![]() ![]() ![]() ![]() These nodules may provide a significant resource for future mining ventures. Metallic nodules are common in some areas of the plains, with varying concentrations of metals, including manganese, iron, nickel, cobalt and copper. The remainder of the sediment is composed chiefly of pelagic sediments. Much of this sediment is deposited by turbidity currents that have been channelled from the continental margins along submarine canyons down into deeper water. Abyssal plains result from the blanketing of an originally uneven surface of oceanic crust by fine-grained sediments, mainly clay and silt. This is constantly pulled sideways by spreading of the seafloor. Magma rises from above the asthenosphere (a layer of the upper mantle) and as this basaltic material reaches the surface at mid-ocean ridges it forms new oceanic crust. The creation of the abyssal plain is the end result of spreading of the seafloor (plate tectonics) and melting of the lower oceanic crust. They are poorly preserved in the sedimentary record, because they tend to be consumed by the subduction process. In addition to these elements, active oceanic basins (those that are associated with a moving plate tectonic boundary) also typically include an oceanic trench and a subduction zone.Ībyssal plains were not recognized as distinct physiographic features of the sea floor until the late 1940s and, until very recently, none had been studied on a systematic basis. Abyssal plains are key geologic elements of oceanic basins (the other elements being an elevated mid-ocean ridge and flanking abyssal hills). They are among the flattest, smoothest and least explored regions on Earth. Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth’s surface. Diagrammatic cross-section of an oceanic basin, showing the relationship of the abyssal plain to a continental rise and an oceanic trench File:Oceanic divisions.svgĭepiction of the abyssal zone in relation to other major oceanic zonesĪn abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between 30 m. ![]()
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