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The most extensive rift valley is located along the crest of the mid-ocean ridge system and is the result of sea floor spreading.Examples of this type of rift include the Mid-Atlantic Ridge and the East Pacific Rise.
A team led by Marie Tharp and Bruce Heezen concluded that there was an enormous mountain chain with a rift valley at its crest, running up the middle of the Atlantic Ocean. Scientists named it the 'Mid-Atlantic Ridge'. Other research showed that the ridge crest was seismically active [45] and fresh lavas were found in the rift valley. [46]
The Great Rift Valley (Swahili: Bonde la ufa) is a series of contiguous geographic depressions, approximately 6,000 or 7,000 kilometres (4,300 mi) in total length, the definition varying between sources, that runs from the southern Turkish Hatay Province in Asia, through the Red Sea, to Mozambique in Southeast Africa.
(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 greatest depth is the Romanche Trench. (The Puerto Rico Trench is not part of the rift system.) Great Rift Valley: 6,000 km (3,700 mi) 220 km (140 mi) 2 km (1 mi)
Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben with normal faulting and rift-flank uplifts mainly on one side. [4] Where rifts remain above sea level they form a rift valley, which may be filled by water forming a rift lake.
The Midcontinent Rift System (MRS) or Keweenawan Rift is a 2,000 km (1,200 mi) long geological rift in the center of the North American continent and south-central part of the North American plate. It formed when the continent's core, the North American craton , began to split apart during the Mesoproterozoic era of the Precambrian , about 1.1 ...
About 180 million years ago, a mantle plume under southern Gondwana caused bulging of the continental crust in the area that would later become southern Africa. [2] Within 10–20 million years, rift valleys formed on either side of the central bulge and flooded to become the proto-Atlantic Ocean and proto-Indian Ocean more or less along the present southern African coastline and separating ...
If this occurs on land a rift is formed, which eventually becomes a rift valley. The most active divergent boundaries lie under the sea. The most active divergent boundaries lie under the sea. In the ocean, if magma or molten rock ascent from the mantle and fill the gap created by two diverging plates, a mid-ocean ridge is formed.