Science Olympiad Dynamic Planet Practice Test

What process is described by the term "ridge push"?

1. The force exerted by a sinking cold plate

2. The expansion of rocks at mid-ocean ridges

3. The pulling of plates into a trench

4. The movement of plates toward each other

The correct answer is: The expansion of rocks at mid-ocean ridges

Ridge push refers specifically to the tectonic process that occurs at mid-ocean ridges, where new oceanic crust is formed by upwelling magma. As magma rises and solidifies, it creates young, hot, and less dense rock, which is elevated compared to the surrounding older, cooler oceanic crust. This topographic elevation results in a gravitational force that pushes the older plates away from the ridge and causes them to move laterally. Choosing the answer related to the expansion of rocks at mid-ocean ridges accurately aligns with this definition, as this process initiates the ridge push mechanism. Additionally, the term captures the essence of how the geological activity at these ridges contributes to plate tectonics through the formation and movement of the crust.