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Earth: Atlantic Ocean: ≈10,000 km (6,000 mi) ≈6,000 km (4,000 mi) 7.758 km (4.821 mi) Length taken to be that of the Mid-Atlantic Ridge. (The ridge also has a secondary rift valley running its length.) The width is an average taken along the spreading ridges (Georgia–Senegal, Brazil – Bight of Benin, etc.).
The axis of the rift area may contain volcanic rocks, and active volcanism is a part of many, but not all, active rift systems. Major rifts occur along the central axis of most mid-ocean ridges, where new oceanic crust and lithosphere is created along a divergent boundary between two tectonic plates.
Plate tectonics was a suitable explanation for seafloor spreading, and the acceptance of plate tectonics by the majority of geologists resulted in a major paradigm shift in geological thinking. It is estimated that along Earth's mid-ocean ridges every year 2.7 km 2 (1.0 sq mi) of new seafloor is formed by this process. [50]
Continental-continental divergent/constructive boundary Oceanic divergent boundary: mid-ocean ridge (cross-section/cut-away view). In plate tectonics, a divergent boundary or divergent plate boundary (also known as a constructive boundary or an extensional boundary) is a linear feature that exists between two tectonic plates that are moving away from each other.
At this point basaltic oceanic crust and upper mantle lithosphere begins to form between the separating continental fragments. When one of the rifts opens into the existing ocean, the rift system is flooded with seawater and becomes a new sea. The Red Sea is an example of a new arm of the sea.
The infill of magmas in the form of dykes helps to define the shape of a volcano. A higher frequency of intrusive events along rift zones leads to elongated topographies of the affected edifices. [6] Mathematical models show how the presence of rift zones contributes to a central horizontal bulge or ridge parallel to the orientation of the ...
The Red Sea Rift is a mid-ocean ridge between two tectonic plates, the African plate and the Arabian plate. It extends from the Dead Sea Transform fault system, and ends at an intersection with the Aden Ridge and the East African Rift , forming the Afar triple junction in the Afar Depression of the Horn of Africa .
The Pacific Ocean evolved in the Mesozoic from the Panthalassic Ocean, which had formed when Rodinia rifted apart around 750 Ma. The first ocean floor which is part of the current Pacific plate began 160 Ma to the west of the central Pacific and subsequently developed into the largest oceanic plate on Earth. [1]