Diagrammatic cross-section of an ocean basin, showing the various geographic features.

Hydrologically, an oceanic basin may be anywhere on Earth that is covered by seawater, but geologically ocean basins are large geologic basins that are below sea level. Geologically, there are other undersea geomorphological features such as the continental shelves, the deep ocean trenches, and the undersea mountain ranges (for example, the mid-Atlantic ridge) which are not considered to be part of the ocean basins; while hydrologically, oceanic basins include the flanking continental shelves and shallow, epeiric seas. Image File history File links Size of this preview: 800 × 548 pixelsFull resolution (1001 × 686 pixel, file size: 68 KB, MIME type: image/png) Diagram representing oceanic basin, displaying various features. ... Image File history File links Size of this preview: 800 × 548 pixelsFull resolution (1001 × 686 pixel, file size: 68 KB, MIME type: image/png) Diagram representing oceanic basin, displaying various features. ... A basin is the inverse of a dome: a symmetrically-dipping syncline that appears on a geologic map as roughly circular or elliptical, with concentric layers. ... Surface of the Earth Geomorphology is the study of landforms, including their origin and evolution, and the processes that shape them. ...  Sediment  Rock  Mantle  The global continental shelf, highlighted in cyan The continental shelf is the extended perimeter of each continent, which is covered during interglacial periods such as the current epoch by relatively shallow seas (known as shelf seas) and gulfs. ... The oceanic trenches are hemispheric-scale long but narrow topographic depressions of the sea floor. ... Courtesy USGS The ridge was central in the breakup of Pangaea that began some 180 million years ago. ...

Some consider the oceanic basins to be the complement to the continents, with erosion dominating the latter, and the sediments so derived ending up in the ocean basins. Others regard the ocean basins more as basaltic plains, than as sedimentary depositories, since most sedimentation occurs on the continental shelves and not in the geologically defined ocean basins.

Hydrologically some geologic basins are both above and below sea level, such as the Maracaibo Basin in Venezuela, although geologically it is not considered an oceanic basin because it is on the continental shelf and underlain by continental crust. A basin is the inverse of a dome: a symmetrically-dipping syncline that appears on a geologic map as roughly circular or elliptical, with concentric layers. ... The Maracaibo Basin in Western Venezuela is a prolific, oil-producing sedimentary basin. ...

Earth is the only planet with bimodal hypsography, reflecting the different kinds of crust, oceanic crust and continental crust. Oceans cover 70% of the Earth's surface. Because oceans lie lower than continents, the former serve as basins that collect sediment eroded from the continents, known as clastic sediments, as well as precipitation sediments. Ocean basins also serve as repositories for the skeletons of carbonate- and silica-secreting organisms such as coral reefs, diatoms, radiolarians, and foraminifera. This article needs to be wikified. ... Age of oceanic crust Oceanic crust is the part of Earths lithosphere which underlies the ocean basins. ... The thickness of the Earths crust (km). ... The term sedimentary basin is used to refer to any geographical feature exhibiting subsidence and consequent infilling by sedimentation. ... In geology, the term clastic refers to sediments formed from fragments of pre-existing rock. ... Part of a coral reef. ... Diatoms are the most common of the eukaryotic algae. ... Classes Polycystinea Acantharea Sticholonchea Radiolarians (also radiolaria) are amoeboid protozoa that produce intricate mineral skeletons, typically with a central capsule dividing the cell into inner and outer portions, called endoplasm and ectoplasm. ... Orders Allogromiida Carterinida Fusulinida - extinct Globigerinida Involutinida - extinct Lagenida Miliolida Robertinida Rotaliida Silicoloculinida Spirillinida Textulariida incertae sedis    Xenophyophorea    Reticulomyxa The Foraminifera, or forams for short, are a large group of amoeboid protists with reticulating pseudopods, fine strands that branch and merge to form a dynamic net. ...

Geologically, oceanic basins may be actively changing size or may be inactive, depending on whether there is a moving plate tectonic boundary associated with it. The elements of an active - and growing - oceanic basin include an elevated mid-ocean ridge, flanking abyssal hills leading down to abyssal plains. The elements of an active oceanic basin often include the oceanic trench associated with a subduction zone. The tectonic plates of the world were mapped in the second half of the 20th century. ... A mid-ocean ridge or mid-oceanic ridge is an underwater mountain range, formed by plate tectonics. ... Abyssal plains are flat or very gently sloping areas of the deep ocean basin floor. ... The oceanic trenches are hemispheric-scale long but narrow topographic depressions of the sea floor. ... Categories: Geology stubs | Plate tectonics ...

The Atlantic ocean and the Arctic ocean are a good examples of active, growing oceanic basins, whereas the Mediterranean Sea is shrinking. The Pacific Ocean is also an active, shrinking oceanic basin, even though it has both spreading ridge and oceanic trenches. Perhaps the best example of an inactive oceanic basin is the Gulf of Mexico, which formed in Jurassic times and has been doing nothing but collecting sediments since then. The Sea of Japan and Bering Sea are also good examples of inactive oceanic basins. Composite satellite image of the Mediterranean Sea. ... Gulf of Mexico in 3D perspective. ... The Jurassic Period is a major unit of the geologic timescale that extends from about 199. ... The Sea of Japan, also known as the East Sea (see naming dispute), is a marginal sea of the western Pacific Ocean, bordered by Japan, Korea and Russia. ... Satellite photo of the Bering Sea Bering Sea and the North Pacific Ocean Bearing Sea with Kamchatka Peninsula and Alaska The Bering (or Imarpik) Sea is a body of water north of, and separated from, the north Pacific Ocean by the Alaska Peninsula and Aleutian Islands. ...

See also

• List of Oceanic basins