With reference to plate tectonic boundaries and subduction zone morphology, which of the following tectonic settings is responsible for creating the deepest oceanic trenches, such as the Mariana Trench and the Tonga Trench?

💡 Solution & Explanation

Deepest oceanic trenches form at oceanic-oceanic convergent boundaries where the older, denser subducting slab plunges steeply into the mantle, exemplified by the Mariana and Tonga trenches. Oceanic-continental convergence creates mountain chains like the Andes accompanied by deep trenches offshore. Divergent boundaries form rift valleys and constructive crustal ridges. Transform faults accommodate lateral motion without deep trench development.