Search results
Results from the WOW.Com Content Network
The continental shelf is the relatively shallow water area found in proximity to continents; it is the portion of the continental margin that transitions from the shore out towards to ocean. Continental shelves are believed to make up 7% of the sea floor. [3] The width of continental shelves worldwide varies in the range of 0.03–1500 km. [4]
The location where two plates meet is called a plate boundary. Plate boundaries are where geological events occur, such as earthquakes and the creation of topographic features such as mountains, volcanoes, mid-ocean ridges, and oceanic trenches.
Map showing Earth's principal tectonic plates and their boundaries in detail. These plates comprise the bulk of the continents and the Pacific Ocean.For purposes of this list, a major plate is any plate with an area greater than 20 million km 2 (7.7 million sq mi)
Geologically, an ocean is an area of oceanic crust covered by water. Oceanic crust is the thin layer of solidified volcanic basalt that covers the Earth's mantle. Continental crust is thicker but less dense. From this perspective, the Earth has three oceans: the World Ocean, the Caspian Sea, [citation needed] and the Black Sea.
The overall shape of ridges results from Pratt isostasy: close to the ridge axis, there is a hot, low-density mantle supporting the oceanic crust. As the oceanic plate cools, away from the ridge axis, the oceanic mantle lithosphere (the colder, denser part of the mantle that, together with the crust, comprises the oceanic plates) thickens, and ...
It runs along an oceanic-continental boundary, where the oceanic Nazca plate subducts beneath the continental South American plate. Oceanic trenches are 50 to 100 kilometers (30 to 60 mi) wide and have an asymmetric V-shape, with the steeper slope (8 to 20 degrees) on the inner (overriding) side of the trench and the gentler slope (around 5 ...
This causes the oceanic plate to buckle and usually results in a new mid-ocean ridge forming and turning the obduction into subduction. [citation needed] Orogenic belts occur where two continental plates collide and push upwards to form large mountain ranges. These are also known as collision boundaries. Subduction zones occur where an oceanic ...
The boundary between Asia and Europe is unusual among continental boundaries because of its largely mountain-and-river-based characteristics north and east of the Black Sea. Asia and Europe are considered separate continents for historical reasons; the division between the two goes back to the early Greek geographers .