Explain why plates move around on Earth’s surface. (
Plates move around on Earth's surface due to the process of plate tectonics. The Earth's lithosphere, which is broken into several large and small plates, rests on the semi-fluid asthenosphere layer below. These plates are constantly in motion, albeit very slowly, with a rate of movement roughly comparable to the growth of human fingernails.
The driving force behind plate movement is convection currents in the Earth's mantle. These convection currents occur due to the transfer of heat from the core to the surface. As the mantle heats up, its material becomes less dense and starts to rise towards the surface. In turn, cooler and denser material sinks downwards, creating a circulation pattern.
This rising and sinking of mantle material causes the overlying tectonic plates to move. Where two plates meet, there are three main types of plate boundaries: convergent, divergent, and transform boundaries.
At convergent boundaries, two plates collide. If one plate is denser than the other, the denser plate typically sinks beneath the lighter plate in a process called subduction. This subduction can give rise to features such as trenches, volcanic arcs, and mountain ranges.
At divergent boundaries, two plates move away from each other. This movement creates a gap, which is filled by upwelling magma from the mantle. The upwelling magma cools and solidifies, creating new oceanic crust. This process, known as seafloor spreading, pushes the two plates apart. Divergent boundaries are responsible for the creation of mid-ocean ridges.
At transform boundaries, two plates slide past each other horizontally. These boundaries often result in earthquakes as the plates are locked together and then suddenly slip past one another.
Overall, the movement of plates on Earth's surface is driven by the convective movement of material within the Earth's mantle. This movement results in the continuous creation, destruction, and rearrangement of Earth's crust, leading to various geological phenomena such as mountains, volcanoes, earthquakes, and oceanic basins.