Final answer:
Rocks are older away from ocean trenches due to seafloor spreading and plate movement. The oldest seafloor is found in the Pacific Ocean basin, dating back 180 million years, while the oldest continental rocks are estimated to be around 3.5 billion years old.
Step-by-step explanation:
Oceanic trenches are formed at convergent plate boundaries, where one tectonic plate is forced beneath another. These areas are associated with subduction zones, where oceanic crust is being recycled back into the mantle. As a result, rocks near ocean trenches tend to be younger than rocks found in other areas of the ocean floor.
Seafloor spreading and the movement of tectonic plates cause older rocks to be pushed away from ocean trenches. The youngest rocks are found near the mid-ocean ridges, which are the plates' spreading centers.
Therefore, rocks are older away from ocean trenches. For example, the Pacific Ocean basin has the oldest seafloor, with some areas dating back as far as 180 million years. In comparison, the oldest continental rocks are estimated to be around 3.5 billion years old, which is much older than the oldest seafloor rocks.