Abyssal hills as a genetic type of the World Ocean floor topography

Abstract

Abyssal hills cover about 140 mln. sq. km of the ocean floor and represent the most widely spread relief of the Earth surface. They have not been observed only on flat abyssal plains and on sloping plains near the continental rise; here they are buried under sediments and can be found by means of seismic-acoustic sounding. In some places (such as rift zones of mid-oceanic ridges, aseismic rises on the ocean floor and transform fault zones) the abyssal hills were reworked later by tectonics. Bathymetrieal charts of some proving grounds reveal relicts of this type of relief. The abyssal hills seem to have been far more widespread at the ocean floor in the past, their formation preceded this of the flat and sloping abyssal plains.