the observation band. And in the process of research, periodically move away from the main path to the sides. This is especially important for poorly visible areas, where forests or hills obstruct the view.
Mapping
When recording information of a general nature (hilly, mountainous, rugged terrain, etc.), it is also necessary to map and describe separately each relief element - a steep slope, a ravine, a ledge, a river valley, etc. To determine the dimensions - depth, width, height, angles of inclination - is often necessary, as they say, by eye. Due to the fact that the relief depends on the geological structure of the area, when making observations, it is necessary to describe the geological structure, as well as the composition of the rocks that make up the studied surfaces, and not just their appearance. It is necessary to mark sinkholes, landslides, caves, etc. in detail. In addition to the description, schematic sketches of the study area should also be carried out.
By this principle, you can explore the area near which your home is located, or you can describe the relief of the continents. The methodology is the same, only the scales are different, and it will take much more time to study the continent in detail. For example, in order to describe the relief of South America, it will be necessary to create many research groups, and even then it will take more than one year. After all, the mentioned mainland is characterized by an abundance of mountains stretching along the entire continent, Amazonian virgin forests, Argentinean pampas, etc., which creates additional difficulties.
Note to young geomorphologist
When compiling a relief map of the area, it is recommended to ask local residents where you can observe the places where rock layers and groundwater come out. These data should be entered on the map of the area and described in detail and sketched. On the plains, rock is most often exposed in places where rivers or ravines have cut through the surface and formed coastal cliffs. Also, these layers can be observed in quarries or where a highway or railway passes through a cut-out recess. The young geologist will have to consider and describe each layer of the rock, it is necessary to start from the bottom. Using a tape measure, you can make the necessary measurements, which should also be entered in the field book. The description should indicate the dimensions and characteristics of each layer, their serial number and exact location.
