Tombolo Landforms- Forming the Concept
The term "tombolo" originally comes from a country named Italy. It is applied to one or more than one sand spit that connects an island to the mainland. It is a fairly common feature along “coastlines of submergence” which are in a youthful or early mature stage of development in the present situation. It is necessary for a single tombolo to be associated with a tied island. For example, include the Portland Bill in southern England which is tied by the Chesil Beach to the mainland, as well as Chester, Nova Scotia. Portland Bill island consists of an erosional remnant of the rocks that makes up the mainland. Whereas Chester consists of a drumlin that is partially submerged. Several of the latter types occur also in New England, UK.
Tombolo landform is one or more sandbars or spits which do the work of connecting an island to the mainland. A single tombolo might connect a tied island to the mainland, just like at Marblehead, Massachusetts. Whereas a double tombolo encloses a lagoon which eventually gets filled with sediments and the fine examples of these occur off the coast of Italy.
The shallower waters that can be seen occurring between an island and the mainland are the loci of such features because sandbars form there.
Adam’s Bridge, which connects Sri Lanka (Ceylon) with India across the 33-mile (53-kilometre) wide Palk Strait, was formerly the largest tombolo in the world. This was unfortunately naturally destroyed many thousand years ago by a slight change in mean sea level, and therefore only a chain of sandbanks that seriously hinder navigation exists there today.
The below image explains the tombolo landforms:
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Tombolo Formation
The tombolo formation occurs in a very different way. It is caused by the diffraction of the wave at the ends of an obstacle, which creates a convergence of opposing flows of sediment transport. Depending on the input of sediments as well as on the trends of the sea level, the accumulation of sediments leads to the continuous Programmation of the coastline towards the detached obstacle that is usually an island.
Sediments are sands or gravels. In the backside of the obstacle, a smaller sediment protrusion can also be developed. The ultimate phase of this process is the complete coalescence between these sediment features as well as the blockage of the water body located behind the obstacle that leads to the consequent formation of a connection between the obstacle and also the mainland (the tombolo).
The image explains tombolo formation:
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Tombolo Geography
The Tombolos generally demonstrate the sensitivity of shorelines. A small piece of land, such as on an island, or a beached shipwreck a change might take place depending on the way that waves move. This leads to the different deposition of the sediments. The rise in the sea level may also contribute to the accretion because the material is pushed up with the rising sea levels.
Tombolos are very much more prone to natural fluctuations of profile and area as a result of tidal and weather events than a normal beach is. Due to this susceptibility to weathering because of nature, tombolos are sometimes made more sturdy through the construction of roads or parking lots. The sediments that make up a tombolo are coarser towards the bottom whereas towards the surface it is finer. It is very convenient to see this pattern when the waves are destructive and wash away finer-grained material at the top, which reveals the coarser sands and also cobbles as the base. The below image explains the tombolo geography perfectly.
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Where are Tombolos Found?
Tombolos are one or more than one sandbars or spits that connect an island to the mainland. A single tombolo connects a tied island to the mainland. For example the Marblehead in Massachusetts.
A double tombolo encloses a lagoon that eventually gets filled up with sediments. For example, the coast of Italy.
The world-famous tombolos are Chesil Beach which is located on the southern coast of Dorset, England. This beach connects to the Isle of Portland, which is a 4-mile long, limestone island and it is an inhabited island with a population of around 12,400 people.
What is a Bar Landform?
In physical geography, a bar is considered as a linear shoaling landform feature within a body of water that tends to be long and narrow. It develops where current or the waves promote deposition of particles that results in localized shallowing of the water. Bars might appear in the sea, in a lake, or in a river.
FAQs on Tombolo
1. What is the Difference Between Tombolo and Bar?
Ans: The word tombolo, from the Italian tombolo, is derived from the Latin tumulus, which means 'mound'. The formation of a tombolo occurs when a spit connects the mainland coast to an island. The process of longshore drift occurs and this leads to the movement of the material along the coastline.
The backwash then takes it back out towards the sea at right angles to the coast. The process of Longshore drift causes the development of a bar when the waves that meet at a beach at an angle and backwash perpendicular to the shore that leads to the movement of the sediment on the beach at a zigzag pattern. A spit is a landform that is formed after the deposition on-off coasts.
2. What is a Lagoon?
Ans: Bars have trapped water that leads to the formation of lagoons. The lagoons are likely to remain and fed by the streams that flow into them. Lagoons are generally separated from larger bodies of water by sandbars, barrier reefs, coral reefs, or even by other natural barriers. Lagoon has been derived from the Italian word laguna, which means "pond" or "lake."
The word “lagoon” is sometimes used as a name for a larger region that contains one or more lagoons even after well-defining lagoons geographically. For example, Laguna Madre on Texas Gulf Coast is actually made up of very small bays as well as lagoons, and whereas Laguna Beach in Southern California is actually a beach and not a lagoon.
