Plate tectonics essay
Assess the strength of the relationship between tectonic processes and major landforms on the earth’s surface.
Tectonic processes have been responsible for the major landforms across the Earth’s surface. These processes are controlled by the convection currents rising from the Earth’s mantle.
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 lava here has a low viscosity, it very hot (1200 C) and has a low silica content.
An example of where
Tectonic processes have been responsible for the major landforms across the Earth’s surface. These processes are controlled by the convection currents rising from the Earth’s mantle.
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 lava here has a low viscosity, it very hot (1200 C) and has a low silica content.
An example of where