original question: Which geographical feature category has the subcategories of [Submarine canyon]?
answer: undersea
answer type: Geographical feature category.
auxiliary information: A submarine canyon is a steep-sided valley cut into the sea floor of the continental slope, sometimes extending well onto the continental shelf and having relief comparable to even the largest of land canyons. About 3% of submarine canyons are joined to shelf valleys that connect with large rivers; the largest canyons incise into the continental shelf but the largest number of canyons terminate on the slope, making so-called ‚Äúblind‚Äù or ‚Äúheadless‚Äù canyons. Canyons cutting the continental slopes have been found at depths greater than 2 km below sea level. Many submarine canyons continue as submarine channels across continental rise areas and may extend seawards for hundreds of kilometres onto the abyssal plain. Ancient examples have been found in rocks dating back to the Neoproterozoic. Turbidites are formed in submarine canyons.
The subcategories of [Submarine canyon] is part of which geographical feature category?