Science Olympiad Dynamic Planet Practice Test

What is the term for the process by which new oceanic crust is formed at mid-ocean ridges?

1. Subduction process

2. Seafloor spreading

3. Continental drift

4. Thermal convection

The correct answer is: Seafloor spreading

The process by which new oceanic crust is formed at mid-ocean ridges is known as seafloor spreading. This phenomenon occurs when tectonic plates move apart at divergent boundaries, allowing magma from the mantle to rise up and solidify, creating new crust. As the tectonic plates separate, the newly formed crust continually pushes the older crust away from the ridge, effectively widening the ocean basin over time. This process is a fundamental aspect of plate tectonics and is directly observable at mid-ocean ridges, such as the Mid-Atlantic Ridge, where volcanic activity and the formation of new crust are underway. Subduction, continental drift, and thermal convection do not describe this specific formation of oceanic crust. Subduction refers to the process of one tectonic plate being forced beneath another, typically leading to the recycling of oceanic crust rather than its creation. Continental drift pertains to the movement of continents across the Earth's surface over geological time, while thermal convection describes the movement within the mantle that drives plate tectonics, but it is not the direct mechanism for the creation of new oceanic crust itself.