Science Olympiad Dynamic Planet Practice Test

Which geological event typically occurs during the contraction of an ocean basin?

1. Continental collision

2. Oceanic trench formation

3. Mountain uplift

4. Subducted material recycling

The correct answer is: Continental collision

During the contraction of an ocean basin, the geological event that typically occurs is oceanic trench formation. When an ocean basin begins to contract, it indicates a process called subduction, where one tectonic plate is being forced under another. This generally leads to the formation of oceanic trenches, which are deep, narrow depressions in the ocean floor. Oceanic trenches form at convergent boundaries, where an oceanic plate collides with either another oceanic plate or a continental plate. As the denser oceanic plate is subducted, it creates a trench at the boundary where the two plates meet. This process is significant in the recycling of materials within the Earth's lithosphere and contributes to various geological phenomena including earthquakes and the creation of volcanoes. In contrast, continental collision typically results in mountain uplift, which is associated with the collision of two continental plates rather than the contraction of an ocean basin. Subducted material recycling refers to the processes occurring as a result of subduction, but it is the trench formation that is directly linked to the contraction of an ocean basin. Mountain uplift is related to continental plates, not the oceanic processes linked to basin contraction.