Accidents and shapes that modify a flat surface make up its relief. It can be depressions or elevations that alter the appearance. Mountains, canyons, mountains and valleys, in this sense, form the relief of our planet.
The Land reliefTherefore, it includes those changes that can be seen on the planet’s surface, either at the surface level or on the seabed. It can be differentiated between emerged relief (which develops above sea level) and the ocean relief (which is submerged).
The notion of continental relief is linked to the forms that exist in the continents (that is, to the emerged surface) and in the submerged area closest to them (known as Continental platform). This definition shows us that the continental relief can also be classified as emerged relief and that is part of what we understand as Land relief.
Because the continents occupy close to the 30% of the Earth, the continental relief develops in that percentage of the planet. It includes all the mountains, plateaus, valleys, depressions, and plains found in the Antarctica, America, Europe, Africa Y Asia.
The continental relief can be understood as the areas of the lithosphere that is not covered by the ocean. From the Pampas plain until the Andes mountains, going through the Alps and the Sahara desert, the continental relief stands out at all points of the planet.
If we analyze the continental relief taking into account its magnitude, we can distinguish between two large groups: the macro-forms and the minors. Let’s see below those corresponding to the first:
* shields and ancient massifs: they were formed in the period Precambrian, the most extensive stage in the history of our planet. These are the oldest landforms, and erosion and internal forces have acted on them with great intensity for a long time, giving them “new life”, restoring their youth;
* sedimentary plains and basins: these landforms are lands that usually do not exceed 200 meters and have few geographical features. In Latin America, sedimentary ones are predominant, that is, those plains that they have been born above large basins on which sediments have been deposited for several hundred years;
* mountain ranges that were recently formed: these are alignments of mountains that have risen in the last million years, a period that for the Earth can be considered “recent”. Some examples of this type of continental relief macroform are the Mountain range of the Andes, the Alpines and the Himalayas. Since they have not suffered erosion for as long as other forms, the mountain ranges formed at this time are the highest in the world.
Among the minor forms of relief are the following:
* alluvial (or river) terraces: they are tables or sedimentary platforms of little extension that were built in a Valley fluvial because of the sediments of the river that remain on the sides of the channel, where its slope (and, therefore, its carrying capacity) decreases;
* dejection cones: they are also known by the name of alluvial fans, and these are formations that resemble terraces formed at the point at which a stream connects with a plain. The sediments carried by the former are deposited as a kind of fan and do not usually form a single channel, but several, and open in the higher floods. intensity;
* overlapping cones: in the Valley of Death, in North America, there is a clear example of dejection cones that have been superimposed. There, various streams converge, which open up when they reach the bottom of the valley, a phenomenon known as “fluvial coalescence.”