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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 ...
In geology, a rift is a linear zone where the lithosphere is being pulled apart [1] [2] and is an example of extensional tectonics. [3] 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 ]
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.
The Rio Grande rift is a north-trending continental rift zone. It separates the Colorado Plateau in the west from the interior of the North American craton on the east. [ 1 ] The rift extends from central Colorado in the north to the state of Chihuahua , Mexico , in the south. [ 2 ]
In geology, anorogenic magmatism is the formation, intrusion or eruption of magmas not directly connected with orogeny (mountain building). [1] Anorogenic magmatism occurs, for example, at mid-ocean ridges, hotspots and continental rifts.
The Atlantic continental margin off Portugal and Spain is unique. [citation needed] In the zone between continental crust and oceanic crust there is a 100 km wide zone of exhumed continental mantle. During the rift splitting Newfoundland from Iberia there was very little vulcanism and the rift was starved of magma.
Where hotspots are developed beneath the continents the products are different, as the mantle-derived magmas cause melting of the continental crust, forming granitic magmas that reach the surface as rhyolites. The Yellowstone hotspot is an example of continental hotspot magmatism, which also displays time-progressive shifts in magmatic activity.
The West and Central African Rift System, with the Central African Shear Zone labeled CASZ. The West and Central African Rift System (WCARS) is a rift system composed of two coeval Cretaceous rift sub-systems, the West African Rift sub-system (WAS) and the Central African Rift sub-system (CAS). [1]