PLATE TECTONICS

Plate tectonics theory was accepted globally by scientists during the late 1960s. This theory is a modern upgrade to the theory of continental drift. Plate tectonics is the theory that suggests that the outer layer of the Earth, that is the crust which is also called the lithosphere, are subdivided in various plates which glide above the asthenosphere. The molten nature of the upper layer of mantle allows the lithosphere to glide and subsequently helps in the formation of various terranean structures. This formation gives birth to new landforms with their geological process and consequently its own natural habitat.

Plate tectonics: overview

It was during the period of 1950s to 1970s that the plate tectonic theory was accepted by the scientists over the continental drift theory and was considered a modern upgrade. Over millennia the geographical borders are altered as they submerge, collide and separate from one another, marking retrials of geographical history. In recent times, science has discovered that the geological structure undergoes a process of gradual change and we are able to measure the rise and erosion of mountains, expansion and shrinkage of oceans and the resultant volcanoes and earthquakes.

Plate tectonic theory

According to the theory of plate tectonics, the exterior layer of the crust of earth, which is termed as lithosphere, is separated into several other plates that glide over the asthenosphere, which is a molten surface and is the upper layer of the mantle. This molten surface helps Oceanic and continental plates to either merge together or split apart and then interact with the other plates at their respective boundaries. These boundaries of the tectonic plates are responsible for their respective process of landform formation and geological process. Nicholas van der Elst, a seismologist, has stated that this is a unifying theory of geology.

Tectonic plates: types

The tectonic plates of the lithosphere is an irregular and gigantic plate that is mostly a unified slab of rock that is composed of both the lithosphere of continental and oceanic plates. The crust is further subdivided into seven major and some minor plates. The seven major plates areAfrican plates, Eurasian plates, Antarctic and Pacific plates, India- Australian plates and North American and South American plates. Few of the notable minor plate’s include Arabian, Nazca, and Scotia and Caribbean plates.

Types of tectonic plate boundaries

There are two distinct types of boundaries, divergent and convergent boundaries that are formed as a result of these tectonic plate divisions. The divergent boundaries are responsible for the division of the tectonic plates that forms a narrow rift valley. 

• At this stage, the geysers shoot extremely heated water. At times, magma or molten rocks are spurts forth from the mantle to the outer layer of earth which leads to the formation of basalt which forms a new layer of crust. This process is responsible for the formation of oceanic crusts. 
• Most notably, the mid-oceanic ridge, which ranges 65,000 kilometres in length and 1,500 kilometres in width, is the longest mountain range. 
• At Iceland, the divergence of the Eurasian and North American plates can be observed along with the mid-Atlantic range as the ridge continues to rise above sea level.

At the convergent boundary, the tectonic plates collide with each other. The collision leads to the formation of the deformed landform at the site of the impact that creates mountain ranges due to the upthrust or it might lead to the formation of a deep-sea trench.

• At the site of the converging boundaries, continental boundaries are created and it destroys the oceanic crust which is an aftermath of melting and subduction as a result it turns into magma
• Convergent tectonic plate movement also causes intensive earthquakes and leads to a surge of volcanoes. 
• Himalayas were formed as a result of a convergence of the Eurasian and Indo-Australian continental plates. 

Conclusion

Plate tectonics theory dictates the process of formation of geographic structures and its resultant processes that leads to the formation of the structures of the rocks, mountain ridges, oceanic plates and structures. There are two types of plates that come into existence as a process of convergent and divergent plates that form due to separation or collision of lithospheric boundaries of landforms. One of the most iconic divergent plates can be noticed in Iceland and the convergent resultant can be seen in the Himalayan mountain range. As a result of convergence and divergences volcanoes and earthquakes occur that alter the geographical structures of earth and affect the inhabitant lifeforms.