Science Olympiad Dynamic Planet Practice Test

What is primarily indicated by the age of rocks collected from mid-ocean ridges?

1. Rocks are older further from the ridges

2. Rocks are chemosynthetically formed

3. Younger rocks lie closer to mid-ocean ridges

4. All rocks in the ocean basin are the same age

The correct answer is: Younger rocks lie closer to mid-ocean ridges

The correct answer is that younger rocks lie closer to mid-ocean ridges. This is a fundamental concept in the study of plate tectonics and oceanography. Mid-ocean ridges are locations where tectonic plates are diverging, leading to the formation of new oceanic crust. As magma from the mantle rises and solidifies at the ridge, it creates new rock. As you move away from the mid-ocean ridge, the rocks become progressively older. This phenomenon occurs due to the continuous process of seafloor spreading, where new crust is generated at the ridge and older crust is pushed away. Age-dating of these rocks shows a clear pattern where the youngest rocks are found directly at the ridge, while older rocks are located further out into the ocean basin, supporting the theory of plate tectonics. Understanding this process helps explain many geological features and processes in ocean basins, including the distribution of age amongst the rocks beneath the ocean.