- It has a muddy seabed, with scattered abyssal hills that covers an area approximately half the size of Europe's landmass.
- The elements of an active-and growing-oceanic basin include an elevated mid-ocean ridge, flanking abyssal hills leading down to abyssal plains.
- North and south of the FTFZ the ocean floor is relatively smooth with long abyssal hills, probably detachment faults, aligned near-parallel to the ridge axis.
- Xenophyophores are often found in areas of enhanced organic carbon flux, such as beneath productive surface waters, in sub-marine canyons, in settings with sloped topography ( e . g . seamounts, abyssal hills ) and on continental slopes.