The earth’s crust is made out of plate tectonics. Each plate has a defined boundary and direction it moves. The plates in Earth’s crust perform two actions; they submerge under each other or they spread out. The Pacific Plate is the largest plate and it borders around many plates. The Pacific Plate moves northwest. New crust is formed from magma outpours, which are a result of the zones spreading. The tectonic plates created the islands. When the tectonic plates move, it creates the change in geography. Active volcanoes together shape the way islands are build. The magma from the volcano and the deposits from the plate are needed to create the pacific islands structure. The buildup of deposits eventually pushes pass sea level to create the island. The islands that are part of the same volcanic chain will all take over a millions years to rise.…
Firstly, one place where tectonic activity occurs is at oceanic to oceanic constructive plate boundaries. Here two plates diverge or move away from each other, pushed apart by huge convection currents In the earth’s mantle. These convection currents are initiated by heat energy produced from radioactive decay in the earth’s core. As the convection currents move the plates away from each other, there is a weaker zone in the crust and an increase in heat near the surface. The hotter, expanded crust forms a ridge. Magma rises up from the mantle in the gap. The lava cools, solidifies and forms a chain of volcanic mountains thousands of miles long down the middle of the ocean eg. Atlantic. There are transform faults at right angles to the ridge. The movement of these faults causes rift valleys to occur. Examples of these landforms created by constructive plate margins are the Mid Atlantic Ridge (MIR) , and the Great African rift valley (GARV). The MIR is the result of the North American plate and Eurasian plate diverging in the middle of the Atlantic ocean. Here, volcanic islands such as Iceland, the Canary islands and ascension island have been created by the rising magma from the mantle. The GARV is an example of where the crust has dropped down between parallel faults to form rift valleys. As the crust subducts into the mantle it melts causing igneous activity below, magma to rise and therefore volcanoes erupt on the surface as a result. Evidence of this volcanic activity is shown by Mount Kenya and Mount Kilimanjaro.…
The plate tectonics theory was made by a German named Alfred Wegener. He stated that a single continent existed about 300 million years ago named Pangaea and that it split into two continents of Laurasia in the north and Gondwanaland in the south. Today’s continents were formed by further splitting of the two masses.…
Destructive boundaries are between two plates that are colliding. One type is where the oceanic plate collides with a less dense continental plate. As the oceanic plate is subducted into the upper layers of the mantle, various features form. Subduction causes friction to be created by the descending slab of ocean floor, generating a lot of heat leading to a partial melting of a plate. The basaltic magma from this old ocean floor is less dense than the magma of the mantle and rises through fissures and by stoping its way through an overlying rock until it reaches the surface, where it erupts as a volcano. Deep ocean trenches are found along the seaward edge of destructive plate boundaries. They mark where one plate begins to descend under another and reach great depths. On the descending plate there is the Benioff Zone which is the location for earthquakes. Rocks scraped off the descending plate and folding of continental crust help to create young fold mountain chains on the leading edge of the continent for example the Andes on the West Coast of South America.…
The initial theory of continental drift was put forward by a German meteorologist Alfred Wegener in 1915. This theory did not seem credible until it was connected with the plate tectonic theory in the mid 1960's. The Tectonic plate theory had an advantage over previous predictions as it could be supported by observed occurrences. One such thing that supports these two theories is that seen from space the continents look as if they might once have been joined together.…
When two continental plates move towards each other, they collide. This is called a convergent plate movement. One plate will be forced only slightly under the other from pressure, but no subduction will take place. Therefore, the pressing of the plates will uplift the crust by crumpling and form a mountain.…
Plate tectonics is a theory that the earth is split up in to different areas of the world. They glide on the mantle of the earth the plates act like a hard ridged shell (fig 2 plate tectonics) Some of the plate tectonics move very slowly each year for example in Iceland there is a visible line where the plates are moving if the plates merge together they can cause mountains and volcanos. Mountains and volcanoes are formed buy two plates colliding together and one plate gets pushed down into the earth while the other gets pushed up and creates a mountain range or volcanoes.(Figure 2 plate tectonics)…
The Nazca Plate which is an oceanic plate in the west is dragged to move towards the South American Plate which is a continental plate in the east. The force driving the two plates to collide is resulted by converging subcrustal currents of magma in the asthenosphere below the earth crust. Such slow collision of the two plates takes place very slowly over millions of years in earth’s history.…
Continental drift was what cause all the continents to drift together about 200 million years ago forming a super continent that we have named Pangaea. Then around the Jurassic period in time Pangaea broke apart and in this formed two smaller continents.…
The global seismic and volcanic activity is concentrated along the margins of the earth’s plates, which are broken pieces of the crust and are moved by convection currents that are caused by heat rising and falling inside the mantle generated by radioactive decay in the core. This movement of the plates and the Earth’s inner activity is called plate tectonics and can cause seismic and volcanic activity. However, earthquakes and volcanoes also occur within the plates rather than their edges, an example of which is the Hawaiian volcanoes that occur above a stationary hot spot beneath the Pacific plate. In the late 1960s the theory of plate tectonics was developed by Alfred Wegener and provides an explanation for the Earths tectonic behaviour, particularly the global distribution of mountain building, earthquake activity, and volcanism in a series of linear belts. However, before the theory was developed people had noticed that the continents either side of the Atlantic Ocean seemed to nearly fit together. In 1912 Alfred Wegner published the theory of continental drift suggesting that the continents used to be joined together in an ancient supercontinent which he named Pangaea. He then proposed that it later split in to two continents- Laurasia in the north and Gondwanaland in the south, which further split forming our current continents and at some point these land masses had drifted apart to their current positions on the globe.…
The theory of continental drift first came to be in 1915 when Alfred Wegener first proposed his belief that 300 billion years ago there was one single supercontinent, Pangaea. At the time, most did not believe it was true as he had no proof or idea of how the masses of land would move. However, new evidence was put forward over time that fit with Wegener’s beliefs.…
According to the Plate Tectonic theory, the lithosphere breaks up into the tectonic plates. Currently, there are seven or eight major plates in the Earth. Generally, the lithospheric plates remain on the asthenosphere. All the plates move in relation to one another and according to this rule, three plate boundaries are formed. Such as: the collisional or convergent boundaries, spreading center or divergent boundaries and transform or conservative boundaries. All the major activities like the eruption of the volcanoes, earthquakes, oceanic trench and mountain building occur along the plate boundaries.…
Have you ever wondered where mountains come from, why there is a sea floor, island arcs or even volcano and what plate tectonic have to do with this? Well worry no more as all your question on the earth’s surfaced topographic relief elements and plate tectonics are about to be answered. The first question that might come to mind is what is a relief? A relief is a land form that is naturally developed or created on the earth’s surface, and the study of these land forms is called topography as such the term topographic relief is just land forms that are studied. These landforms are able to be studied through theories that were originated by pioneers such as Alfred Wegener, Harry Hess, J. Tuzo Wilson and many others, theses men all contributed to plate tectonics; which is the study of the plates that makeup the lithosphere, their movements and how these movements has influenced changes in the surface’s topography (Strahler, 2011, 389). These plates either sink in to the mantle creating subduction zones which occurs at convergent plate margins or move away from each other causing magma to rise and spread this occurs at divergent plate margins. These plate margins create various relief elements such as volcanoes, Fold Mountains, sea floors and many others. How they do this is not a mystery as at convergent plate margins it’s the rising of magma that creates volcanoes.…
Volcanic mountains are mountains that form when molten rock erupts onto the earth's surface. They can either form on land or in the ocean. The Cascade Range in Washington, Oregon and northern California is composed of volcanic mountains. Some of the largest volcanic mountains are found along divergent boundaries, which form the mid-ocean ridges. The mid-ocean ridges have huge volcanic mountain chains that run through the Atlantic, Pacific and Indian Oceans. The mountains in the mid-ocean ridges can actually grow tall enough to create islands such as Iceland or the Azores.…
* Fold Mountains are mountain ranges that are formed when two of the tectonic plates that make up the Earth's crust push together at their border. The extreme pressure forces the edges of the plates upwards into a series of folds.…