Talking about the Earth, one of the things that is quite interesting to discuss is the constituent of the Earth itself. Basically, the constituent of the Earth is divided into two main groups, namely biotic and abiotic factors. Interaction of these two factors can then form various reliefs of the Earth surface and influenced by various dynamics of varying atmospheres. (Also read: Natural Phenomena that Occurs in the Troposphere).
It can be said that each surface of this Earth has different constituent characteristics. This then led to various types of zoning in all corners of the Earth. Zoning or division of regions based on natural features is what then turns into a continent with the countries in it. (Also read: 10 Ways to Preserve the Sea and the Beach for the Earth).
If we focus on the relief or the surface of this Earth, then there are various types that we can mention, starting from the mountains, watersheds, forests, deserts, hills, and many other forming factors. In addition, the existence of each relief is one of the factors that influence the distribution of flora and fauna.
This time, we will discuss one of the reliefs of the Earth which is quite important, delta. Many of you may have heard about what a delta is. However, they do not know more about the delta itself. There are some things you should know, like:
Definition of Delta
Derived from the meaning or understanding of the delta itself, we can find 3 notions of the delta which are quite famous, namely:
- Understanding Delta According to Coleman, 1968; Scott & Fischer, 1969:
In this sense, it is said that Delta is deposited which is formed due to the activity of rivers and river mouths. This activity results in the appearance of sedimentation deposits which produce irregular progradation and occur on the coastline.
- Understanding Delta According to Elliot, 1986 in Allen, 1997:
In this sense, it is said that deltas are part of the coast that is more indebted to the sea. This part is formed from the presence of sedimentation deposits of rivers entering the sea, lake, lagoons, and this sedimentation has a volume greater than the ability to redistribute by the existing process.
- Understanding Delta According to Boggs (1987):
Boggs said that the delta is a precipitate formed by the presence of a fluvial sedimentation process entering a calm water area.
From this point of view, we can see that the notion of the delta is a sedimentation deposit caused by particles carried by the river. Sedimentation itself is basically exogenous energy that can form a new face on the surface of this Earth. (Also read: Marine Sediment Rocks: Definition, Types, and Examples).
Types of Delta’s Morphology
Further more, we will discuss the morphology of the delta itself. There are several delta morphology that we can find, such as:
- Delta Plain
This delta region is much closer to the mainland. This area itself is an area of the delta which is dominated by sediments originating from the land rather than from the ocean. This delta plain area will then turn into a swamp area. Usually, this area is more dominated by finer grains of material such as organic shale and coal. The delta plain area is in the river flow distribution area just before entering the sea area. This also includes the brackish area which is the initial meeting of seawater and river water.
- Delta Front
This delta area is one of the delta areas which is quite active in a deposition. Usually, the deposition in this area is dominated by sand. In addition, this area is one of the areas that actively intersects directly or not with other marine activities. The formation of the delta front itself can be said to have a considerable amount of time. Usually, we will find Delta fronts in areas where the entry of river water with sea water. Even so, the bottom line here is that delta fronts are still a part of delta plain.
This prodelta area is the furthest area of a delta. This area can almost be said to jut into the sea area. To be able to find out the prodelta region, it takes several samples from the submarine layers around the delta. This is because the prodelta region is dominated by very fine material.
Types of Delta
According to the type,delta can be divided into 4 main types, namely:
- Delta Lobben: is a delta formation that resembles a bird’s foot. This delta has a fairly fast formation rate. Because the sedimentation process itself is quite fast.
- Blunt Delta: this type of delta has a shape that resembles an arc. Other than that, the formation of this delta will appear unchanged or stagnant.
- Tapered delta: this type of delta has the shape of a cone. Along with its development, the longer it is, the narrower it will be.
- Delta Estuaria: This type of delta is a low part of the river mouth that we often find.
Those are a brief explanation about the delta. Although it is formed from a sedimentation process, each delta will have different characteristics that are quite unique and interesting to observe. Hopefully, this information will be useful for all of you.