The theory of plate tectonics (developed between 1950 and 1970) is the update of the theory of continental drift, an idea that claimed that the Earth’s continents moved across the planet with the passage of time. Although the geophysicist who proposed this hypothesis, Alfred Wegener, did not understand how the continents moved around the planet, researchers have found the solution.
Plate tectonics theory
This unifying theory explains that the outer layer of the Earth is divided into plates that slide over the mantle of the Earth. The outer layer of the Earth, which includes the crust and the upper mantle, is called the lithosphere and is approximately 100 kilometers thick, according to the Encyclopedia Britannica.
Beneath the lithosphere is the asthenosphere , a layer that remains malleable due to heat deep in the Earth. In addition, it also lubricates the underside of the Earth’s tectonic plates, which helps the lithosphere to move.
How does it work?
Because of the poor thermal conductivity of the crust, heat generated on Earth accumulates under the crust and melts the mantle, causing thermal convection in the mantle. That is, hot material near the Earth’s core rises while cooler rocks in the mantle sink.
For this reason, scientists consider that the earth’s crust is fragmented into tectonic plates, which move thanks to convection currents. Also, geologists refer to the places where the segments meet and divide as plate boundaries. There are three different ways that plate boundaries meet, each triggering a unique geological feature.
Convergent boundaries occur when plates collide with each other. When this happens, the earth’s crust crumbles and bends into mountain ranges, as happened, for example, in India or Asia about 55 million years ago to create the Himalayas.
However, converging plates do not always collide upward. An oceanic plate can collide with a continental plate, in which case it dips below the other plate. Later, it descends into the Earth’s mantle and melts into the hot magma of the mantle, until it becomes a volcanic eruption. These types of collisions can also cause undersea volcanoes.
On the other hand, the divergent limits are the tectonic limits where the plates separate. This movement creates giant valleys in the land. In the ocean, on the other hand, this same process gives rise to mid-ocean ridges. Finally, transforming boundaries occur when plates move laterally. In addition, they function as geological faults and often trigger many earthquakes.
