Beach or mountain? It is probably the question that rings the most in our heads when we look for a destination to take vacations. The land surface is not homogeneous and the diversity of landscapes that exist on planet Earth is determined by the relief.
What is relief
To begin with, geography is the science that studies relief, which is defined as the set of forms that the earth’s surface presents . In particular, orography is a branch of physical geography dedicated to the study, description and representation of the terrestrial relief.
What is curious about the relief is that the diversity of forms that the earth’s surface presents, as we know it today, is the result of a set of processes that took place over millions of years and that continue to occur today. Next we will tell you about the highlighting processes .
Internal relief formation processes
First we must know that the interior of the Earth is made up of layers of rocks with different compositions and densities, which cause movements in the most superficial layer of the Earth, called the earth’s crust or earth’s surface. These movements caused the Earth’s crust to fragment into what we now know as plate tectonics. These plates have been moving for millions of years, some have separated, while others have joined, giving rise to continents, islands, mountain ranges and volcanoes. The truth is that tectonic plates are in constant motion and, depending on the magnitude of their movements, earthquakes and tsunamis can occur .
External relief formation processes
This process is caused by the joint action of biological, climatic, chemical and physical processes, which act to disintegrate the rocks on the earth’s surface. Let’s see in detail what happens:
- Weathering, here the rock is fragmented and disintegrated by the action of temperature, water or even the roots of plants. The dissolution of rock minerals can also occur when the oxygen in the water comes into contact with the minerals.
- Erosion, through which the dragging, transport and accumulation of rocky materials occurs in lower areas of relief. Erosion can be caused by wind, water, or human action.
In particular, the coastal relief is an exemplary case of external relief formation processes: its development is mainly due to the action of the sea on the continent, both by the erosion caused on the coast and by the sediments that it carries towards it.
What is the continental relief? This typology of reliefs is also known as terrestrial relief or, emerged lands or emerged relief , because their formations are above sea level. In this section we will describe the different types of land relief .
They constitute the areas of highest elevation. Its surface is heterogeneous with extremely marked inequalities. When the mountains are aligned, it is called a mountain range. Several chains form what we know as a mountain range. The depressions that separate two mountain ranges are called valleys. In contrast, those mountains that are low in height are called hills or mountain ranges.
They are high lands but with flat peaks whose height can exceed 200 meters above sea level. Like mountains, plateaus can be separated by valleys. They are often referred to as the highlands or highlands.
They are extensions of flat land with slight elevations. The plains are located at altitudes less than 200 meters above sea level. In general, the plains are a type of land relief that presents a wide extension. In addition, these extensive flat land areas are often crossed by rivers and streams.
As in the previous section, the oceanic or underwater relief also has another name: submerged relief . It refers to the fact that its formations are below sea level. Here we will teach you the main underwater landforms .
It is the area closest to the coast and can reach 200 meters deep. It is dominated by sand sedimentation and on some continental shelves there are large deposits of minerals and oil. It has the particularity that it is the only area of the ocean where sunlight penetrates, which allows the existence of a wide variety of marine plant and animal species.
Another example of underwater relief is the continental slope. It is a steep decline that occurs where the continental shelf ends. Some scientists describe it as a wall that reaches 2,000 – 3,000 meters deep. The continental slope is a zone of precipitation of sediments, which then settle to the bottom forming layers or strata.
It is also called the ocean basin and it is the least studied underwater relief due to the difficulty represented by its depth. However, the use of radars and unmanned submarines have made it possible to demonstrate that the abyssal plain presents a relief similar to the continental relief and, therefore, is made up of huge extensions of plains, underwater mountain ranges, hills and volcanoes.