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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. Failed rifts are the result of continental rifting that failed to continue to the point of break-up.
Volcanic strata protrude at Isle Royale and the Keweenaw Peninsula [9]. Lake Superior occupies a basin created by the rift. [3] Near the present lake, rocks produced by the rift can be seen on the surface of Isle Royale and the Keweenaw Peninsula of the Upper Peninsula of Michigan, [9] northwest Wisconsin, [10] and on the North Shore of Superior in Minnesota and Ontario. [4]
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.
Rift valleys are also known to occur on other terrestrial planets and natural satellites. The 4,000 km long Valles Marineris on Mars is believed by planetary geologists to be a large rift system. [ 7 ] [ 8 ] Some features of Venus, most notably, the 4,000 km Devana Chasma [ 9 ] and a part of the western Eistla, and possibly also Alta and Bell ...
The Wilson cycle theory is based upon the idea of an ongoing cycle of ocean closure, continental collision, and a formation of new ocean on the former suture zone.The Wilson Cycle can be described in six phases of tectonic plate motion: the separation of a continent (continental rift), formation of a young ocean at the seafloor, formation of ocean basins during continental drift, initiation of ...
A map of the Afar triangle in East Africa, an example of an RRR junction and the only triple junction on Earth that can be seen above sea level. An RRR junction is always stable using these definitions and therefore very common on Earth, though in a geological sense ridge spreading is usually discontinued in one direction leaving a failed rift ...
Obduction zones occurs when the continental plate is pushed under the oceanic plate, but this is unusual as the relative densities of the tectonic plates favours subduction of the oceanic plate. 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]
A map of East Africa showing some of the historically active volcanoes (as red triangles) and the Afar Triangle (shaded at the center), which is a so-called triple junction (or triple point) where three plates are pulling away from one another: the Arabian plate and two parts of the African plate—the Nubian and Somali—splitting along the East African Rift Zone Main rift faults, plates ...