An ocean basin is a large geologic basin below sea level that is covered by seawater. It is a vast submarine region that collectively covers nearly three- quarters of Earth's surface and contains almost 97% of all water on the planet. Ocean basins are formed geologically of oceanic (basalt) crust, in contrast to continental (granite) crust that forms the Earth's major land masses
. They have an average depth of almost 4 km and contain various features such as ocean ridges, deep-sea trenches, fracture zones, aseismic ridges, abyssal hills, seamounts, and guyots
. The ocean basins are transient features over geologic time, changing shape and depth due to the process of plate tectonics
