An integral part of the mountain landscape is the valley. This is a special form of relief, which is an elongated depression. It is formed more often from the erosive action of flowing water, and also due to some features in the geological structure of the earth's crust.
What does the word "valley" mean
All sorts of gullies, ravines, gullies caused by intermittent streams are the rudimentary forms of valleys. As a result of washing away the soil by river water, lowlands appear along the banks, which, connecting with each other, can form entire systems.
Their relief is unstable and can change depending on the direction of river flows. A mountain or river valley is part of a complex, branched landscape system. It consists of several elements:
- Slopes are areas of the surface that limit the valley from the sides. They differ in height and, in addition, can have the same or different steepness (when one coast is gentle, and the other is steeper).
- The bottom (bed) is the flattest and lowest part of the valley.
- Sole - the place where they connectbottom and slopes.
- Brovka - the line of contact of the slopes with the surface of the surrounding area.
- Terraces. These are small leveled horizontal platforms located at different heights from the bottom of the valley.
Variety of valleys
Geologists divide all valleys into mountainous and flat. They are formed, according to the name, in a certain area. Mountain valleys are landforms characterized by considerable depth and uneven steep slopes.
The flat ones are wider, with less pronounced depth and with gentle, even slopes, much inferior to the width. The main element is the wide bottom of the cut. The mouth of the valley is often a bay into which the river flows.
Depending on the location of the valley, the meaning of this word is interpreted in different sources. In some, a "valley" is an elongated depression between mountains or hills, while in others, a space below the surrounding area, usually located along a river.
River Valley
Formed as a result of exposure to flowing water. A river valley is an elongated lowland on the land surface, which extends from its source to its mouth. From its appearance, experienced geographers can easily determine the age and stage of development, as well as the geological structure of the area, the movements of the earth's crust in the river basin, learn about the forces of weathering, and much more.
The river valley is a branched isolated system that contrasts sharply with the surrounding landscape. Changerthe direction of the river flow often results in the volatility and remodeling of the valleys, which are periodically rejuvenated. Their hydrological features have no analogues among other types of landscapes. This applies to seasonal floods and rain floods. Spills occur synchronously along the entire profile of the valley.
Slopes of river valleys are usually covered with forest, and floodplains are used for hay land, sowing crops, and settlements are located in the safest places from erosion in these areas.
At large rivers, the floodplain can occupy an area from 15 to 30 km wide. It is low, flooded annually, and high, which goes under water only during severe floods.
The terraces that the river valley has are peculiar notches that can tell a lot about the history of the river. Bedrock lies at their base, and the surface is covered with river sediments. On such terraces, you can find various deposits of former swamps and lakes, the remains of plants and animals that existed a long time ago.
Gorges and valleys are the components of the mountain landscape. They are characterized by steep slopes and rapids. The river cuts through the rock with a powerful stream, forming gorges and canyons with almost steep slopes, where there are no terraces.
The profile of young valleys has sections where rivers are rapidly rushing along the rapids. Over time, under the influence of the flow, the place is leveled. The smooth profile that the valley acquires is a sign of its maturity.
River valley shapes
Many factors influence the formation of the valley. Among them are tectonic processes that determine the direction, rocks, soil sliding and washing away by precipitation. All this contributes to the creation of various forms of river valleys.
Gorges, or gorges, are formed due to deep erosion and are distributed mainly in high mountain areas. Their steep slopes are made up of strong rocks. The bottom in its entire width occupies the riverbed.
Canyons are narrow valleys that form in areas where layers of varying strength occur. The deepest canyon on the Colorado River (in the USA) is considered to be up to 2 km deep.
In the floodplain valleys, the riverbed occupies only a small part. They are characteristic of the plains. The entire valley, together with terraces, can be up to 100 kilometers or more wide. On these plots crops are grown and cattle graze. Not without reason in many encyclopedic sources the word "valley" is interpreted as "fertility", "life", "cultivation".
