The Marianas trench contains Challenger Deep, the deepest point in the ocean floor that we know of today. Challenger Deep is located over 11,000 meters below the ocean surface. What ocean zone would be located just above the floor of Challenger Deep?

Above the floor of challenger deep, the ocean zone located would be the Hadal zone .

Explanation:-

THE CHALLENGER DEEP -  The deepest location in the ocean is the Challenger Deep, at the southern end of the Mariana Trench (sometimes called the Marianas Trench). It is difficult to measure its depth from the surface, but modern estimates vary from 305 meters (less than 1,000 feet). The Challenger Deep 's great depth is due to the successful steepening of the subducting slab along a region of poor link with the overriding plate tearing away from the northern part of the Mariana Trench in the southern part of the Mariana Trench.

THE HADAL ZONE -: The Hadal zone (named in Greek mythology after the domain of Hades, the underworld),, is the ocean's deepest area lying within oceanic trenches. The hadal zone is located at a depth of about 6,000 to 11,000 meters (20,000 to 36,000 feet) and is present in long but narrow V-shaped topographic depressions.

Hence, the answer is Hadal zone ,which is located just above the floor of Challenger Deep.