Science Olympiad Dynamic Planet Practice Test

What is the process by which oceanic lithosphere sinks below continental lithosphere called?

1. Subduction

2. Convergence

3. Divergence

4. Transformation

The correct answer is: Subduction

The process by which oceanic lithosphere sinks below continental lithosphere is called subduction. This occurs at convergent plate boundaries where two tectonic plates move towards each other. Oceanic plates are denser and thinner compared to continental plates, allowing the oceanic lithosphere to be forced down into the mantle beneath the continental lithosphere. As the oceanic plate descends, it can cause a variety of geological phenomena, including the formation of deep ocean trenches and volcanic arcs. Subduction is a crucial aspect of plate tectonics, contributing to the recycling of the Earth's materials and influencing seismic activity. It plays a significant role in shaping the Earth's surface and is responsible for many geological hazards, such as earthquakes and volcanic eruptions. While convergence refers to the movement of tectonic plates toward each other, it is specifically the subduction of the oceanic lithosphere beneath continental lithosphere that dictates the nature of these interactions at such boundaries. Divergence, in contrast, describes the process where tectonic plates move apart, and transformation refers to lateral sliding of plates across each other. These processes do not involve the sinking of one lithosphere beneath another.