The Marianas Trench is an example of what?

the mariana trench is an example of a deep ocean canyon and it is formed by the fusion of sub-merging of the Eurasian plate and the Philippine Plate. Not all trenches are as deep as Mariana Islands. The descend part of the Marian is called Challenger Deep and it covers most of the southern part of trench.

The Marinaras Trench is the deepest sea trench on Earth. It is found in the Pacific Ocean, and was formed by the collision of two tectonic plates called the Pacific Plate and the smaller plate, Marinara Plate.